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I love using Hot Corners, but I regularly trigger them by mistake when performing other tasks, so I disabled them for a while and found I couldn’t live without this functionality. This got me to thinking - what if I could set a delay (0.5 secs) before the Hot Corners get triggered, or maybe set it so it’s triggered by a right-click action? I had a look at the Mission Control system preferences but didn’t see any way to do this instead of just accidentally moving the mouse.. Can I do this? Maybe a terminal command? Other suggestions welcome too. | I like the concept of hot corner actions but the trigger time for hot corner actions is too quick for me to make good use of them. I keep tripping my corner actions accidentally while reaching for objects in that general vicinity of the corner. Is it possible to extend the trigger time for hot corner actions? So I have to hover in the corner for at least a second or two before the hot corner action triggers? |
With the patch 2.0.1, you no longer can improve your MF with Paragon Level or Nephalem Valor buff. So is there a way to improve that stats without raising the difficulty level or playing in coop ? | What should I wear to maximize my Magic Find? What specific items are ideal for a Magic Find-optimized build? Does any one particular class have better class-specific items with increased Magic Find? |
I was thinking about the sentence "Could I Have This Kiss Forever" after listening the song "Could I Have This Kiss Forever" by Enrique Iglesias. And I'm confused is this sentence gives a same meaning like "Can I Have This Kiss Forever". If not what is the difference between "Could I Have This Kiss Forever" and "Can I Have This Kiss Forever"? Someone may think this question as a duplicate one, but I didn't find answer for my question by another question. Edit: At most questions about Could/Can they give some idea about Could/Can but not about the meaning difference of the above sentences. | Can you please explain this to me? Could you please explain this to me? I am unable to figure out which to use which situation. I did google, and some posts say they are both the same, even if the second one is more formal. Other posts say could is the past tense of can, but in the above example, I don't think could is used as past tense of can. What is correct way to use these words? |
I have a query related to a transformation of variables question; the images of which I have attached here. I have solved the question almost, but there seems to be a problem with the distribution that I have derived in the last line of the solution. I would greatly appreciate any kind of help. Thanks in advance. N.B.: In the question, $U$ should follow $N(\mu = 0, \sigma^2 = \frac{1}{4} = 0.25)$. | I am trying to prove the statement: If $X\sim\mathcal{N}(0,\sigma_1^2)$ and $Y\sim\mathcal{N}(0,\sigma_2^2)$ are independent random variables, then $\frac{XY}{\sqrt{X^2+Y^2}}$ is also a Normal random variable. For the special case $\sigma_1=\sigma_2=\sigma$ (say), we have the well-known result that $\frac{XY}{\sqrt{X^2+Y^2}}\sim\mathcal{N}\left(0,\frac{\sigma^2}{4}\right)$ whenever $X$ and $Y$ are independent $\mathcal{N}(0,\sigma^2)$ variables. In fact, it is more generally known that $\frac{XY}{\sqrt{X^2+Y^2}},\frac{X^2-Y^2}{2\sqrt{X^2+Y^2}}$ are independent $\mathcal{N}\left(0,\frac{\sigma^2}{4}\right)$ variables. A proof of the last result follows by using the transformation $(X,Y)\to(R,\Theta)\to(U,V)$ where $x=r\cos\theta,y=r\sin\theta$ and $u=\frac{r}{2}\sin(2\theta),v=\frac{r}{2}\cos(2\theta)$. Indeed, here $U=\frac{XY}{\sqrt{X^2+Y^2}}$ and $V=\frac{X^2-Y^2}{2\sqrt{X^2+Y^2}}$. I tried to imitate this proof for the problem at hand but it appears to get messy. If I haven't made any error, then for $(u,v)\in\mathbb{R}^2$ I end up with the joint density of $(U,V)$ as $$f_{U,V}(u,v)=\frac{2}{\sigma_1\sigma_2\pi}\exp\left[-\sqrt{u^2+v^2}\left(\frac{\sqrt{u^2+v^2}+v}{\sigma_1^2}+\frac{\sqrt{u^2+v^2}-v}{\sigma_2^2}\right)\right]$$ I have the multiplier $2$ above as the transformation is not one-to-one. So density of $U$ would be given by $\displaystyle \int_{\mathbb{R}}f_{U,V}(u,v)\,\mathrm{d}v$, which isn't readily evaluated. Now I am interested to know if there is a proof where I can only work with $U$ and don't have to consider some $V$ to show that $U$ is Normal. Finding the CDF of $U$ doesn't look so promising to me