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The staff of has shown that the sum of all the integers from $0$ to $\infty$ is $-\frac1{12}$. Recently I was looking for the sum of all the (positive) integers from $0$ to $n$ and I found that: $$\sum_{i=0}^n i=\frac{n(n+1)}{2}$$ So I decided to take the limit: $$\lim_{n\to \infty}\frac{n(n+1)}{2}$$ but that tends towards $\infty$ when I expected that to be $-\frac1{12}$! Where did I got wrong? (the result is also confirmed by Wolfram Alpha) | $\displaystyle\sum_{n=1}^\infty \frac{1}{n^s}$ only converges to $\zeta(s)$ if $\text{Re}(s) > 1$. Why should analytically continuing to $\zeta(-1)$ give the right answer? |
This is my first day on Ubuntu. My computer comes with preloaded Ubuntu. When connected to my external Hard Drive, I got this message. My understanding is that it says Ubuntu is not able to mount my hard drive and gives the following error. Please help me understand this thing. | I am having trouble mounting my external hard drive, every time I try and do so I get the following message: "Error mounting /dev/sdb1 at /media/fuzzy27/My Book: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sdb1" "/media/fuzzy27/My Book"' exited with non-zero exit status 13: $MFTMirr does not match $MFT (record 0). Failed to mount '/dev/sdb1': Input/output error NTFS is either inconsistent, or there is a hardware fault, or it's a SoftRAID/FakeRAID hardware. In the first case run chkdsk /f on Windows then reboot into Windows twice. The usage of the /f parameter is very important! If the device is a SoftRAID/FakeRAID then first activate it and mount a different device under the /dev/mapper/ directory, (e.g. /dev/mapper/nvidia_eahaabcc1). Please see the 'dmraid' documentation for more details." How do I go about or what do I need to do in order to fix this error/problem without losing any of the data on my hard drive? Is there no other way of fixing it without having to reinstall windows or finding someone using windows? |
Time ago I saw a profile with an image like this one: So I copied the image url but adapting it to my own user id and I put it in my page. It has been a while and my reputation is still the same in the image, so I've realized that the url now is http://i.stack.imgur.com/2QkYT.png (I remember before was something like http://www.stackexchange.com/users/[my_user_id].png) I've been looking in the help section,another profiles, but no clue. Is still working this functionality? if so, what's the url to generate it? Is specified in some help site? FAQ? | I want to put a link to my SO profile on my homepage. I remember a codesnippet i saw somewhere that would basically display my Username and my reputation. Where was that? |
I have an exercise which involves groups. It's probably common, but I don't know how to solve it. It sounds like this: Let (G, $\cdot$) be a group and x, y $\in$ G. Show that ord(xy) = ord(yx). where ord(x) is the order of x. I just tried to write $xy\cdot xy \cdot \space ...\space\cdot xy = x \cdot (yx) \cdot (yx) \cdot\space ...\space \cdot (yx) \cdot y$, letting x and y outwards. I don't know if this is a good step and I don't know how to continue. I would be glad if someone could help me. | How do I prove that if $a$, $b$ are elements of group, then $o(ab) = o(ba)$? For some reason I end up doing the proof for abelian(ness?), i.e., I assume that the order of $ab$ is $2$ and do the steps that lead me to conclude that $ab=ba$, so the orders must be the same. Is that the right way to do it? |
In C#, I've seen that some people use lower case string and sometimes String with Uppercase S. Is there any difference in using them? string type = "Small"; String type = "Large"; | Example (note the case): string s = "Hello world!"; String s = "Hello world!"; What are the guidelines for the use of each? And what are the differences? |
I’m running out of space to put things, so I just pile them into my ---------- closet. 1) over-crowded little dark bedroom 2) little over-crowded dark bedroom I think #1 is far better than #2. However, let me know whether #2 is a possibility or not. | I remember being taught that the correct order of adjectives in English was something along the lines of "Opinion-Size-Age-Color-Material-Purpose." However, it's been a long time and I'm pretty sure I've forgotten a few categories (I think there were eight or nine). Can anyone fill them in? |
So I wonder if Pikachu is female or male, because in the Movie Pokémon - I choose you!, Pikachu was voiced by a woman. If he was male, I don't think they would voice that Part by a woman. Also, Ash’s Pikachu has no heart shape at the end of it’s tail, but that proves nothing, because that wasn’t a Thing when Pomémon was created. | I was recently having a discussion about Pokémon, and it came up that none of us were sure whether Ash's Pikachu in the series was male or female. Some (myself included) always thought it was male, whereas others could've sworn it was female. Was there ever any canon evidence to point in one direction or another? |
So, since I've attended to the introduction to number theory course I couldn't stop thinking about this problem: Prove that $\sqrt{2}$ is irrational using the Well Ordering Principle. Ok, I started defining a set $X = \{ x = z \sqrt{2}; z \in \mathbb{Z} \}$ and supposing that there exists an $a \in \mathbb{Z}$ such that $a < x$, $\forall x \in X$. Hence, there exists an $x' \in X$ such that $ x' \leq x$, $\forall x \in X$. And that's when I can't proceed further. Is there a problem in the way I've defined the set or it is just a "leap" that I'm not seeing? Thanks in advance. | I am having a problem understanding this proof. Suppose that $\sqrt{2}$ was rational. Then there would exist positive integers $a,b$ such that $\sqrt{2}=\frac{a}{b}$. Consequently, the set $S=\{k\sqrt{2} : k \text{ and } k\sqrt{2}$ are positive integers $\}$ is nonempty set of positive integers. Therefore, by the well-ordering property, $S$ has a smallest element, say, $s = t \sqrt{2}$. We have $s \sqrt{2}-s = s\sqrt{2}-t\sqrt{2}=(s-t)\sqrt{2}$. Because $s\sqrt{2} = 2t$ and $s$ are both integers, $s\sqrt{2} - s = s\sqrt{2}-t\sqrt{2} = (s-t)\sqrt{2}$ must also be an integer. Furthermore, it is positive, because $s\sqrt{2}-s = s(\sqrt{2}-1)$ and $\sqrt{2} > 1$. It is less than $s$, because $\sqrt{2} < 2$ so that $\sqrt{2}-1 < 1$. This contradicts the choice of $s$ as the smallest positive integer in $S$. It follows that $\sqrt{2}$ is irrational. My main problem here is how they got the set $S$. My second confusion is the algebra part $s \sqrt{2}-s$. How did they come up with this? If someone can explain this proof to me it would be great! thank you |
I am having trouble trying to merge two shapefiles in R. One of them has 5 polygons and the other one has 1, so I would like to obtain a final shapefile with 6 polygons. I try to replicate the merge function from ArcGIS, unsuccessfully though. I have tried with several functions (gUnion, unión from raster package, merge), but all of them create more columns instead of adding a new row. Could anybody help me to solve this issue? I have tried with the methods proposed in but they do not work in my case. | I have created 2 polygons in QGIS. Using them in R, polygons become automatically SpatialPolygonsDataFrame (SPDF). I would like to merge them into single SPDF (as is super easy in ArcGis using Tool Merge). I am sure that there should be simple way how to complete that in R, but I can't find how. the merge function seems to merge only data.frames, aggregate function dissolve multiple polygons into one shp, gIntersect (by typing join function) returns logical value, not at all the SPDF. data are available here: library(sp) library(raster) library(rgeos) library(spatstat) library(rgdal) library(maptools) setwd("C:/...") a<-readOGR(dsn=getwd(), layer="pol.a") b<- readOGR(dsn=getwd(), layer="pol.b") ab<-merge(a, b) # what tool if not "merge" to use?? |
Consider a sequence of discs $U_1, U_2,\dots,U_n \subset \mathbb R^2$. Let $S_{ij}$ denote the area of the intersection of $U_i$ and $U_j$. Prove that $$\begin{vmatrix} S_{11} & S_{12} & … & S_{1n} \\ S_{21} & S_{22} & ... & S_{2n} \\ … & … & \ddots & … \\ S_{n1} & S_{n2} & … & S_{nn} \end{vmatrix} \ge 0$$ For $n = 2$, we have $$\begin{vmatrix} S_{11} & S_{12} \\ S_{21} & S_{22} \end{vmatrix} = S_{11}S_{22} - S_{12}S_{21} \ge 0$$ since the diagonal elements are the largest. So the claim holds. I was planning to go through induction but it seems like to get a big deal to see how the determinant will change after adding a new disc to the collection. What we also have are the matrix is symmetric so that $S_{ij} = S_{ji}$ and therefore the eigenvalues are real (I don't see any use of this though). | Consider disks $s_1, \cdots, s_n$ in the plane and let $a_{ij}$ be the area of $s_i\cap s_j$. Is it true that for any real numbers $x_1,\cdots, x_n$ we have $$ \sum_{i,j=1}^n x_ix_j a_{ij} \geq 0$$ Equivalent formulation: one can put $a_{ij}$ into a matrix $A$ and ask whether it is positive semidefinite. For $n=2$ this is true since $$a_{12}^2\le \min(a_{11},a_{22})^2 \le a_{11}a_{22} $$ |
I've noticed that the message above appears sometimes when I choose "Improve" in the suggested edit review queue, as . Given that the Community approval and my edit have the same time stamp, I believe this is an automated process. , the suggest edit had 3 approve votes (by real users) prior to my edit, so the Community notice did not appear. Could someone please clarify what is going on? | Take a look at . There were two "Approve" marks, but then rejected it, and that was it. The suggestion was rejected with a 1-2 reject-approve ratio. From Community's , it states that "[it is] not really a person," and is actually "a background process" that does the following: Randomly poke old unanswered questions every hour so they get some attention Own community questions and answers so nobody gets unnecessary reputation from them Own downvotes on spam/evil posts that get permanently deleted Own suggested edits from anonymous users None of those mention that it works the review queue. In addition, the right side of the states that "Stack Overflow is moderated by []" - NOT an automated bot. If the automated bot can do review on its own, why would we be reviewing manually? So, all together, I have a few small questions: Is the ability to make an decision on behalf of everyone moderator-only or Community-only? Why is a computer allowed to make decisions for us? Why does Community's not mention that it can do that? Is Community really only software, or is there some interaction behind the scenes? |
I would like to know how to enable the lightning app builder in my developer edition. Thanks in advance. Best regards | I was googling unsuccessfully. I've created Aura components without any problem, but I can't figure out how enabled this: I'm trying to enable that feature in a Dev Winter 15. |
I have changed the size of the vhd. I am running GParted from an iso through Oracle VirtualBox Manager. Gparted will not let me add the extra memory unallocated to the main partition. Can anyone please help? Print Screen of GParted: Note- size is 40Gb, allocated memory is 15GB and unallocated memory is 23GB. | Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers. Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions). Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space. How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions? |
A fair coin is flipped repeatedly until it turns up tails five times. What is the expected number of heads before that happens? Based on the link given in the comment, I have found it can be solved using the recursion $E(n)=\frac{1}{2}(E(n)+1)+\frac{1}{2}(E(n-1))$ which is equivalent to $E(n)=E(n-1)+1$. Is it correct? | A fair coin is tossed repeatedly until 5 consecutive heads occurs. What is the expected number of coin tosses? |
In QGIS is there a way to filter a layer using the Query Builder to show all values which include a particular phrase. For example I have a list of organisations and I want to filter all those which include the word Wales. I can do this using the attribute table but not in the map view so that the map just shows these selected features. | I am trying to display certain features in a shapefile-based layer using QGIS. I have found the subset function in the properties panel, which does exactly what i want, but is too tedious given that I have to manually sift through a large number of features. Is there a quicker way to do this? I am using both shapefiles and postGIS best, dietmar |
I've made a logo in photoshop, it's high quality. When I then export and try to upload as my instagram profile picture, it becomes blurry. Is anyone able to help. | After uploading an image, Facebook converts it to a new image. Their conversion process introduces artifacts and mottling to the magenta-ish parts of the image. Original image: Facebook's conversion: Are there ways to preserve the original quality of this image and have the image appearance on Facebook reflect more of the original quality? |
I am struggling with possibly easy to solve question. I have a unordered list and 3 items inside a responsive divs. I have managed to centre it horizontally but the vertical is where I am struggling with. <div class="left"> <div class="boxtext"> <div class="insidetext"> <ul> <li>WATER</li> <li>JUICE</li> <li>TEA</li> </ul> </div> </div> </div> .left { @include aspect-ratio(16,9); width: 50%; height: 100vh; min-width: 300px; position: relative; background-size: cover; background-color:#333; position: relative; } @media (max-width:768px) { .left { width: 100%; height: 70vh; } } .boxtext { @include aspect-ratio(16,9); border: solid white 0.15em; height: 70vh; width: 70%; margin: auto; position: absolute; top: 0; left: 0; bottom: 0; right: 0; text-align: center; } @media (max-width:768px) { .boxtext { width: 70%; height: 70%; } } .insidetext { @include aspect-ratio(16,9); background-color: aliceblue; height: 70%; width: 70%; margin: auto; position: absolute; top: 0; left: 0; bottom: 0; right: 0; font-size: 9vh; text-align: center; min-height:100px; } .insidetext li { list-style-type:none; } .insidetext ul { display: table; margin: 0 auto; } .insidetext ul,li { list-style-type: none; list-style-position:inside; margin:0 auto; padding:0; vertical-align:middle; } here is a test: | I have a div with two images and an h1. All of them need to be vertically aligned within the div, next to each other. One of the images needs to be absolute positioned within the div. What is the CSS needed for this to work on all common browsers? <div id="header"> <img src=".." ></img> <h1>testing...</h1> <img src="..."></img> </div> |