at the moment. I would also like to do the same for the case $\sigma_1=\sigma_2=\sigma$. That is, if $X$ and $Y$ are independent $\mathcal{N}(0,\sigma^2)$ variables then I wish to show that $Z=\frac{2XY}{\sqrt{X^2+Y^2}}\sim\mathcal{N}(0,\sigma^2)$ without using a change of variables. If somehow I can argue that $Z\stackrel{d}{=}X$, then I'm done. So two questions here, the general case and then the particular case. Related posts on Math.S.E: . . Edit. This problem is in fact due to L. Shepp as I found out in the exercises of An Introduction to Probability Theory and Its Applications (Vol. II) by Feller, alongwith a possible hint: Surely, $U=\frac{XY}{\sqrt{X^2+Y^2}}=\frac{1}{\sqrt{\frac{1}{X^2}+\frac{1}{Y^2}}}$ and I have the density of $\frac{1}{X^2}$ at hand. Let's see what I could do now. Apart from this, a little help with the integral above is also welcome. |
I am an Indian Citizen and Canadian PR holder. Want to book the flight from YYZ ( wow airline) have a route through Iceland (6.55 hours hold) to New-Delhi. Do I require Iceland Visa or Transit Visa? My outward flight is: Fri, Jan 11, 2019 Toronto (YYZ) 06:00PM New Delhi (DEL) 03:15 AM + 2 day Flight 1: | 5h 45m | WW214 | Operated by: WOW air Layover: 6h 55m | Reykjavik (KEF) Flight 2: | 10h 5m | WW322 | Operated by: WOW air And return flight is: Wed, Jan 30, 2019 New Delhi (DEL) 07:00 AMToronto (YYZ) 05:00 PM Flight 1: | 11h 50m | WW323 | Operated by: WOW air Layover: 2h 10m | Reykjavik (KEF) Flight 2: | 6h 30m | WW213 | Operated by: WOW air | I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows: Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland |
He knows a thing or two about being a doctor: study, study, study! Is this "being" the same as "becoming?" And why? | I am not good at English. And I used to say that I want to become a software developer. But Some people are using that I want to be a [something]. Which one is correct? And at what situations we should use which one? I read in many websites. Answers I have found so far are Be is abbreviation of become. Both are same. Be is representing continuous thing. Become represents future. I can't understand it because of people usage. Could anyone please further explain the difference between these two? |
Does anybody know what package shall I download or what to do to open .MDI files on Ubuntu 13.10? MDI: Microsoft Document Imaging Format | I have some insurance files that I need to be able to view, but they are in the MDI format I can't get them to work at all in Ubuntu. I've searched the entire forum and I've even installed Microsoft office 2003 & 2007 through Wine, but it still doesn't work correctly. The only solutions posted in the forum have suggested getting an MDI to pdf converter or installing MS office. I haven't gotten any of this to work. How can I view or convert MDI files? |
Hi I am trying to read a CSV File called test.csv in JAVA . Below is my code : import java.io.BufferedReader; import java.io.FileReader; public class InsertValuesIntoTestDb { @SuppressWarnings("rawtypes") public static void main(String[] args) throws Exception { String splitBy = ","; BufferedReader br = new BufferedReader(new FileReader("test.csv")); String line = br.readLine(); while(line!=null){ String[] b = line.split(splitBy); System.out.println(b[0]); } br.close(); } } This is my CSV File (test.csv): a,f,w,b,numinst,af,ub 1RW,800,64,22,1,48:2,true 1RW,800,16,39,1,48:2,true 1RW,800,640,330,1,48:2,true 1RW,800,40,124,1,48:2,true 1RW,800,32,104,1,48:2,true 1RW,800,8,104,1,48:2,true 1R1W,800,65536,39,1,96:96,true 1R1W,800,2048,39,1,96:96,true 1R1W,800,8192,39,1,48:48,true I am trying to print the first column in the csv ,but the output I get is only a in an infinite loop . Can anyone please help me fix this code to print the entire first column. Thanks. | Can anyone recommend a simple API that will allow me to use read a CSV input file, do some simple transformations, and then write it. A quick google has found which looks promising. I just wanted to check what others are using before I couple myself to this API. |