The questions is: Evaluate $$\lim_{x\to 0} \frac{a^x -1}{x}$$ without applying L'Hopital's Rule. Does this question fundamentally same as asking if the $\lim_{x\to 0} \frac{a^x -1}{x}$ exists? rather than straightway asking to find the limit. That means are questions (1) proving if the limit of a function exists and (2) asking what is the limit of that function, essentially same question? | Taking as our definition of exponentiation repeated multiplication (extended to real exponents by continuity), can we show that the limit $$\lim_{h\to 0}\dfrac{a^h-1}{h}$$ exists, without l'Hôpital, $e$, or even natural logarithm? Sure, l'Hôpital will work, but that's circular if we're developing calculus of transcendentals from first principles. There is to this question already by user Neal, but he uses the exponential function with base $e$ (it's been answered many times: see also , , and ). But using the special properties of $e$ strikes me as circular too; not literally logically circular, in the sense that we are invoking results we're trying to prove, since there are definitions of $e^x$ which make it trivial to verify the derivative. But perhaps pedagogically circular for a complete novice, the special properties of $e$ appear unmotivated because they cannot be justified without reference to the very derivative we are trying to compute (or else a detour through logarithms, but let's not). Can we find nice squeeze theorem bounds like Neal has, but for the function $a^x$ instead of $e^x$, with the additional handicap that we can't just write $a^x=e^{x\log a}$? I thought to substitute a series expansion for $\log a$, but didn't come up with any bounds that were nicely polynomial in both $x$ and $a$. I wonder whether the geometric proof of $\lim (\sin x)/x$ (see for example, robjohn's answer ) could be adapted. Obviously without a reference to natural logarithm, we cannot compute the value of the limit. But I just want to show it exists (via squeeze theorem or monotone convergence). Once we know this limit exists, we can show it behaves like a logarithm, whence there is a unique base for which the limit is 1, which we call $e$. The rest of the development of calculus of exponentials and logs follows easily. This seems like the approach that would appear the most accessible yet motivated to a novice calculus student. An analogous limit to $\lim\dfrac{a^h-1}{h}$ for understanding to differentiating exponential functions, are the limits $\lim\limits_{n\to\infty} (1+\frac{1}{n})^n$ and $\lim\limits_{n\to\infty} (1+\frac{1}{n})^{n+1}$ for differentiating the logarithm, if you prefer to start with that as your primitive concept. Both limits are shown to exist using (see WimC's answer for the first limit, and see David Mitra's answer for the second limit). I tried without success to use Bernoulli's inequality to show my sequence was monotone. This limit can also be analyzed using as seen in user94270's answer to . So that inequality may help here. I would also accept an explanation of why the limit cannot be computed without transcendental techniques, or an opinion why this is not a pedagogically sound approach to introducing the calculus of exponentials and logarithms. Edit: has a nice solution by Paramanand Singh to a closely related problem. |
In Lawrence Krauss's excellent book "Universe from Nothing" and his related lectures, he cites findings of the BOOMERANG-instrument observations in Anarctica as used to measure the diameter of slightly warmer regions in the cosmic microwave radiation background. Dr. Krauss explains that we are able to measure this because these structures formed in the last scattering surface when the universe was only ~300K years old. Dr. Krauss presents the argument that since gravity cannot travel faster than the speed of light, objects farther apart would not have had time to interact gravitationally. Therefore, these clumps can be no more than ~300K light-years across. How do we know that a perturbation in a gravitational field cannot travel faster than the speed of light? I know that special relativity applies to electromagnetic energy, i.e. "light", but how do we know it applies to gravity as well. After all, gravity is related by general relativity to the curvature of space-time itself? Are perturbations in the curvature of space-time (gravitational waves) necessarily constrained by special relativity? | A thought experiment: Imagine the Sun is suddenly removed. We wouldn't notice a difference for 8 minutes, because that's how long light takes to get from the Sun's surface to Earth. However, what about the Sun's gravitational effect? If gravity propagates at the speed of light, for 8 minutes the Earth will continue to follow an orbit around nothing. If however, gravity is due to a distortion of spacetime, this distortion will cease to exist as soon as the mass is removed, thus the Earth will leave through the orbit tangent, so we could observe the Sun's disappearance more quickly. What is the state of the research around such a thought experiment? Can this be inferred from observation? |
My pc has been experience lag ever since it came back from a fan upgrade. Now i noticed that my cpu usage spikes from 10% to 80% and back in seconds, i see that svchost.exe is consuming 25% and system is spiking from 0% to 25% (i have 4 cores so it basicly consumes one core each). Does anybody has any idea of what to do? Thanks in advance. EDIT: I installed update KB3102810 and it partialy solved the problem,svchost does not spike anymore but System still spikes, meanwhile i noticed that in the services MsMpSvc, spikes up to 17%. | I installed Windows 7 fresh and installed SP1. Now, when I try to check manually for Windows Updates it just hangs on the Checking for updates screen. I tried running the tools in , but this did not fix the issue either: No matter what I do it just hangs on the "Checking for updates..." screen and goes no further. |
So I noticed recently that when I try to watch YouTube videos or Netflix in full screen on my Macbook Air, the whole screen will wash out with orange and yellow and I can't see anything, but it's perfectly fine if I don't watch it in fullscreen. And on Netflix if I use subtitles, it's normal when someone is talking, but when the text disappears the screen gets an orange tint again. I've tried calibrating the colors through the display section of system preferences but it always tells me that there is an error. I've searched for someone who is having a similar problem but haven't found anyone. Please help! Thank you. | I noticed recently that when I try to watch YouTube videos or Netflix in full screen on my Macbook Air, the whole screen will wash out with orange and yellow and I can't see anything. But it's perfectly fine if I don't watch it in fullscreen. And on Netflix, if I use subtitles, it's normal when someone is talking, but when the text disappears the screen gets an orange tint again. I've tried calibrating the colors through the display section of system preferences but it always tells me that there is an error. I've searched for someone who is having a similar problem but haven't found anyone. |
I have two different functions in javascript. Function A) is a function, which shows a countdown on the page. Function B) , the other function is completely indepentent from function A). But, when I start an alert() or confirm() in function B), the countdown in function A) pauses. So every background script is pausing. Is there a way to disable the pause without changing the alert() or confirm() to jquery? This script is only running on one specific machine, so I also could change some parameters in the browser. thanks in advance | I'm looking for something like alert(), but that doesn't "pause" the script. I want to display an alert and allow the next command, a form submit(), to continue. So the page will be changing after the alert is displayed, but it won't wait till the user has clicked OK. Is there something like this or is it just one of those impossible things? |
I posted a question on SO, intending to use the tag "batch". After completing the post, the tag mysteriously changed to "batch-file". I tried editing it several times to switch it to "batch" but each time it reverted to "batch-file" after saving. This is the post: | What are tag synonyms? How can tag synonyms be distinguished from "real" tags? How are new tag synonyms created? Who can create tag synonyms? How can I delete/reverse/undo bad tag synonyms? What are merged tags? |
Look at this snippet: void Sample_Compositor::createEffects(void) { Ogre::CompositorPtr comp3 = Ogre::CompositorManager::getSingleton().create("Motion Blur", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME); { { Ogre::CompositionTargetPass *tp = t->getOutputTargetPass(); tp->setInputMode(Ogre::CompositionTargetPass::IM_NONE); { Ogre::CompositionPass *pass = tp->createPass(); pass->setType(Ogre::CompositionPass::PT_RENDERQUAD); pass->setMaterialName("Ogre/Compositor/MotionBlur"); pass->setInput(0, "sum"); } } } } If this code is legit, how do these blocks work? | What is the purpose of anonymous { } blocks in C style languages (C, C++, C#) Example - void function() { { int i = 0; i = i + 1; } { int k = 0; k = k + 1; } } Edit - Thanks for all of the excellent answers! |
I know Euler's formula and how to take complex exponents, but in it it's $e$ to an imaginary angle, not a number, it seems. From my understanding pi itself is not an angle, but $\pi$ radians is. And since cosine can only take in an angle, or at least a representation of one, and the variable is the same everywhere in Euler's formula, the exponent should be an angle and not a number. The question is then raised could I then say $e^{180i}=-1$? Surely this has a single numerical value though, right? I've been bothered by this for a long time. Am I wrong or how can I take an exponent with a complex number? Edit for the duplicate: I understand how to take them and how they're supposed work and be justifyed/proved, but raising something to the power of an angle which is what I thought was meant to be happening made me question how they actually worked that could allow this. | How does one find the algebraic solution of a Complex number raised to the power of another Complex number? Here is the work I have done so far, if there are any mistakes please inform me. A real number with a Complex Exponent: $$A \in \Bbb R, \space z \in \Bbb C,\space z = x + iy$$ $$A^z = A^{x+iy} = A^xA^{iy}$$ $$\implies e^{iy\ln A} = A^{iy}$$ $$\exp(iy\ln A) = \cos (y\ln A)+i\sin(y\ln A)$$ $$A^z = A^x[\cos (y\ln A)+i\sin(y\ln A)]$$ A Complex number with a Complex Exponent: [Using previous variables] $$C \in \Bbb C,\space C = a +bi\space|\space re^{i\theta}, \theta =\arg C$$ $$C^z = (a+ib)^z$$ [After previous mistake the following notes are inaccurate] $$C^z = a^x[\cos (y\ln a)+i\sin(y\ln a)] + ib^xib^{iy}$$ And this is as far as I could go as the expansion of $ib^xib^{iy}$ is being problematic. Could I have some help with this expansion? |
I was just wondering this because of noticing a lot of people I've worked with typed this way. Examples: Okay, that's great . Thanks, Stephanie . Was there anything else ? I was wondering if there is something that this could derive from. | In written English (mainly online) I often come across sentences ending with a question or an exclamation mark with a space before it. Is it always just an error or a typo? Or there are cases when it is a correct English, for example after closing parentheses or some other punctuation marks? |
I wanted to buy a few parts so after searching I came upon this website. I want to know if this website is fake so which website is appropriate for asking this question? | Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com. |
I have a 298 GB HDD and it shows that I have 179 GB free. When I try to shrink my C drive, it will only allow me to shrink 9474 Mb. How do I increase this number? I have already defrag the drive. | I have just bought an HP laptop with Windows 7 (64 bit). It has a 500 GB HDD with three partitions: a small hidden system partition, a 12 GiB HP recovery partition, and a 450 GiB C: boot partition. I would like to split this large C: partition into two partitions, leaving only 100 GiB for the system, and giving the rest to a new data partition. Although the Windows built-in Disk Management utility has an option to shrink the bootable partition, it only allows me to shrink it roughly by half, even though only 20 GiB on the partition is used. As far as I understand, system unmovable files lie in the middle of the partition, preventing Disk Management utility to do what I want. And since new HP laptops don't come with OS installation disks (they only allow you to create recovery disks yourself), I can't just repartition HDD and then reinstall OS. So, is there a way to shrink the C: bootable partition and preserve Windows 7 working? P.S.: I have tried to use the third-party utility, and after shrinking the partition, Windows 7 stopped booting, with a . System recovery didn't work, and I had to do factory recover. Since this is a long process, I would like to avoid doing it again :) So, please, suggest only proven solutions. |
My attempt : Suppose $H$ is another subgroup of $S_5$ of order $60$ by Lagrange's Theorem $\vert H\cap A_5\vert ||H|$, then $|H \cap A_5| \in\{1,2,3,5,6,10,20,30,60\}$ $$\Rightarrow |HA_5| =\frac{|H||A_5|}{|H \cap A_5|}=3600,1800,1200,900,720,600,360,180,120,60$$ So, the only candidates for the order of $|H \cap A_5|$ are $30$ and $60$. Then I want to claim that the order must be $60$. thus $|H \cap A_5|=|A_5|$ $$\Rightarrow H=A_5$$ But I didn't know how to show the former case doesn't hold. Please give me a hint please! PS. I haven't learned the concepts of normal group and simple group. So, I would like you to explain without using these concepts! Thank you. | How to prove that the only subgroup of the symmetric group $S_n$ of order $n!/2$ is $A_n$? Why isn't there other possibility? Thanks :) |
I am trying to train a Deep Q Network () for a simple control task. The agent starts in the middle of a 1-dimensional line, at state 0.5. On each step, the agent can move left, move right, or stay put. The agent then receives a reward proportional to the absolute distance from its starting state. If the agent reaches state 0.35 or state 0.65, then the episode ends. So, effectively the agent is encouraged to move all the way to the left, or all the way to the right. For now, I am just trying to train a deep neural network in Keras / Tensorflow, to predict the q-values of the three actions, in any given state. At each time step, actions are chosen randomly, so I am just trying to see if the network can predict the correct q-values, I am not trying to get the agent to actually solve the task. However, my network is struggling to learn the correct function. In this first figure below, the dots represent the training data available to the network on each weight update. These are stored in the experience replay buffer in the standard q-learning algorithm. As can be seen, states further from the centre have higher q-values, as would be expected. Also, when the state is greater than 0.5, higher q-values are assigned to the "move right" action, as would be expected, and vice versa. So, it seems that the training data is valid. In the next figure below, the predicted q-values are shown from my network. To get these values, I sampled uniformly from the range 0.35-0.65 to get the inputs, and then plotted the q-values for each action (the three coloured lines). The gradient is computed with respect to the difference between these predictions, and the training data in the first figure. So, these lines should match up to the points in the first figure. However, clearly they do not. They are predicting roughly the right values, but the shape of the lines are not consistent with the training data. In the third figure below, I now plot the training loss for this network. So, it appears that training has converged, even though there is still significant error between the training data and the predictions. I am using mean squared error loss. Finally, here are some details on my network itself. I use 1 layer of 16 hidden nodes, each with Relu activations, and the final layer has 3 nodes, one for each action. Although this is a simple network, it has enough capacity to learn the simple function in the first figure, from my prior experiments. I use the AdamOptimizer for optimisation, with a learning rate of 0.01, and I have also tried with a learning rate of 0.001 which also does not give the desired results. My batch size is 32. As with the standard Deep Q Network approach, I used a separate network for training the q values to the network used to predict the q values for the other states (as used in the Bellman equation). So, I am puzzled as to what is going on. My network should be able to fit the training data, but it is not able to. I am not sure whether this is a problem with my optimisation, my network architecture, or my q learning algorithm. My intuition is that the learning rate is too low, because the predicted q values show a shape significantly different to the training q values, and so the network needs to be bumped significantly in the right direction. However, I am already using a learning rate of 0.01, which is very high. Another thought I had is that the training error is pretty small (3 x 10^-4), and so it may not be possible to reduce this any more. Therefore, I would need to increase the size of the predicted q values (e.g. by increasing the scale of the reward), such that the absolute error is much larger, and therefore the optimiser can compute effective gradients. Does this make sense? Any suggestions? | I'm training a neural network but the training loss doesn't decrease. How can I fix this? I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set. This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion: If your neural network does not generalize well, see: |
I have an editor which has .exe format and i want to install it on Ubuntu 16.04. How it is possible to install this application in Ubuntu? | Can .exe and .msi files (Windows software) be installed in Ubuntu? |
I am trying to match the contents between BEGIN and END into a capture group called numbers from this string note: string note = @"BEGIN 781-222-3311 9789001122 7817770000 to 7817770010 END"; The variable I am putting the matched group value into is numbers. What I am using to match the string is the following: string numbers = ""; Regex numberEncapsulationRegex = new Regex(@"begin\n(?<numbers>.+)\nend", RegexOptions.IgnoreCase); Match numberCatch = numberEncapsulationRegex.Match(note); if (numberCatch.Success) { Console.WriteLine("SUCCESS: \n"); numbers += numberCatch.Groups["numbers"].Value; } I have tried using RegexOptions.Multiline along with RegexOptions.IgnoreCase, and have also tried using: (?i:begin)\n(?<numbers\>.+)\n(?i:end) (?i:begin)(\n?<numbers>.+\n)(?i:end) (?<=BEGIN)(.*)(?=END) Cannot get this to work. Thank you for reading and for helping, if willing. | For example, this regex (.*)<FooBar> will match: abcde<FooBar> But how do I get it to match across multiple lines? abcde fghij<FooBar> |
I have a ceiling light that is controlled by two switches, however when one of the switches is off the other switch does not work. What is the issue and how can I fix it? | I have a 3 way switch that was wired incorrectly when the switches were replaced with a different color switch. Is there a methodical way for me to identify which wires represent which piece of the system so I can correct the bad wiring? Currently if switch 1 is on, switch 2 can turn light on or off. If switch 1 is off, then switch 2 does nothing. |
I would like to know if I would need a 1.5m x 2m Backdrop, what's the size of canvas I've to create on photoshop?Thanks! | (This question is meant to be a resource to direct others to given that this is a common question.) Given the task of creating an image that will be printed at a certain size, what pixel dimensions and resolution should I be setting my file at? |
A field worker has to make altogether 43 visits, at least one on each day. Is there a period of consecutive days on which he makes exactly 21 visits if he makes his visits on 22 days? What happens to the problem if he makes his visits on 23 days instead of 22 days? How can I approach to solve this problem using Pigeonhole principle, thanks. | This is for self-study. This question is from Rosen's "Discrete Mathematics And Its Applications", 6th edition. An arm wrestler is the champion for a period of 75 hours. (Here, by an hour, we mean a period starting from an exact hour, such as 1 P.M., until the next hour.) The arm wrestler had at least one match an hour, but no more than 125 total matches. 1 - Show that there is a period of consecutive hours during which the arm wrestler had exactly 24 matches. 2 - Is the statement in the previous exercise true if 24 is replaced by a) 2? b) 23? c) 25? d) 30? My solution to part 1 is the following, based on Rosen's solution to a similar problem given as example in the text: 1 - If I consider $a_i$ to be the number of competitions until the $i^{th}$ hour, then, $1\leq a_1<a_2<\cdots<a_{75}\leq 125$, because there are no more than 75 hours and the total number of competitions is no more than 125. Now I will add 24 to all the terms of the above inequality: $25\leq a_1+24<a_2+24<\cdots<a_{75}+24\leq 149$. There are 150 numbers $a_1,\cdots,a_{75},a_1+24,\cdots,a_{75}+24$. By the inequalities above, these numbers range from 1 to 149. Then, by the pigeonhole principle, at least two of them are equal (in a list of 150 integers ranging from 1 to 149, at least two are equal). Because all the numbers $a_1,\cdots,a_{75}$ are distinct, and all numbers $a_1+24,\cdots,a_{75}+24$ are also distinct, it follows that $a_i = a_j + 24$ for some $i > j$. Therefore, from the $(j+1)^{th}$ hour to the $i^{th}$ hour, there were exactly 24 competitions. Now, I will show the attempt at a solution for part 2: 2 - a) The same reasoning as above can be used: $1\leq a_1<a_2<\cdots<a_{75}\leq 125$. Adding 2 to all terms: $3\leq a_1 + 2<a_2 + 2<\cdots<a_{75} + 2\leq 127$ So, there are 150 numbers that range from 1 to 127. Therefore, by the pigeonhole principle, at least $\left \lceil \frac{150}{127} \right \rceil$ = 2 numbers must be equal. So, there is an $a_i = a_j + 2$. This guarantees that there is a period of consecutive hours during which there were exactly 2 competitions. b) The same reasoning as above can be used: $1\leq a_1<a_2<\cdots<a_{75}\leq 125$. Adding 23 to all terms: $24\leq a_1 + 23<a_2 + 23<\cdots<a_{75} + 23\leq 148$ So, there are 150 numbers that range from 1 to 148. Therefore, by the pigeonhole principle, at least $\left \lceil \frac{150}{148} \right \rceil$ = 2 numbers must be equal. So, there is an $a_i = a_j + 23$. This guarantees that there is a period of consecutive hours during which there were exactly 23 competitions. c) $1\leq a_1<a_2<\cdots<a_{75}\leq 125$. Adding 25 to all terms: $26\leq a_1 + 25<a_2 + 25<\cdots<a_{75} + 25\leq 150$ In this case, there are 150 numbers that range from 1 to 150. So, there are not necessarily two equal numbers. Therefore, we can't conclude anything directly. But it is possible to show that the statement is not true for 25, because an explicit counter-example (suggested below in the comments) can be found. Suppose the number of matches until each one of the 75 hours is, respectively: $\{1,2,\cdots,25,51,\cdots,75,101,\cdots,125\}$. Here, there are no pairs of numbers whose difference is 25. d) $1\leq a_1<a_2<\cdots<a_{75}\leq 125$. Adding 30 to all terms: $31\leq a_1 + 30<a_2 + 30<\cdots<a_{75} + 30\leq 155$ In this case, there are 150 numbers that range from 1 to 155. So, we can't apply the pigeonhole principle here, similarly to the above situation. It is not easy to find a counter-example in this case; I think that, for 30, the statement is always true (that is, there is always a period of consecutive hours during which there were exactly 30 matches). But I'm not sure how to prove it. Edit: I think I found a way to prove it, based on the suggestion given by Lopsy; I've included it as an answer to this question. Thank you in advance. |
The phrase "what language" in a title tends to be followed by one of: "is this?" (code snippet) "should I use for X?" "is X programmed in?" See , I'd argue that (1) does not demonstrate minimal understanding, or even a problem (2) is opinion-based (3) is a weird combination: does not demonstrate a specific problem in an off-site resource But, before I flag most of the ~400 (eventually), are these questions on-topic? | I found this question today: I wanted to ask a similar question about SAS. Knowing the academic classification of a language can greatly increase your ability to discover and apply various patterns and practices unique to that domain, and can also help when developing a curriculum (however small) to teach students and colleagues about the language. I'm hesitant to post my question, though. The example question above was fairly well received (+36/-2) but it's also 3 years old. I can't decide if this sort of question would currently be considered "on-topic". If I'm careful to phrase the question in terms of wanting an "academic" classification (not personal opinion), and ask that users explain what process they used to choose a proposed classification, would this kind of question even be answerable? Or are these questions inherently, invariably and unrecoverably opinion-based? (In my opinion, the example question above is kind of a bad example in that it was left very open-ended and the answers were way too short (as per ). The question has more to do with these kinds of question in general and not the example specifically.) |
I'm doing anomaly detection on unsupervised data using k-means I got a result but I don't know how to validate my clustering result. by plotting I can see my anomalies but how should I validate that clustering is accurate. in supervised learning, we use cross-validation like this any method or technique for unsupervised means. | One of the biggest issue with cluster analysis is that we may happen to have to derive different conclusion when base on different clustering methods used (including different linkage methods in hierarchical clustering). I would like to know your opinion on this - which method will you select, and how. One might say "the best method of clustering is which gives you the right answer"; but I may question in response that cluster analysis is supposed to be an unsupervised technique - so how do I know which method or linkage is the right answer? In general: is a clustering alone robust enough to rely on? Or we need a second method and get a shared result to be based on both? My question is not only about possible ways to validate / evaluate clustering performance, but is broader - on what basis do we select/prefer one clustering method/algorithm over another one. Also, is there common warnings that we should look around when we are selecting a method to cluster our data? I know that it is very general question and very difficult to answer. I only would like to know if you have any comment or any advise or any suggestion for me to learn more about this. |