I have a 600EX-RT Canon flash, and am looking for a cheap Yongnuo flash to be used as a slave to the Canon. Do you know any Yongnuo than can reliably be used as a slave to my 600EXRT ? | My current flash setup is a standard shoe mount but I've been thinking about getting a remote. I've been drooling over the Speedlite 600EX-RT. It uses radio to control slaves, which is nice (longer distance, doesn't require line of sight, etc.). One thing I don't understand: do slaves also have to be 600EX-RTs or do other flash units use radio to communicate already? Can any (cheap?) flash slaves can be used with a Canon Speedlite 600EX-RT or do I need to buy the 600EX and a ST-E3-RT transmitter in order (or multiple 600EX-RTs) to have a radio-controlled remote flash setup? |
I've been reading SO discussion on how output going to a terminal is line buffered, and output to pipes or files etc is usually "block buffered". I am trying the following two pipelines on OSX, which aim to prepend a timestamp to the incoming lines: while [ 1 ] ; do echo $RANDOM && sleep .5 ; done | ~/bin/prepend_ts_python and while [ 1 ] ; do echo $RANDOM && sleep .5 ; done | ~/bin/prepend_ts_perl The Perl program is (and I don't know much about Perl): #!/usr/bin/perl while ( <> ) { print scalar(localtime()), " "; print; } The Python program (clearly not prepending a timestamp yet) is: #!/usr/bin/python import sys for line in sys.stdin: print("foo") The pipeline using the Perl version prints output immediately, as desired, whereas the Python one outputs intermittently. I was under the impression that any buffering that was going on was being determined by the while/echo loop, and for this reason people were recommending using the unbuffer command on the beginning of the pipeline. Does Perl have some way of flushing its STDIN? I didn't think it could reach "backwards" in the pipeline. Why are they different? | Is output buffering enabled by default in Python's interpreter for sys.stdout? If the answer is positive, what are all the ways to disable it? Suggestions so far: Use the -u command line switch Wrap sys.stdout in an object that flushes after every write Set PYTHONUNBUFFERED env var sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0) Is there any other way to set some global flag in sys/sys.stdout programmatically during execution? |
It seems that if I were to just express interest in a single subdiscipline (computer networking for example), and none of the networking professors are taking on students, I would not be considered based on any other merits my application may have. But if I were to express interest in several subdisciplines it may be difficult to create a structured statement of purpose. | I am wondering how many research interest should be included in a statement of purpose. Is it better to include just one core interest or to include up to three as in my case? |
When anonymous users go to /user, i would like to show the registration form instead of the login form, or just redirect to /user/register. I couldn't find anywhere how to do that... | Is it possible to redirect anonymous user to user/register page? How can I do that? |
How do I run a script as sudo at boot time? I need to run ethtool --offload <net> rx off to disable the annoying jme udp checksum error message. | I had a script that automatically enables my wifi without using networkmanager, but I don't know how to run the script as root while the system is booting. How do I make the script run automatically during boot? |
Let $n \in \mathbb{N}$, let $A \in \mathbb{R}^{n \times n}$ True or false? The linear system of equations for $Ax=b$ is uniquely solvable for every $b \in \mathbb{R}^{n}$ if and only if $\text{det(A)} \neq$ 0 I think the statement is true. Making $\text{det(A)} \neq 0$ should avoid us getting non-unique results such as $0=0$. Remebering this and knowing $\text{det(A)} \neq 0$ gives linearly independent vectors, we can only get unique solution. Edit: We don't know anything about $x$. If $x \neq 0$, then the statement will be true, right? Please correct me if I'm wrong / unclear, these tasks will be asked in my exam and I want pass it :) | I know there's a theorem in linear algebra that has a list of statements that are equivalent, as follows: $\det(A) \ne 0$ $Ax = 0$ has only the trivial solution $Ax = b$ is consistent for every matrix $b$ $Ax = b$ has exactly one solution for every $n \times 1$ matrix $b$ (and several other which I do not need for the question that I'd like to ask). So we've been learning about linear independence, span and bases, and I was wondering the following: Is statement 2 the same as saying a set of vectors are linearly independent? Is statement 3 the same as saying the set of vectors span a vector space? (Meaning that every single vector $b$ in the vector space can be made from some combination of $Ax$, where $A$ would represent that vectors and $x$ would be all of the scalar multiples of the vectors? Is statement 4 the same as saying the set of vectors is a basis? (since that one solution must be the trivial solution, it must be linearly independent, and since it is consistent for every $b$, it spans the vector space?) It seems pretty obvious that it's all related to each other, but I'm just wondering if they're all exactly the same. |