I saw last week a presentation that was made with keynote and which was showing cells filled with speckled colours. Is there a way to get speckled colours in latex/beamer ? Until now I was only able to find uniform fills. greetings, yves SAM: I would like to see some granularity in my fill: | How to have a new recalculated random pattern? This one is the same translated everywhere. Edit I perfectly understand that the pattern is calculated once and drawn several times after. My question is, how to change this: use the mechanism of the pattern to paint an area with, but to force a recalculation of the pattern at each drawing. For an usual pattern it is useless, but in this case one could extract the code and switch the order and insert the pattern calculation and drawing inside the loop that fill the area: a sort of pattern-bis that one could use as normal pattern syntax. I don't know TeX programming enough to do that if it possible. Of course such a work will deserve a bounty ! \documentclass[tikz,margin=3pt]{standalone} \usetikzlibrary{patterns} \pgfdeclarepatternformonly{Rnd} {\pgfpointorigin}{\pgfpoint{1cm}{1cm}} {\pgfpoint{.5cm}{.5cm}} {\foreach \i in {1,...,100} {% \pgfpathcircle{% %\pgfpoint{.25cm}{.25cm}}{.4pt} \pgfpoint{rnd*.5cm}{rnd*.5cm}}{.25pt}} \pgfusepath{fill} } \begin{document} \begin{tikzpicture} \draw[pattern=Rnd] (0,0) rectangle (5,5) ; \end{tikzpicture} \end{document} |
Is $\mathbb{Z}[\sqrt{-7}]$ a UFD or not? I feel like there should be some easy example showing that it is not, but I can not think of one. | I'm considering the ring $\mathbb{Z}[\sqrt{-n}]$, where $n\ge 3$ and square free. I want to see why it's not a UFD. I defined a norm for the ring by $|a+b\sqrt{-n}|=a^2+nb^2$. Using this I was able to show that $2$, $\sqrt{-n}$ and $1+\sqrt{-n}$ are all irreducible. Is there someway to conclude that $\mathbb{Z}[\sqrt{-n}]$ is not a UFD based on this? Thanks. |
I have the following CSS .EggChart { width: 5000px; height: 400px; } and would like to read the value of height from the CSS class specification, either using raw JavaScript or in jQuery. If the class has been applied to an element of the DOM this seems straightforward: I'd select the elements of the DOM with this class and read their CSS attributes, but if the class has not been applied to any DOM element how would I do this? | I would like to return a string with all of the contents of a CSS rule, like the format you'd see in an inline style. I'd like to be able to do this without knowing what is contained in a particular rule, so I can't just pull them out by style name (like .style.width etc.) The CSS: .test { width:80px; height:50px; background-color:#808080; } The code so far: function getStyle(className) { var classes = document.styleSheets[0].rules || document.styleSheets[0].cssRules for(var x=0;x<classes.length;x++) { if(classes[x].selectorText==className) { //this is where I can collect the style information, but how? } } } getStyle('.test') |
I get this error when clicking "typeset" on TeXShop: "/usr/texbin/pdflatex does not exist. TeXShop is a front end for TeX, but you also need a TeX distribution. Perhaps such a distribution was not installed or was removed during a system upgrade. If so, go to and follow the instructions to (re)install MacTeX. A less likely possibility is that a tool path is incorrectly configured in TeXShop preferences. This can happen if you are using the macports or fink distributions." How do I fix this issue? (I apologize if the tag below is incorrect.) | Texstudio doesn't work for me anymore after updating to Mac OS X 10.11 El Capitan. I have the latest version of TexStudio installed (2.10.2). As pointed out by , this is due to a change in the places OS X allows files to be saved. When I started TexStudio, I received a message "PDFLatex could not be launched". In the settings, I had to change the folder of the compiler from user/texbin/ to /Library/Tex/texbin, as shown in the screenshot below: Can anybody tell me if I have to make further changes in order to make TexStudio fully working (bibliography and the like), and if yes, which? I hope TexStudio are very soon going to release an update (there is an issue for this on their issue queue. Thank you for your help. This is my first post here, so please apologize any imprecisions. |
Let $\mathcal{I}$ be a proper ideal of $\mathbb{F}[x]$ where $\mathbb{F}$ is a field. Show that there is a polynomial $P_0(x)\in \mathbb{F}[x]$ with degree larger than $0$ with the property that $$\mathcal{I}=\{P_0(x)\cdot q(x):q(x)\in \mathbb{F}[x]\}.$$ (In other words, prove there is a polynomial $P_0$ with the property that $\mathcal{I}$ consists precisely of the multiples of $P_0$.) Previously, I have proved Let $\mathbb{F}$ denote the field described the set $$\mathbb{F}=\{r+si: r,s\in \mathbb{Q}\}$$ (Here $i$ is the infamous element of $\mathbb{C}$ with $i^2=-1$.) Consider the function $\lambda: \mathbb{Q}[x] \to \mathbb{F}$ defined by $$\lambda(p)=p(i) \qquad \text{ for all } p\in \mathbb{Q}[x]$$ 1) Show that $\lambda$ is a ring homomorphism. 2) Show that the kernel of $\lambda$ is the set of all polynomials $p\in \mathbb{Q}[x]$ that are divisible by $x^2+1$. Proof of (i): For $\lambda$ to be a ring homomorphism, we need to show that > a) $\lambda(f+g)=\lambda(f)+\lambda(g)$ b) $\lambda(fg)=\lambda(f)\lambda(g)$ c) $\lambda(1)=1$ \textbf{\textit{Proof of a:}} Let $f,g \in \mathbb{Q}[x]$. Then we need to show that $\lambda(f+g)=\lambda(f)+\lambda(g)$. So $$\lambda(f+g)=(f+g)(i)=f(i)+g(i)=\lambda(f)+\lambda(g).$$ \textbf{\textit{Proof of b:}} Let $f,g \in \mathbb{Q}[x]$. Then we need to show that $\lambda(fg)=\lambda(f)\lambda(g)$. So $$\lambda(fg)=(fg)(i)=f(i)g(i)=\lambda(f)\lambda(g).$$ \textbf{\textit{Proof of c:}} Let $f=1 \in \mathbb{Q}[x]$. Then we need to show that $\lambda(1)=1$. So $$\lambda(1)=1(i)=1.$$ Hence $\lambda$ is a ring homomorphism. Proof of (ii): We need to show that the kernel of $\lambda$ is the set of all polynomials $p\in > \mathbb{Q}[x]$ that are divisible by $x^2+1$. Suppose $x^2+1|p(x)$. Then $p(x)=(x^2+1)g(x)$ for some $g(x)\in > \mathbb{Q}[x]$. Using part (i), we can show that $p(x) \in > ker(\lambda)$ (i.e. that $p(x)=0$): $$\lambda(p(x))=(x^2+1)g(x)=(i^2+1)g(i)=0\cdot g(i)=0$$ Hence we have show that $p(x)\in ker(\lambda)$. Suppose $p(x) \in ker(\lambda)$. Using the Euclidean division over $\mathbb{Q}[x]$ to divide $p(x)$ by $x^2+1$. We obtain: \begin{equation*} \begin{aligned} 0 & =\lambda(p(x)) \\ & > =\lambda(q(x)(x^2+1)+r(x)) \\ & =\lambda(q(x))\lambda(x^2+1)+\lambda(r(x)) \\ & =p(i)(i^2+1)+r(i) \\ & =r(i) \\ \end{aligned} \end{equation*} Hence we have show that the remainder is $0$, which implies that $p(x)=(x^2+1)g(x)$. Hence, the kernel of $\lambda$ is the set of all polynomials $p\in \mathbb{Q}[x]$ that are divisible by $x^2+1$. I know both proofs are related to one another. So what is needed to change in the previous proof for the new proof? | I am looking at and trying understand the proof for the theorem that states: Given a nonzero ideal I in $P(F)$, there is a monic polynomial $p(t)$ such that $$I=\left\{q(t)p(t) | q(t) \in P(F) \right\}$$ Proof goes like Since $I$ contains at least one nonzero element, we can let $p(t)$ be a nonzero element of $I$ of minimum degree. We can show that every element of $I$ is a multiple of $p(t)$. Let $f(t) \in I$. Then there exist $q(t),r(t) \in P(F)$ such that $$f(t) = q(t)p(t) + r(t)$$ and deg $r(t)$ < deg $p(t)$. Since $p(t) \in I$, so is $q(t)p(t)$, and therefore so is $$r(t) = f(t) -q(t)p(t)$$. By the choice of $p(t),r(t) = 0$, so $f(t)$ is a multiple of $p(t)$. What I am having trouble understanding is why $r(t)$ must equal $0$. If someone can explain why it is, I'd appreciate it. |
From the : The layer that is created by the tool is temporary and will not persist after the session ends unless the layer is saved to disk or the map document is saved. However, it does not state where this temporary location is. Is it the same as the that Esri suggests using while geoprocessing? | I was wondering the difference is between and using an ? To me, one can use either to do some steps in memory, instead of writing data to a location on disk or a network location, and expedite the process. |
I want clear one concept in AstroPhotography with an object in foreground. When I tried to capture the milky way with focus on infinity and 20 sec of exposure. I went pefect. But when I tried to capture the milky way with my friend holding torch in foreground, his picture was blurry everytime. Kindly help me out, how to take a person and milky way both in focus and clear, that too in one shot. I've attached a picture for example. Thanks n BR, Prashant | I went out and captured the Milky Way and because I have a 18mm-55mm 1: f3.5 5.5 lens I had to turn the camera sideways and stitch them together in photoshop and just having to work with what I got at the moment until I can afford something better but I was really happy with how it turned out! but I'd like to take it to the next step and maybe have a foreground or myself in the picture. So this brings me to the question, How do people capture the Milky Way/stars with themselves in it so clearly or sitting around the fire without it being over exposed. Is this through post processing and how do they do this, I can't necessarily completely understand how to do it. Such like these: |
I've made a nautilus short cut for almost all of my common folders. But when I press the keys to use the shortcut the folder do open, but they only open in the background. I still have to make a few clicks to see them infront of me. I want to configure my shortcuts so the nautilus folders show up on top of everything. How can I do that? Currently I am only using the basic System Settings keyboard shortcut function. | What is the shortcut for opening a new window (opening folders). for that I have to go to folder options and right click and then need to click on open new window. or I have to make focus on the folder icon or open a folder then press Ctrl+N for opening a new window is there any direct command spcific to open a new window in ubuntu. |
was recently caught plagiarising a significant number of answers on both Stack Overflow and on . Many of the plagiarised answers were deleted by a moderator. Apparently this user wanted to regain his lost rep so badly that he engaged in voting fraud, and had his answers serially upvoted to the point where he gained an association bonus for all of his Stack Exchange accounts on September 16th: The system reversed the serial upvotes, but it appears that his association bonus remains for his Stack Exchange accounts. The user's SO rep before his suspension totaled about 65 (minus the 100 bonus), while his rep on Share Point only totals 125 (again, not including the 100 bonus). Additionally, this user's was plagiarised, though a moderator recently edited it to include somewhat better attribution. Users should not retain association bonus from voting fraud It is my understanding that the association bonus well enough to be trusted with skipping new user restrictions on other Stack Exchange sites. However, this user has quite literally cheated his way to "earning" his association bonus. He did not, in fact, actually earn it. Yet the system appears to be letting him keep it. I was about to suggest a change in the system to allow moderators to revoke the bonus, but I suppose that this sort of thing happens infrequently, to the point where it's probably not worth the devs' time to implement such a moderator tool. Would it be possible to just make the appropriate change in the database manually, this one time? I considered the case that the retention of the bonus , but it does not appear that way to me. Related: . | When a user's rep gets bloated because of serial upvoting, and as result the user is given the association bonus, shouldn't that association bonus also be reversed in case of serial upvoting reversal? |
I have recently installed ubuntu in dual boot with windows 10 and everything was working, until I switched on the computer and ubuntu was 1024x768 instead of 1920x1080 and only one monitor was connected. How can I fix this? | As expected, Nvidia drivers have reduced my customizations. I can't login to Unity 3D session. I can't find any content to help me to uninstall the driver and I don't know what to do as I have never uninstalled them before. |
I have learnt that it states "The work done on a body is equal to the change in kinetic energy of the body" which we derived by considering a position-dependent force. However, if mechanical energy is not conserved and one can do work by friction forces, one can increase the internal energy of the body. From my understanding the work-energy theorem is thus not valid unless we consider the internal energy as kinetic energy. Is the work-energy theorem only valid for conservative, i.e. position-dependent forces? | How can the be valid in presence of non-conservative forces since conservation of energy is not there? |
Since gravity is several orders of magnitude weaker than the rest of the fundamental forces, the force of gravity acting on a single particle is almost *nonexistant. Since there is still a lot left for us to learn about gravity, is it possible that the force is fundamentally undetectable on a quantum scale? Does the Planck distance even correctly apply to this type of situation? | With the announcement of the detection of gravitational waves, questions about the implications proliferate. Some relate to the possible existence of gravitons. The analogous relationship between gravitons/gravitational waves and photons/electromagnetic waves is frequently mentioned. The detection of individual photons required experiments of very low intensity light, yet their existence was inferred (prior to their actual detection) by Planck and Einstein (among others) using the properties of experimental black body radiation and the photo-electric effect. If the prospects for detection of gravitons requires similar study of very low intensity gravitational waves, then those prospects are very dim indeed. My question: are there similar indirect "experimental" methods for inferring the existence of gravitons? |
I'm trying to get an obj model parsed for webGL content. I'm using Java Spring with thymeleaf and have my resource as an obj file in my resources/static/ folder. I need to get the contents of the obj file as a string to parse it in the javascript on the html web page and feed it into my WebGL, but I'm not sure on how to access it. Do I need to do an ajax html call to return the data as a JSON? Or is there a way of just accessing that resource from the URL similar to embedding an image on a webpage. I'm quite new to this web development business, so it might sound dumb but I am stuck here. Thank you. | I have a text file in the root of my web app and I'd like to load it into a variable in javascript.. in groovy I would do this: def fileContents = 'http://localhost/foo.txt'.toURL().text; println fileContents; How can I get a similar result in javascript? |
So when I am using cycles in blender, every time I use an image texture for this model's hair, it turns out like this. He is supposed to be completely blonde and no matter what I add or manipulate in the nodes, it doesn't change so there is always this black in his hair. Is there something I should be doing in particular or is it something else? Because it works for majority of the other models except a few that do the same thing, particularly the blonde ones or one's that have wavy hair. These are the textures used for this model's hair Thanks :) Btw I'm new to this site so sorry if I do something wrong! :/ Here I tried to duplicate the question "How can I setup a Material in Cycles for Z-Transparency?" and this is what I got. It's still not right. | After converting to nodes in order to render using Cycles I've no idea where to enable the z-transparency. I guess the image textures alpha channel needs to be pluged somewhere but I've no idea which node would be suitable. The question is how could I correctly setup the nodes to have the same effect as when using z-transparency in BI? The materials original settings for BI are: Which renders like: I had no luck with DarenWs suggestion: |
I own a laptop but without the battery (since I never used it, I gave it away). Since it is required to have a charged battery on some flights to the US, I was wondering how to bring my laptop to the US. Who should I contact to get an exemption? | According to some reports, your electronic devices are checked whether they turn on before you can get on a US bound flight. What if I carry around a laptop without a battery? |
note that this was part of a mega question split as requested I'm a film student working on a script on a Star Wars film as a personal project, I know there is little to no chance that I would ever get to work on a star wars film but we can dream. Anyway I would like some questions answered to help clarify how things work in the Star Wars universe. Any help would be appreciated. First Question: What is a Balance of the Force? Something I always found interesting was one of Spoony's old written reviews of Star Wars Episode III in which he makes a good point, how does wiping out the Sith bring balance to the force, surely all you’re doing by killing them is making the force more imbalanced as one side is vastly stronger than the other. Surely to get true balance, one must except both the Light and the Dark and be able to use them in harmony like how Luke did in episode 6. He was able to use deceit & truthfulness, Fear & Joy and most importantly, Anger and Compassion. This can be best seen in the final battle in the Death Star as he was able to use anger as a strength and then did not get consumed and used compassion, effectually using both sides of the force in balance. | The legend of the Chosen One foretold the coming of a being who would restore balance to the Force. Now we know that Anakin Skywalker was the Chosen One, but how exactly was he supposed to restore balance? Is a balance to the Force: eliminating all Dark Side users so that only the Light Side remains? reducing the Dark Side's influence to almost nothing, but still leaving some Dark Side users so that there is a balance of energies? (End of Episode VI, there are still Dark Side users in Legends) creating an equal presence on both sides? (for example, at the end of Episode III it appears that there are two Sith [Sidious and Vader] and two Jedi [Yoda and Obi-Wan]) Any other way not mentioned above? And whichever the legend means, has the prophecy been completed? Has the Chosen One restored balance to the Force at one point, or did he fail to fulfill the prophecy? So in short, What is the meaning of 'balance' when it is said that "The Chosen One will bring balance to the Force", and did he fulfill the prophecy? |
While executing the following code i gets this error "Late bound operations cannot be performed on types or methods for which ContainsGenericParameters is true." class Program { static void Main(string[] args) { MethodInfo MI = typeof(MyClass).GetMethod("TestProc"); MI.MakeGenericMethod(new [] {typeof(string)}); MI.Invoke(null, new [] {"Hello"}); } } class MyClass { public static void TestProc<T>(T prefix) { Console.WriteLine("Hello"); } } The above code is just a scaled version of the actual problem i am facing. Please help. | What's the best way to call a generic method when the type parameter isn't known at compile time, but instead is obtained dynamically at runtime? Consider the following sample code - inside the Example() method, what's the most concise way to invoke GenericMethod<T>() using the Type stored in the myType variable? public class Sample { public void Example(string typeName) { Type myType = FindType(typeName); // What goes here to call GenericMethod<T>()? GenericMethod<myType>(); // This doesn't work // What changes to call StaticMethod<T>()? Sample.StaticMethod<myType>(); // This also doesn't work } public void GenericMethod<T>() { // ... } public static void StaticMethod<T>() { //... } } |
In the Android app, I clicked the Achievements in the top bar. When I rotated my phone, the achievements disappeared ... sort of. It actually became transparent, so I saw my achievements and my search results at the same time. | I just noticed a bug in the Stack Exchange Android app. A question is displayed incorrectly if the Achievements drawer is already open when the app loads a question. It looks like this: To reproduce: Open the Stack Exchange app, and tap the Achievements icon from the top. Leave the app without closing, then try to open a question from external source (e.g. search result, web browser, or Hot Network Question widget) For reference, I'm running Android 5.1 on a Nexus 5, and the app version is 1.0.68. |
I installed SimpleScreenRecorder with command: $ sudo snap install simplescreenrecorder I then tried to configure a record session so that the output would be saved on a USB drive, but as soon as I try and access the /media folder for the Save As path, I get the following error: Having experienced the same issue with GIMP in an earlier post, I tried the following command (which worked for GIMP) to solve the problem: $ sudo snap connect simplescreenrecorder:removable-media However, that resulted in the following error message: error: snap "simplescreenrecorder" has no plug named "removable-media" Is it possible to have SimpleScreenRecorder output to removable media, or is there a technical barrier preventing this? Update: I find that SimpleScreenRecorder is now available to install from apt directly. So I removed the snap version: sudo snap remove simplescreenrecorder Then installed from apt: sudo apt install simplescreenrecorder The trust and permissions that come with being a core apt package means the application has access to removable media without further configuration. | I have Ubuntu 18.04 LTS installed. I inserted USB-flash to my laptop. It was automounted to /media/username/DISKLABEL and opened in Nautilus. I can read and write objects to it. How can I access it from the application, which is installed as Snap? I tried snaps of the following applications such as gedit, arduino-mhall119, organize-my-files. All them show me errors if I navigate to /media folder: Could not read the contents of Media Error opening the directory of '/media': permission denied Output of active Snap is below: $ snap interfaces | grep -v ".*-$" Slot Plug :browser-support organize-my-files :core-support core:core-support-plug :cups-control gedit :desktop gedit,organize-my-files :desktop-legacy gedit,organize-my-files :gsettings gedit,organize-my-files :home arduino-mhall119,gedit,organize-my-files :network arduino-mhall119,gedit,organize-my-files,pulsemixer :opengl organize-my-files :pulseaudio organize-my-files,pulsemixer :unity7 arduino-mhall119,gedit,organize-my-files :wayland gedit :x11 arduino-mhall119,organize-my-files,pulsemixer gnome-3-26-1604:gnome-3-26-1604 gedit gtk-common-themes:gtk3-themes gedit gtk-common-themes:icon-themes gedit gtk-common-themes:sound-themes gedit - arduino-mhall119:serial-port - gedit:avahi-observe - gedit:mount-observe Updates: connecting mount-observe to Gedit with snap connect gedit:mount-observe does not help. it seems that we need special Snap with support of interface. |
suppose $f(x,y)=\frac{|x|^a|y|^b}{|x|^c+|y|^d}$ and $a,b,c,d >0$ how would you show that if $\frac{a}{c} + \frac{b}{d} >1$ then $\lim\limits_{(x,y)\to(0,0)}\frac{|x|^a|y|^b}{|x|^c+|y|^d}$ exists and equals $0$? I've been trying to use the squeeze theorem and set up an inequality but im really struggling. | Ted Shifrin on this site posed an interesting problem to me: show that $$ \lim_{(x,y) \to (0,0)} \frac {|x|^ \alpha |y|^ \beta} {|x|^ \gamma + |y|^ \delta} \text {exists} \iff \frac\alpha\gamma + \frac\beta\delta > 1, \,\,\,\,\text{where } \alpha, \beta, \gamma, \delta >0$$ I think I've got the $(\Leftarrow)$ direction as follows: assume WLOG that $\gamma \leq \delta$. Then switch to polar coordinates and get $$\frac {r^ {\alpha + \beta} (*) } {r^\gamma (1(*) + r^{\delta - \gamma}(*))},$$ where $(*)$ represents some trig stuff that is bounded near zero. Edit: I need to make sure that $(1(*) + r^{\delta - \gamma}(*))$ is bounded below here. The other direction is giving me some trouble. It seems we need a lower bound for the fraction (something to force to zero), and I'm not sure where to find one. In particular, I'm not sure what to do with the denominator. Any ideas? |
Example XML using element nodes: <?xml version="1.0" encoding="utf-8"?> <users> <user> <name>David Smith</name> <phone>0441 234443</phone> <email>[email protected]</email> <addresses> <address> <street>1 Some Street</street> <town>Toy Town</town> <country>UK</country> </address> <address> <street>5 New Street</street> <town>Lego City</town> <country>US</country> </address> </addresses> </user> </users> Example XML using attributes: <?xml version="1.0" encoding="utf-8"?> <users> <user name="David Smith" phone="0441 234443" email="[email protected]"> <addresses> <address street="1 Some Street" town="Toy Town" country="UK" /> <address street="5 New Street" town="Lego City" country="US" /> </addresses> </user> </users> I'm needing to build an XML file based on data from a relational database and can't work out whether I should use attributes or elements. What is best practice when building XML files and why? | At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file. The sample I came up with is essentially something like: <INVENTORY> <ITEM serialNumber="something" location="something" barcode="something"> <TYPE modelNumber="something" vendor="something"/> </ITEM> </INVENTORY> The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested: <INVENTORY> <ITEM> <SERIALNUMBER>something</SERIALNUMBER> <LOCATION>something</LOCATION> <BARCODE>something</BARCODE> <TYPE> <MODELNUMBER>something</MODELNUMBER> <VENDOR>something</VENDOR> </TYPE> </ITEM> </INVENTORY> The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data. After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element? |
A covering space of a Hausdorff space is also Hausdorff. Conversely, a compact Hausdorff finite covering space has a Hausdorff base space. However, in general, a non Hausdorff space may have a Hausdorff covering space. Could someone give an example of the last? I can't find anyone. Thank you very much! | Let $\overline{X} \rightarrow X$ be a covering space, where $\overline{X}$ is a Hausdorff space. Does $X$ have to be Hausdorff? I assume there is a counterexample, but I couldn't find one yet. |
I have an entity Recipe, which besides all attributes also holds an attribute of java.sql.Timestamp corresponding to column date_created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP in my database. I understand that jpa is providing the database with a null value of Timestamp, but I cannot think of a fix. Ideally, when inserting a new recipe, jpa should not provide a non-null value for Timestamp, but rather let database give it the default value. Or atleast this is my idea. Any idea how to help me overcome with this error? Thank you | For a certain Hibernate entity we have a requirement to store its creation time and the last time it was updated. How would you design this? What data types would you use in the database (assuming MySQL, possibly in a different timezone that the JVM)? Will the data types be timezone-aware? What data types would you use in Java (Date, Calendar, long, ...)? Whom would you make responsible for setting the timestamps—the database, the ORM framework (Hibernate), or the application programmer? What annotations would you use for the mapping (e.g. @Temporal)? I'm not only looking for a working solution, but for a safe and well-designed solution. |
How do I use regex to get what is inside of a ${} enclosed value such as: Dont care about this. ${This is the thing I want regex to return} Not this either. Should return: This is the thing I want regex to return I've tried \${ }$ the best I got messing around on regex101.com I'll be honest I have no Idea what I'm doing as far as regex goes using on c++ but would also (if possible) like to use in geany text editor | Unfortunately, despite having tried to learn regex at least one time a year for as many years as I can remember, I always forget as I use them so infrequently. This year my new year's resolution is to not try and learn regex again - So this year to save me from tears I'll give it to Stack Overflow. (Last Christmas remix). I want to pass in a string in this format {getThis}, and be returned the string getThis. Could anyone be of assistance in helping to stick to my new year's resolution? Related questions on Stack Overflow: |