To have the best quality of figures in my document I'm using pdf images. But it seems that when the pdf images have very thin and/or transparent lines the final figure in the pdf gets messy, basically the lines get thicker and darker, unless the pdf is fully zoomed. This effect can be seen in the pictures below. Does anyone know the root cause of this and how to fix it? EDIT: And note the inconsistency in the thickness of the lines in the zoomed out version. While the zoomed in version all lines are the same thickness, as in the original image. Zoomed out figure: Zoomed in figure: | I use PCTEX 5.1. When I print from a DVI window my embedded graphics line plots are too thin and almost fade out. When I export the document to a PDF and print it the graphics line weights are much better; however, the PDF driver actually makes every second page, text and graphics, is a little lighter. The dvi driver doesn't do that. So first, can I get the dvi driver to increase the graphics line weights, and second is there a patch for the PCTEX PDF driver problem. |
In sentences like, "I'm dying to get to you and "I'm learning to live again" and "i was preparing to go for surgery when you called" what are "dying", "learning" and "preparing" functioning as? Are they verb(ing) or are they gerunds. | Progressive forms of verbs consist of the form to be + participle. At least that is what most English grammars say or they are imprecise and speak of the -ing form. My question is what follows after the forms of to be? I'm working in the garden. Is working here a present participle or rather a gerund? I asked myself this question long after I had left school, simply because one accepts what grammar books say without much reflection. But the longer I think about this problem, the more I tend to see it as a gerund. I stumbled upon this through a curious way of speaking in German dialects. Normally we don't use progressive forms in German, but some dialects make extensive use of forms such as Ich bin am Aufräumen - word-for-word translation: “I'm at tidying up”. Normally in English a preposition such as in "at tidying up" is omitted and it becomes: I'm tidying up. On another forum, a German language one, we noted the German dialects that made extensive use of such forms as beim/am Aufräumen—and we discovered that these forms are used extensively in areas along the River Rhine from Switzerland to the north, but also in the east of Germany and in the south. So it is reasonable to ask what form is used in English, participle or gerund? In German it is a gerund, a participle would be unusual. So it might be the same in English, but since participles and gerunds have the same form, it is really difficult to decide which form it is. I derive the progressive forms from a formula with "in the act of doing": I'm working in the garden means “I'm in the act of working in the garden.” When you omit "in the act of" you get the normal progressive form. I forgot to mention that the following archaic form also exist We were ahunting / went ahunting where one may assume that the prefix a- is a relic of a preposition. |
Take this code snippet for example: a = [] for x in range(2): a.append(lambda: print(x)) print(a[0](), a[1]()) The output is: 1 1 But I expected it to be 0 1 How do I fix this? | I want to create a list of lambda objects from a list of constants in Python; for instance: listOfNumbers = [1,2,3,4,5] square = lambda x: x * x listOfLambdas = [lambda: square(i) for i in listOfNumbers] This will create a list of lambda objects, however, when I run them: for f in listOfLambdas: print f(), I would expect that it would print 1 4 9 16 25 Instead, it prints: 25 25 25 25 25 It seems as though the lambdas have all been given the wrong parameter. Have I done something wrong, and is there a way to fix it? I'm in Python 2.4 I think. EDIT: a bit more of trying things and such came up with this: listOfLambdas = [] for num in listOfNumbers: action = lambda: square(num) listOfLambdas.append(action) print action() Prints the expected squares from 1 to 25, but then using the earlier print statement: for f in listOfLambdas: print f(), still gives me all 25s. How did the existing lambda objects change between those two print calls? Related question: |