I have a vague memory about a TV series I saw as a kid (mid-late 1990's). It was about a male teenager, traveling alone, who had time travel adventures. I loved it to bits, but I haven't seen or heard of it since. It would have been in English. Anyone know what I'm talking about? I don't remember any further details, but I'm hoping someone remembers it. I'm a big fan of time travel, so hate to miss out on decent time travel stuff. | In the 1980/90s there was a TV show airing in the Eastern USA about two partners who had this pocket watch that was actually a time machine. I distinctly remember an episode where the two time traveled to Thomas Edison's time and met him. Mr. Edison pick pocketed the watch and completely disassembled it to see how it worked. Panic ensued till he was able to reassemble it. Apparently in the the process it taught Mr. Edison how a light filament works and was the catalyst for him inventing the light bulb. Anyone know what this series was called? |
I am using 3rd party library, and there is specificly a method that I want to shim. public virtual QueueRuntimeInfo GetQueueRuntimeInfoAsync(string queuePath); This method return QueueRuntimeInfo object. Here is the implementation of that class, which there is no constructor: public class QueueRuntimeInfo { internal QueueRuntimeInfo(string path) { this.Path = path; } public string Path { get; internal set; } public long MessageCount { get; internal set; } } Now, I want to shim GetQueueRuntimeInfoAsync method, which return QueueRuntimeInfo object, and then I want to set its property manually in my code. Here is my shim method: ShimManagementClient.AllInstances.GetQueueRuntimeInfoAsyncString = (managementClient, queuePath) => { QueueRuntimeInfo queueRuntimeInfo; // what to do?! return queueRuntimeInfo; }; I think I can shim get methods of QueueRuntimeInfo class (PathGet and MessageCountGet). But still need to create the object somehow. | Take the following class as an example: class Sometype { int someValue; public Sometype(int someValue) { this.someValue = someValue; } } I then want to create an instance of this type using reflection: Type t = typeof(Sometype); object o = Activator.CreateInstance(t); Normally this will work, however because SomeType has not defined a parameterless constructor, the call to Activator.CreateInstance will throw an exception of type MissingMethodException with the message "No parameterless constructor defined for this object." Is there an alternative way to still create an instance of this type? It'd be kinda sucky to add parameterless constructors to all my classes. |
I have some bunch of points in an area and I want to draw connecting lines with the help of points to create a closed polygon. But all these needs manual efforts. Can any one explain to me how to create polygon automatically in QGIS with the help of outermost points. | I want to know if there is a plugin in QGIS, which will allow me to draw the outline a point cloud. I know there Points2One the plugin, but it makes an outline with all points, even with the data found in the middle of the point cloud. I give you an example ; x y ID order 3.3 43.2625 353293 1 3.13334 43.3458 353293 2 3.21667 43.3458 353293 3 2.88334 43.4292 353293 4 2.96667 43.4292 353293 5 3.05 43.4292 353293 6 3.13334 43.4292 353293 7 2.71667 43.5125 353293 8 2.8 43.5125 353293 9 2.88334 43.5125 353293 10 2.96667 43.5125 353293 11 3.05 43.5125 353293 12 3.13334 43.5125 353293 13 2.88334 43.5958 353293 14 2.96667 43.5958 353293 15 3.05 43.5958 353293 16 3.13334 43.5958 353293 17 2.96667 43.6792 353293 18 3.05 43.6792 353293 19 3.13334 43.6792 353293 20 3.21667 43.6792 353293 21 3.05 43.7625 353293 22 3.13334 43.7625 353293 23 3.21667 43.7625 353293 24 3.13334 43.8458 353293 25 3.21667 43.8458 353293 26 With the tool suggested by @ArMoraer I can only draw a polygon with the outer points that are more extreme. The polygon has touched just 5 points (see map of Convex hull below) but normally it should pass on 20 points (all points of the contour). Each point has a pixel, actually the outline should not touch the points but it must pass through the outer limit of these pixels. In the end I want to have an outline like this map (see map below : desired contour) |
The question first asks to show that $\sqrt{3}$ has a root in $\mathbb{Q}(\sqrt{3})=\{a+b\sqrt{3}|a,b \in \mathbb{Q}\}$ but not in $\mathbb{Q}(\sqrt{2})$. This is I solved by assuming, towards a contradiction, that $\exists a,b\in \mathbb{Q}$ such that $a+b\sqrt{2} = \sqrt{3}$, so $b = \frac{\sqrt{3} - a}{\sqrt{2}}$. Clearly this is a contradiction since $\frac{\sqrt{3}}{\sqrt{2}}$ is irrational, and $\frac{a}{\sqrt{2}}$ is either zero or irrational, so their difference must be irrational. Then the queestion asks me to explain why this implies that $\mathbb{Q}(\sqrt{2})$ is not isomorphic to $\mathbb{Q}(\sqrt{3})$. In previous questions, I showed that $\mathbb{Q}(\sqrt{2})$ is isomorphic to $\mathbb{Q}[x]/\mathopen{<}x^{2}-2\mathclose{>}$, where the latter is the set of congruence classes modulo $x^2 - 2$, and the same for root 3. I'm guessing that we come to some contradiction if we assumed that a field not containing $\sqrt{3}$ is isomorphic to $\mathbb{Q}[x]/\mathopen{<}x^{2}-3\mathclose{>}$, but I don't see how. Any hints or suggestions would be appreciated. Thanks! | In this we saw isomorphism of vector spaces over $\mathbb{Q}$. Just came across this question: Is $\mathbb{Q}(\sqrt{2}) \cong \mathbb{Q}(\sqrt{3})$? I know these as $\mathbb{Q}$-Vector spaces, are isomorphic from the linked post. But as fields are they isomorphic? I neither know how to prove it nor how to disprove it. |
Is it true that $$\int_{\Bbb R} G(x)dF(x) + \int_{\Bbb R} F(y)dG(y) = 1$$ where $F$ and $G$ are distribution functions of $X$ and $Y$ such that both have no common jump points i.e. $P(X=Y) = 0$ ? How to prove it ? I am unfamiliar with Stieljes integral | Suppose that $X$ and $Y$ are random variables with distribution functions $F$ and $G$. If $F$ and $G$ have no common jumps then I need to show that $E[F(Y)] + E[G(X)] = 1$. How to proceed here ? Shall I try to show that the LHS is some probability of almost sure events or product of two almost sure events. Clearly, $F(Y)$ and $G(X)$ are random variables with range in $[0,1]$. |
Is there any managed API (C#) I can use to make screen captures, similar to what fraps does? Some possible things I'd like to do with it: Capture the whole screen (basic). Screen capture of full screen application. Screen capture of currently active window. Capture video of screen. | I want to capture the screen in my code to get an image - like using the 'print screen' button on the keyboard . Does anyone have an idea how to do this? I have no starting point. |
Does $|x_k|$ $\to$ $0$ and $\sum_{k=1}^{\infty} |x_k| < \infty$ $\implies$ $\sum_{k=m+1}^{\infty} |x_k| \to 0$ as $m\to\infty$ ? If so, how would one formally prove this? Any help would be greatly appreciated. | Let $x_n$ be a sequence of real numbers. Show that if $\sum_{n=1}^{\infty}x_n $ converges, then $\lim_{n\rightarrow\infty}\sum_{k=n}^{\infty}x_k=0.$ This is what I have done. We have by the Cauchy Criterion, for every $\epsilon>0$ there is an $N\in\mathbb{N}$ such that $n\ge N \ \implies |\sum_{k=n}^{\infty}x_k|<\epsilon.$ Taking the limit as $n \rightarrow \infty$ we get the desired result. Are there any problems with my proof? |
This is an old topic but I see there is an influx of new questions on SE which would be resolved by a bit of googling and some thought. Presumably this is due to the new academic year up in the northern hemisphere. Would a dedicated site to migrate homework questions to be a useful solution? It would also give lecturers/teachers a place to find who has been getting their homework done for them without having to trawl the internet | Since the would it make sense to create a Stack Exchange site dedicated to homework help? It wouldn't have to be limited strictly to homework either, possibly including discussions of puzzles and brain teasers and possible approaches to solving them. I have a programming background so I would be interested in helping with CS or math related homework, discussions of programming contest problems, etc. Topics don't necessarily have to be related to programming either. That's just where my interests are. What are your thoughts? |
Be a continuous function $f: \mathbb{R} \to \mathbb{R}$ such that $f(x)f(f(x)) = 1$ and $f(2020) = 2019$. What is the value of $f(2018)$? I am having a problem with this question. I already tried, through various attempts, to find the function explicitly which satisfy this condition and $f(0)$ different from $0$. But it leads me to nothing. I am really thinking there is no way to find an explicit function, so I would appreciate any solution to this problem (normally I would prefer a tip, but my ideas are exhausted). | If $f$ is continuous real function such that $f(11) = 10$ and $\forall x, f(x)f(f(x)) = 1$, then $f(9) =$ ? |
I’ve tried resetting it a few times with suggestions and instructions I found here and elsewhere on the web. I keep getting stuck because I don’t know his username. From what I can tell, what I thought was the username isn’t working in my attempt to reset the password. | I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there. I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution? |
I am able to display posts ordered by custom meta key using the pre_get_posts action. How ever, it is leaving out (not displaying) posts without this meta key. Is there any way to display the posts with out the meta key at the end? $q->set( 'meta_key', '_1m_e_date' ); $q->set( 'orderby', 'meta_value' ); $q->set( 'order', 'ASC' ); Thank you | I'm working on a custom taxonomy term page template where we want the items that are connected to the term sorted by a publication date (custom date field) - and if there are multiple items on the same day (formatted like YYYY-MM-DD) to then sort those by title, and finally sort by title if the custom field has not been filled out (older items). So, I tried it hundred different ways with a WP_query and it does return most of the results as I want them - but in this case it's only returning the items that have the meta_key of publication_date. All other items are being ignored and not displayed. I tried a meta_query using a relation of "or" and compared the publication_date as EXISTS and NOT EXISTS, but that returned 0 results for me. Also, the site is running 3.5.2 still and they do not want to upgrade. Here is my most recent query that gets me the posts that have the publication_date custom field displayed in the correct order: $term = get_queried_object(); // find the term of the taxonomy page we are on $wp_query = new WP_Query( array( 'post_type' => 'resource', 'tax_query' => array( array( 'taxonomy' => 'resource_types', 'field' => 'slug', 'terms' => $term->name, )), 'meta_key' => 'publication_date', 'orderby' => 'meta_value_num', 'order' => 'DESC', 'paged' => $paged, 'posts_per_page' => '10', )); I also tried using wpdb and running a SQL query, but I really am not sure how to accomplish what I want doing that. If someone could help me out that would be awesome! Thanks in advance. |
I wonder if there is a test for comparing means of two different time series (both measured at the same person or two different persons)? Would be very glad if someone can help me! | I have two time series, shown in the plot below: The plot is showing the full detail of both time series, but I can easily reduce it to just the coincident observations if needed. My question is: What statistical methods can I use to assess the differences between the time series? I know this is a fairly broad and vague question, but I can't seem to find much introductory material on this anywhere. As I can see it, there are two distinct things to assess: 1. Are the values the same? 2. Are the trends the same? What sort of statistical tests would you suggest looking at to assess these questions? For question 1 I can obviously assess the means of the different datasets and look for significant differences in distributions, but is there a way of doing this that takes into account the time-series nature of the data? For question 2 - is there something like the Mann-Kendall tests that looks for the similarity between two trends? I could do the Mann-Kendall test for both datasets and compare, but I don't know if that is a valid way to do things, or whether there is a better way? I'm doing all of this in R, so if tests you suggest have a R package then please let me know. |
I would like to do a proof by induction. I know there's a few duplicate posts about this question but I dont quite understand the notation they have given while showing an induction proof. If someone could post an induction proof without any complex notation for the product of n consecutive integers, I would really appreciate it. - this answer, how does $(𝑚+1)(𝑚+2)...(𝑚+𝑘+1) = (k+1) (m+1)...(m+k) + m^{k+1}$ Can anyone expand this notation to show me whats happening? | How can we prove that the product of $n$ consecutive integers is divisible by $n$ factorial? Note: In this and the comments here the OP has clarified that he seeks a proof that "does not use the properties of binomial coefficients". Please post answers in said newer thread so that this incorrectly-posed question may be closed as a duplicate. |
I am writing a resume using the scrartcl,currvita, and classicthesis packages. Everything else is fine but I have run into a problem correctly justifying some dates along the right side of the page. When I use the command '\NewEntry', as defined below, it leaves a small white space of about 0.5em at the right side of the page, even though I have used /hfill. If I add the line manually instead of using a function, it does not do this, as shown in the picture. I have attached all of the code that I think is relevant. Can someone explain to me why it is doing this? Obviously I could just hand code it every time or correct it with /hspace(-0.5em) but I would much prefer to use a function. \documentclass[11pt]{scrartcl} \reversemarginpar % Move the margin to the left of the page \usepackage[nochapters]{classicthesis} \usepackage[LabelsAligned, NoDate]{currvita} \usepackage{marginnote} \usepackage{color} \usepackage[letterpaper,top=0.35in, bottom=0.15in, left=1.5in, right=0.5in,marginparwidth=1in,marginparsep=0.25in]{geometry} \newcommand{\NewEntry}[2]{\raggedright\noindent\hangindent=2em\hangafter=0 \textsc{\bf#1} {\hfill\small\textit{#2}} % Define a command for each new block - change spacing and font sizes here \vspace{0.15em}} % Add some white space after each new entry \begin{document} \pdfpageheight 11in \pdfpagewidth 8.5in \thispagestyle{empty} % Stop the page count at the bottom of the first page \begin{cv}{} --------------- \NewEntry{University of the Pacific}{Expected May 2016} \raggedright\noindent\hangindent=2em\hangafter=0 \textsc{\bf University of the Pacific} \hfill {\small\textit{Expected May 2016}} \end{cv} \end{document} | I found two things peculiar in the common style of macro definitions: Ending lines in macro definitions with '%'; Not wrapping a macro name in braces. Example: \newcommand\examplemacro{% \somecommand% \othercommand% } Being a software engineer first and a LaTeX user a distant second, I would expect: \newcommand{\examplemacro}{ \somecommand{} \othercommand{} } Is there a reason for doing it the former way, or is it merely a matter of habit? |
I found this interesting function defined by the following infinite series: $$g(x)=\sum_{n=0}^\infty(-1)^nx^{2^n}$$ And I noticed that it followed the functional equation $g(x)=1-g(x^2)$. I was interested, particularly, in the following limit: $$L=\lim_{x\to1^-}g(x)$$ And assuming it exists, the functional equation yields $$L=1-L\implies L=\frac12$$ Which, at first look, the limit appears to exist. However, upon closer inspection, convergence gets a little sketchy... Can we determine if the limit converges? | I want to calculate the limit of this sum : $$\lim\limits_{x \to 1} {\left(x - x^2 + x^4 - x^8 + {x^{16}}-\dotsb\right)}$$ My efforts to solve the problem are described in the . |
I’m going to Canada and my passport will expire in five months. Will this be OK? I cannot find the answer. I know some countries require it to be no more than six months before expiration. But I know some countries have different rules | I am traveling from Boston to Canada by cruise ship. The first port of arrival is on July 30 and the last port in Canada is on August 4. Then I'm flying on August 5 from Montreal to California. My passport is valid until August 20th. Will I have a problem? |
I'm writing an ObjectHasValueConverter : IValueConverter for WPF. The relevant function is Convert(object value, ...). I want essentially want to do return value != default(value.GetType()) Unfortunately, it seems default is a compile-time keyword and IValueConverter doesn't have a generic equivalent, so I can't just do default(T). Obviously if value is an instance of a class or an array I can just check for null. if (value.GetType().IsValueType | value.GetType().IsArray) { return value != null; } I have a special case for strings, returning !string.IsNullOrWhitespace(value). For structs and other primitives, I'm hoping there's something cleaner than if (value is int | value is short | value is long | ...) { return (int)value != 0; } if (value is float | value is double) { return (double)value != 0; } if (value is bool) { return !(bool)value; } ... I've scoured SO before writing this, but all the answers I found had to do with reflection and getting the members of a value type. I didn't find anything relating to types that are put on the stack. | I'm using reflection to loop through a Type's properties and set certain types to their default. Now, I could do a switch on the type and set the default(Type) explicitly, but I'd rather do it in one line. Is there a programmatic equivalent of default? |
I need several enderpearls to create Eye of Enders for portal I found (to open the end portal). However, I am having a hard time farming endermen due to them being scarce and the drop rate of enderpearls. Is there an efficient way to farm enderpearls? | I'm playing vanilla Minecraft, and am getting ready to head to the end. I need Eyes of Ender (and hence Ender Pearls), and in my main hunting grounds (a large desert area) as little as one Enderman may spawn per night. Is there any way to "promote" Enderman spawning so I can get pearls more quickly? |
I had studied the damped forced vibration and had come to know that the angular speed of force which creates resonance is Which is counter-intuitive to me that the angular frequency should match with the damped frequency so that the force is in phase with the motion. Therefore I am confused of the reasons behind this, I know how to differentiate a function, yet I cannot come up with a reasonable interpretation. | Consider a forced, damped harmonic oscillator $$\ddot{\phi} + 2\beta \dot{\phi} + \omega_0^2 \phi = j(t) \, .\tag{1}$$ If I pick a sinusoidal driving force $j(t) = A \cos(\Omega t)$, I find $$\phi(t) = \text{Re} \left[ e^{-i \Omega t} \frac{-A}{\Omega^2 - \omega_0^2 + 2i\beta \Omega} \right] \, .\tag{2}$$ From here, how do I define the ? Is it the point where $\langle \phi(t)^2 \rangle$ is maximized? Things I do know: The frequency at which $\langle \phi(t)^2 \rangle$ is maximized is $$\omega_r ~:=~ \omega_0 \sqrt{1 - 2(\beta/\omega_0)^2},\tag{3}$$ but I thought I read/heard that the resonance frequency of a damped oscillator is just $\omega_0$. I also calculated that the free oscillation frequency is $$\omega_{\text{free}} ~:=~ \omega_0 \sqrt{1 - (\beta / \omega_0)^2},\tag{4}$$ but I don't think that's the same thing as the resonance frequency under steady driving. |
Currently I'm using Ubuntu 12.04. I would like to upgrade to 14.04. Should I backup some important such as those of the web root folder ? If I would need so, how should I proceed ? | What are the different ways I can use to upgrade Ubuntu from one release to another? |
I'm getting error while running the following query. I think it's the proper syntax. Please help. SELECT * from TESTTABLE1 ORDER BY USER_ID WHERE rownum>=100 AND rownum<=200 | Is there a way to make an Oracle query behave like it contains a MySQL limit clause? In MySQL, I can do this: select * from sometable order by name limit 20,10 to get the 21st to the 30th rows (skip the first 20, give the next 10). The rows are selected after the order by, so it really starts on the 20th name alphabetically. In Oracle, the only thing people mention is the rownum pseudo-column, but it is evaluated before order by, which means this: select * from sometable where rownum <= 10 order by name will return a random set of ten rows ordered by name, which is not usually what I want. It also doesn't allow for specifying an offset. |
Find an infinite group in which every element $g$ not equal to $e$ has order $2$. In this case $e$ is the identity element. I have tried so many times but i can't really seem to understand what the question wants. Can someone please help me out in solving this question. | Find an infinite group, in which every element g not equal identity (e) has order 2 Does this question mean this: the group that fail condition (2) which is no inverse and also that group must have the size 2 My answer: Z* |
$$\int_{0}^{+\infty}\frac{\sin x}{x}dx$$ My start: Zero is a singular point, Let's define $g(z):=(e^{iz})\big/z$ $$\int_{\Gamma}\frac{e^{iz}}{z}dz=\\ \int_{-R}^{-r}\frac{e^{ix}}{x}dx+\int_{C_r^+}\frac{e^{iz}}{z}dz+\int_{r}^{R}\frac{e^{ix}}{x}dx+\int_{C_R^+}\frac{e^{iz}}{z}dz$$ $$=\int_{r}^{R}\frac{e^{ix}-e^{-ix}}{x}dx+\int_{C_r^+}\frac{e^{iz}}{z}dz+\int_{C_R^+}\frac{e^{iz}}{z}dz$$ from here I'm stuck the final answer should be $\pi /2$ $$(*)\lim\limits_{r\to 0}\int_{C_r^+}\frac{e^{iz}}{z}dz$$ $$(**)\lim\limits_{R\to 0}\int_{C_r^+}\frac{e^{iz}}{z}dz$$ | How can I calculate $$\int_0^\infty\frac{\sin x}xdx$$ by integration of a suitable function along the following paths: where $R$ and $\varepsilon$ are the radius of the shown outer and inner semicircle, respectively. This seems to be quite interesting. How would one do that? |
Prove that $\binom{n}{0}+\binom{n}{2}+\binom{n}{4}+...=\binom{n}{1}+\binom{n}{3}+\binom{n}{5}+...$ using a combinatorial approach, NOT an algebraic approach. Fot values of $n$ which are odd this is simple, using Pascal's identity and/or Pascal's triangle, but I am not sure how to approach this for even values of $n$. Thank you for your help. | What number do I get if I subtract the binomial coefficients $n\choose k$ with an even $k$ from those with an odd $k$, where $n$ is fixed? Am I supposed to subtract a binomial coefficient with an even $k$ from one with an odd $k$ and say what the number you would get or how exactly does this work? |
How can you find the top journals in a scientific field? I am an HCI graduate student, but I sometimes write to industrial engineering articles if it involves ergonomics. Right now, I'm trying to understand what standing the journal "IIE Transactions" has compared to other journals in the field of industrial engineering. I was told that the impact factor is not a good indicator to find top journals. What other indicators are useful for identifing top journals within specific fields, like industrial engineering? | A colleague and I recently submitted a paper to a journal with an impressive-sounding name, the "International Journal of Artificial Intelligence and Computational Research". According to , IJAICR is a referred [sic] journal in the field of computer science, artificial intelligence and soft computing methods. It was accepted two days after we submitted it. That's too fast. We were suspicious. Although the journal said that all papers are peer-reviewed, we could not see how that was done in two days. Plus, we received no comments from the reviewers. Also, the submission guidelines didn't ask for a "blind" copy (without our names or any references to who we were). But wait, there's more. The acceptance letter asked us to send them US$300 to publish it. We did not. We've withdrawn our submission and will submit a new version of the paper to a more reputable journal in the coming months. How might we make a better choice of respectable journals before we submit next time? |
Find $S$ if $S=\tan^21^\circ+\tan^23^\circ+\tan^25^\circ+\dots+\tan^289^\circ$. I tried converting all tangents above $45^\circ$ to cotangents and added them with tangents with the same angle, but that does not give any result nor does it telescope. Tried writing $\tan^2\theta = 1-\frac{\tan\theta}{\tan2\theta}$, but again, no headway. I am trying to relate this problem with complex numbers, and saying roots of a polynomial are of the form $\tan[(2n+1)\frac{\pi}{180}]$, but haven't been able to do so. | Problem: Find the value of $$\sum_{r=0}^{44} \tan^2(2r+1)$$ Note: The angles here are in degrees. I don't know how to solve this question because trigonometric simplifications didn't get me anywhere. I think there was a method to solve this question using complex numbers which I no longer remember. Any hint/help will be appreciated. |
I am a Sri Lankan and I work in Israel. I will be applying for schenegan visa from Israel. I would like to know is it possible by Schengen visa to travel by Eurostar to London from Paris? Do I need uk visit visa also? | I am planning a trip to France and other Schengen countries. First point of entry will by France. I am from South africa. Can I visit from France, with a Schengen visa from there the UK? Can I apply on that side, or do I have to apply in my own country first? |
I recently susccesfully ran a watershed delineation model using both ArcHydro Tools for Arc GIS 10.0 and Model Builder in ArcGIS 10.0 on Windows 7 system (Dell Inspiron N4110 Intel Core TM i3 CPU @ 2.30 GHz 64 Bit.) However when I try to run the same model on an XP computer (Intel Pentium 4 CPU @ 2.53 GHz 32 Bit) I received several run time errors such as: Error HRESULT E_FAIL has been returned from a call to a COM component. Fail to execute (Catchment Polygon Processing)" and also other like Drainage Point.. All the inputs are not current Adjoint Catchment All the inputs are not current I try also to build the same model from the scratch in this later system and I received the same type of run time errors. I'd be pleased to receive any clue to fix this problem. | I am trying to run a function from in ArcMap 10.1; Sink evaluation. But before it can finish it returns an error message, that, frankly, I don't understand at all. It goes System.runtime.interopservices.comexception (0x80004005): error hresult e_fail . Can anyone help me solve this? I have tried all I can think of. Run the function from the toolbox instead of dropdown menus, shorten paths, restart ArcMap, reinstall AHT, open new map documents, restart my computer, wait till next day and see if it automagically have fixed itself... After searching this forum I found a , although it's got no answers. Now I'm all out of ideas, can anyone please help me?! I'm using ArcMap 10.1 SP1 basic license and Windows 7. I think I have narrowed it down a bit, still not clear what's wrong though. Sink evaluation uses a series of functions in Arcmap, of which one is Zonal statistics as table. That's the one it gets stuck on. The input raster somehow does not exist, path unknown. I guess this is some intermediary raster. After consulting the Arc Hydro team, I got the advice not to use grids stored in a gdb (which I didn't). I have also tried to change target locations, thanks to @G.Oxsen. Unfortunately neither of those solved the issue. According to the Arc Hydro team, GPL0 that I asked about earlier is an in-memory grid, so probably no problem there. I am currently pursuing that it is related to the installation of SP1. Anyone out there using AHT with SP1 and got Sink evaluation working? Uninstalling SP1 did not change anything, unfortunately. Still working on this, but with less intensity. Seems like I'll have to find workarounds... By reducing the number of sinks in need of processing I managed to get Sink evaluation running. Having the files not stored in a gdb seem to help as well, as mentioned earlier, and using integer grids. Changing the "Maximum number of unique values to render" in ArcMap Options (Customize menu), tab Raster --> Raster dataset is another tip that I got (from the Arc Hydro Team). Restarting ArcMap after running every one or two functions also helps keeping things stable. |