Does there exists a nontrivial positive integer solution with $x\ne y,$ of $$x^4+y^4=2z^2.$$ | I would like to know any way of solving the diophantine equation $x^4+y^4=2z^2$. Or ideas that seem worth trying out. By solving I mean fining all solutions and proving there are no more. Keith Conrad showed how to reduce this equation to a different one which was solved by Fermat in his notes about Fermat descent, other than I have no ideas how to solve it. I tried to do descent on it directly but that seems completely impossible so I am interested in other techniques. Thanks very much. |
I have a question with regards to lagrange multiplers. The question is as follows: Find the points on the sphere x^2+y^2+z^2=4 that are closest to and farthest from the point (3,1,-1). Now, it is clear to me that the distance from any point to (3,1,-1) is simply using the R^3 metric, d=$$\sqrt((x-3)^2+(y-1)^2+(z+1)^2$$ and I can make the algebra easier by considering $$d^2$$. However, my question is as follows: How can I be sure that the maximum or minimum occurs when $$\nabla(d^2(x,y,z))=\lambda\nabla(g(x,y,z))$$ where $$g(x,y,z)=x^2+y^2+z^2$$? I would like an explanation in terms of tangent and normal spaces please? As i'm unable to find one. Furthermore, it is to my knowledge that the lagrange multiplier works when the contours of the function f(x,y) just touches the constraint g(x,y)=c. However, is it possible to have contours of f(x,y) where the contours increase and decrease and wouldn't then the lagrange multiplier not work? | I know that the Lagrange multiplier method helps us evaluate critical points of $f$ on the closed boundary of the restriction. In other words we solve:$$\nabla f=\lambda \nabla g$$ But why does this method actually work? Can someone please give me an explanation. Thank you! |
I want to run a bash script in a directory /media/aliakbar/New Volume(internal drive)/further/path/to/file . The problem is: with chmod +x the file's permission is not changed (proof: I couldn't execute script from terminal): -rw------- 1 aliakbar aliakbar 561 Jun 8 14:05 buildscript_0.10.0.sh I moved the file to /home/<user>/Downloads/, did chmod +x which worked, and moved file back to /media/aliakbar/New Volume(internal drive)/further/path/to/file, replaced non-executable file but still with ls -l there's no change!? NOTE: I'm on Ubuntu LTS 14.04 (dualboot) with df -T run in file directory returning: /dev/sda3 fuseblk 277228568 168883892 108344676 61% /media/aliakbar/New Volume New Volume is on an internal drive unfortunately I don't know how it's mounted, I have only an empty /etc/fstab.d/ folder What am I doing wrong? | sorry fresh user. I installed about 9 days ago and had issues with Unity disappearing which took 5 days of headaches to fix. It never did fix, I reinstalled. I set up Plex (media server) and while the server is running and can be accessed by external network devices, I can't add files. Plex says this is because of permissions. I have gone up and down the forums here and at Plex to get an answer. It seems everyone says chmod -R 755 /media/My\ Book/Videos will change permissions to allow the folder "Videos" on my external USB 2.0 NTFS 3TB Western Digital drive (which is mounted and accessible through the file manager) as well as every sub-directory and file contained therein to be accessible to user "Plex". I have used file manager and as soon as you click to change permissions it changes right back. When I chmod with -c it tells me every file is changed (usually 600) to 755 as I commanded it to do. I did ls -l to verify and there is no change. (I also used ls -l to make sure I knew who the owner was and it is me (mvl1014). ls -al gives me the same info.) I swear to god I tried to sudo it and after smashing my head against this keyboard for basically the entirety of my day, I tried it as root. I was scared shi-less but couldn't come up with anything else. sudo su to root and then chmod -R -c /media/My\ Book/Videos Same result. -c told me every single file was changed and a check in Unity or in terminal confirmed not a darn thing changed. Now it seems to me that even if that isn't the thing stopping Plex from working there is still a problem with this command not going through. 