I’m reading a manual right now instructing one to “press” the enter key. However, both press and depress appear to be correct, as explained in the question Click “submit” or press the enter key. Click “submit” or depress the enter key. I know that depress is the less commonly used one of these two, at least as a verb). But technically speaking, which is the more correct word to use? | In several books that mention GUI, keyboard, or mouse buttons (e.g. the book Programming Windows by Charles Petzold), the authors refer to the state of a pressed button as depressed. Why is this term used instead of the word pressed, which has a simple and intuitive meaning? Some alternative terms that could be a better fit are pushed, clicked, or activated. As someone who is not a native-English speaker, the term depressed is unintuitive to me because it resembles the opposite meaning: not pressed. |
$$\int_0^1 \prod_{n\geq 1} (1-x^n) \, dx = \frac{4\pi\sqrt{3}\sinh(\frac{\pi}{3}\sqrt{23})}{\sqrt{23}\cosh(\frac{\pi}{2}\sqrt{23})}$$ This monstrous expression is from Tolaso Network (tolaso.com.gr). I have no idea how to approach it - converting the product to a sum of logarithms does no good, and one cannot switch the order of product/integral either. The product in itself doesn't converge to anything nice either. I am interested in seeing the proof of the above identity, as well as an explanation of how exactly $\sqrt{23}$ becomes involved in such a deceptive integral. Both real and complex analytic solutions are welcome. A proof without the pentagonal number theorem would be nice as well, since that somewhat trivializes the problem. | Prove $$\int_0^1\prod_{n=1}^\infty(1-x^n)dx=\frac{4\pi\sqrt3}{\sqrt{23}}\frac{\sinh\frac{\pi\sqrt{23}}3}{\cosh\frac{\pi\sqrt{23}}2}.$$ In fact, product $(1-x^n)$ is difficult to compute, I hope you can show me some ideas, thank you! |
Here is my desktop entry to run "PRGM.sh" [Desktop Entry] Encoding=UTF-8 Name=PRGM Comment=Launch PRGM Exec=gksu /home/markku/PRGM.sh Icon=utilities-terminal Type=Application Terminal=true The program runs in terminal and at the end outputs a code I want to check. But the desktop entry runs the program in terminal and closes when it finishes so can't check the code. How can I modify the desktop entry to not close the terminal after execution? (It is required to use gksu) | I have the following shortcut which opens an SSH instance. How can I modify it so that when SSH closes, the terminal stays open? [Desktop Entry] Terminal=true Type=Application Name[en_US]=ssh Icon=/logo_sprite.png Exec=gnome-terminal --geometry=... --window-with-profile=... --title=... -e 'bash -c "ssh -t -i ~/dsa.key [email protected] sudo -s"' |
I'm trying to create a form that allows user to edit the input through new window. PHP will process the input then append the new input with the new values. Apparently, when I try to edit the appended input, the JavaScript just won't fire. Please enlighten me on what I did wrong. This is my html code: <html> <head> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <script> $(document).ready(function(){ $('.races').click(function(e){ console.log("Inside Testing"); e.preventDefault(); var currID = this.id; var content = '<form id="theForm" action="ct.php" method="post"> Race: <input type="text" id="race" name="race"><button type="submit" onClick="OKClicked()">Click this!</button></form>'; childWin = window.open('', "_blank", "height=400, width=550, status=yes, toolbar=no, menubar=no, location=no,addressbar=no"); toBeAdded = $(this).closest('div'); childWin.document.close(); childWin.document.write(content); popupRace = childWin.document.getElementById("race"); parentRace = document.getElementById(currID); transferValues(); }) }); function transferValues() { popupRace.value = parentRace.value; } function setValue(text) { childWin.close(); toBeAdded.parent().append(text); toBeAdded.remove(); } </script> </head> <body> <div> Name: <input type="text" name="name"> </div> <div> <div> <input type="hidden" name="race-0" value="Human" id="race-0"> <span>race: Human</span> <a href="javascript:void(0)" class="races" id="race-0">Edit</a> </div> </div> <div> Name: <input type="text" name="name"> </div> <div> <div> <input type="hidden" name="race-1" value="God" id="race-1"> <span>race: God</span> <a href="javascript:void(0)" class="races" id="race-1">Edit</a> </div> </div> </body> </html> And this is my php code: <?php $postDataKey = array_keys($_POST); $text = ""; foreach ( $postDataKey as $currPostKey ) { $currValue = $_POST[$currPostKey]; $text .= '<div><input type="hidden" name="'.$currPostKey.'-1" value="'.$currValue.'" id="'.$currPostKey.'-1"><span>'.$currPostKey.': '.$currValue.'</span> <a href="javascript:void(0)" class="races" id="race-1">Edit</a></div>'; } echo ' <html> <head> <script> window.opener.setValue(\''.$text.'\'); </script> </head> </html> ' ; ?> | I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off. This happens on page ready and works just fine. The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound. I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option. |
First of all, sorry for catchy title, my question is not that broad as it suggests. I just came to conclusion that I don't need parametric tests. Instead, I need some feedback if my reasoning makes sense. Here it is: To use some parametric test (like t-test or ANOVA), we have to check assumptions of it (normality, heterogeneity of vaiance). But all the tests for assumptions (Shapiro-Wilk, Kolmogorov-Smirnov, Anderson-Darling, Bartlett, Snedecor's F and so on) test null hypothesis of assumption being met against alternative that it is violated. So I can only reject null (conclude that assumption is violated) or say that I don't have enough evidence to do that. Typically, in later situation, I use parametric tests. This means that I use it when I do not actually know if assumptions are met. My conclusion: I should use nonparametric test anyway. My conclusion 2: I can use parametric test only when I have some "external" knowlegde about assumptions being met (like I somehow know exact distributions of my data). That's all. I'll be greatful for any suggestions if above makes sense. Edit: I know that parametric tests are more powerful when their assumptions are met. My concern is that we can never know that this is the case (unless we have "external" knowlegde). So, I think, using parametric tests is pointless since we don't know if we have data appropriate for them. Analogy that comes to my mind: Imagine two stain removers: Parametric Remover is perfect for cherry juice stains and Nonparametric Remover is OK, but not perferct, for all the stains. Since I can never confirm that my stain is cherry juice, I should always use Nonparameric Remover. | Can someone explain to me why would anyone choose a parametric over a nonparametric statistical method for hypothesis testing or regression analysis? In my mind, it's like going for rafting and choosing a non-water resistant watch, because you may not get it wet. Why not use the tool that works on every occasion? |
You can have a lambda calculus, the calculus of the real numbers or a logical calculus but on the other hand you could also have an algebra of sets, a Lie algebra, or a linear algebra. Is there any convention which dictates whether something is an algebra or a calculus? From my understanding, a calculus seems to give you information about objects you might encounter within a space, while an algebra gives you information about the interactions and structure within the space as a whole. Is this correct? | I sometimes see phrases like 'the relational algebra' or 'the lambda calculus'. What is the difference between an algebra and a calculus? |
I saw on SE that: $$\log(\sin x)=-\log(2)-\sum_{n=1}^{\infty}\frac{\cos(2nx)}{n} \phantom{a} (0<x<\pi)$$ This is an extremely useful identity, as it helps solve: $$\int_{0}^{\pi} \log(\sin(x)) dx$$ But how is it derived? From Taylor series, power series? How do I get this? Even if someone can start me off that would be great. | I saw the two identities $$ -\log(\sin(x))=\sum_{k=1}^\infty\frac{\cos(2kx)}{k}+\log(2) $$ and $$ -\log(\cos(x))=\sum_{k=1}^\infty(-1)^k\frac{\cos(2kx)}{k}+\log(2) $$ here: . How can one prove these two identities? |
I've implemented SSO with Salesforce using ADFS. Currently all users can login to Salesforce via SSO. I'd like to limit SSO to a subset of users based on user groups defined in AD. How can this be accomplished? | We've set up Single Sign on with SAML. Our IdP is OneLogin and using their link, we are able to connect. We now want to disable password login for some users in Salesforce. points me towards a "Use Single Sign On" or "Is Single Sign On Enabled" permission (depending on the age of the document) on the user profile, however I cannot find this permission. Does anyone know where to find it? |
Let a be a 2-dimentional list with each element being a set. For example, let a be a (3,3) list, I initialize as follows a = [set()] * 3 a = [a] * 3 I now want to assign a[1][1] with another set. I do a[1][1] = set([1,2,3]) But in doing this, not only a[1][1], but also a[0][1] and a[2][1] are assigned to this new set. It's so weird to me. How does this happen? How should I correct it? Thanks!! I set a to be a 2D list array because I want a to work like a = cell(3,3) as in Matlab. | I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3 The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]] Then I changed one of the innermost values: my_list[0][0] = 5 Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]] which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it? |
In my home i have installed solar pannel in 9 years ago. (20W pannel, 12V Solar Battry 35 A, 20Hr). Where my battry is almost dead but still it is working.we can use its 8w load to max 3hrs. But in day time its work good. So my question is, i have 12V 1A router, that i want to utilize it during power cut. But when i measure voltage its quite fluctuating from 12.3V to sometime 15V. Is it good idea to connect it directly without its adapter? And the interesting part is i am posting this, using this method. I am afraid to blow mg router at this time. I have no inverter, so i did cut the wire from adapter and connect it directly to router. Please expert explain what is the better option. Please help me to sove the provlem. Will it blow my router? How do i stabilize its voltage to 12v constantly. Can i use my 1250VA UPS for this solar battery? Can I replace Car battery to solar battery in my existing home solar pannel? | I have a Huawei internet router with 12 volt 2 ampere input power. I bought a solar panel 18V 10 watt with direct connection plug which I'm to use for the router but it seem to not working. Please I need solution on how to make this to device work because I'm using this where there is AC power at all typically sun base device is what is needed there, I thought of connecting the 12 volt adapter direct to the panel then to router but I don't just know how well it will work. |
I've got an M17X-R5 with the Intel 4800 cpu, Nvidia 3d graphics and it came with 5g wifi and a killer ethernet card. This is to replace my ageing M17x R1 which until recently worked perfectly with all I threw at it from Ubnutu 10.04 onwards. When I come to install Ubuntu 13.04 on the new Alienware, all appears well except it doesn't detect an internet connection to download the updates whist it installs. I've tried with a physical cable, via wifi and can only get it to detect a wireless connection if I plug in an old USB wifi adapter. After installing with the USB wifi plugged in, and all patches applied, it still refuses point blank to detect a network unless I use the USB adapter. I've tried installing Jockey and looking for additional drivers/hardware but none are found. I'm very comfortable with Unix/Linux/AIX etc, but have to admit that when it comes to drivers and Linux, I'm a novice. Any help would be appreciated. EDIT: In answer to PJ Singh's very pertinent question in the comment section, this is a snip from the lspci command taken at boot from a USB boot disk (Try Ubuntu option) without any external wifi dongles installed: 08:00.0 Ethernet Controller: Qualcomm Atheros Killer E2200 Gigiabit Ethernet Controller (rev 10) 0a:00.0 Network Controller: Broadcom Corporation Device 43b1 (rev 03) I should also note that when I said to begin with that it couldn't find any wifi networks to install the updates over, it actually couldn't find any wireless adapters. Edit: Added output from process here (nicer formatting) root@m17xr5-lnx:/usr/src/b43b1-6.30.223.95# lsmod | grep wl wl 4117081 0 lib80211 14352 2 wl,lib80211_crypt_tkip cfg80211 510937 3 wl,mac80211,rt2x00lib root@m17xr5-lnx:/usr/src/b43b1-6.30.223.95# cat /etc/modules wl root@m17xr5-lnx:/usr/src/b43b1-6.30.223.95# Edit: Resolved this today (September 29th 2013) by installing the latest Broadcomm drivers that are available with 13.10. No compilation required, just installed using the package manager and loh-and-behold, the wireless adapter came to life - didn't even need a reboot. | I bought a new computer, hoping to dual boot Win 8 and Ubuntu 13.04. I have successfully installed both OS, but in Ubuntu I have no connection to the internet, even though the ethernet cable is plugged in and internet works perfectly in Win 8. Already in the Ubuntu installer, it says that I have no internet connection. Things that might be of interest: I have this motherboard: MSI Z87-G45 Gaming () Internet did not work in Win 8 until I installed the networking drivers that came with the motherboard (Killer Ethernet something) I have tried different installation configurations, tried v. 13.04, 12.04 and 12.10, and tried installing on a separate hard drive. (the fact that the installer says "no internet connection" seems to indicate that the problem has nothing to do with the installation though.) I can't even reach my router at 192.168.0.1. The motherboard has no wireless capabilities. If I run the terminal command lspci I get the following output (among other things): 03:00.0 Ethernet controller: Qualcomm Atheros Killer E2200 Gigabit Ethernet Controller (rev 13) I have spent hours and hours googling, trying many different suggested methods and not quite finding someone who seems to be having the same problem. |
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