12.04LTS -- on gen 1 i7 (2.7 GHz I believe) with 6 GB ram I've attempted to attach a screenshot but I'm told I need 10 reps to do so, which means I'm copy/pasting too. Please excuse my obfuscation, but Lorem Ipsum seemed unnecessary. And I tried multiple ways to format this but it looks perfect every way and messed up each time in the preview below. (Ugh, I'm a mess.) $ chmod -R -c 755 /media/My\ Book/Videos ..... ..... ..... mode of `/media/My Book/Videos/xxxx/xxxx/xxxx.mkv' changed from 0600 (rw-------) to 0755 (rwxr-xr-x) ls -al shows: mvl1014@FX6800:/media/My Book/Videos$ ls -al total 88 drwx------ 1 mvl1014 mvl1014 0 Aug 28 15:17 . drwx------ 1 mvl1014 mvl1014 20480 Sep 3 14:29 .. drwx------ 1 mvl1014 mvl1014 8192 Aug 28 15:18 xxxx drwx------ 1 mvl1014 mvl1014 49152 Aug 16 14:02 xxxx drwx------ 1 mvl1014 mvl1014 8192 Aug 27 21:36 xxxx drwx------ 1 mvl1014 mvl1014 4096 Jul 23 19:09 xxxx I apologize if this has been asked. I looked through this place plus at all the suggested "Similar Questions". The closet thing I got to an answer , but running the provided code with my own UID didn't work either. |
I remember a time when anonymous users could post questions without an account on Stack Overflow. , this is no longer possible. I don't mind the removal. I DO, however, find it interesting that it was built and then removed. What was the rationale? Are there any blog posts talking about it? Are there any stories from the trenches that lead to the decision? Why did Stack Overflow drop anonymous content? I ask because I'm faced with a similar situation and tested wisdom is interesting. (Again, I don't want this to be a feature debate, but rather a historical recounting). | I know SO's policy is "you don't have to register to ask questions," but there are so many new members and so many hit-and-runs... The majority of the questions I see now are coming from new users (i.e., it's their first question). Although unregistered users should still be able to ask questions, I think we should encourage users to create an account. Here is a couple of ways we could do that: Explicitly encourage people to get an account: there's currently nothing telling people to do that. Maybe tell people something like "Get an account, it's easy!" and maybe show some of the perks of having an account (and having rep). Maybe give a few bonus points for registering; and have that enable a basic privilege. It could be taken from one of the , for example. Of course getting people to register is just half of the battle. I don't know what the stats are on this, but I think there's a number of users who create multiple accounts anyways. We could curb that by: Having smart(er)? duplicate account detection systems, alerting someone who is about to create a new account and possibly has an account already. Give them a message like "Hey, it looks like you already have account, are you sure you want to create a new one?" Create a new privilege (10k? 20k?) that gives users tools to detect possible duplicate accounts, eg: "List users with the same e-mail," "List users with the same IP addresses," etc. (without revealing said emails and IPs). Then the 10k/20k can look at other stuff (e.g.: posts) and refer the new user to a moderator for a possible merge. |
Can we just say that if between 2 points in some given circuit, there's no load, then the potential at those 2 points are same? | I understand all the concepts of what voltage is using all the analogies but some things related to the drop of voltage across a circuit confuses me. If I had a short circuit and attached a voltmeter I would get a potential difference reading of 0 volts. How is current then going through the wire if it is 'X' volts at any point in the wire? Let's say I have a DC 9V battery with a load in the middle. I read somewhere (probably mistaken here) that the voltage drop in this situation must be 9V or rather, that the sum of load resistances must be equal to voltage of the source. I mean, there is a variable amount of resistance to each load so at the base of the load I might have 9V and at the end of the load I might have 5V with a 4V potential difference. |
I recently had one question put on "Hold" on Stack Overflow and was really sad, shocked and confused. It turns out that I modified my question, another user also improved it a lot and it was reopened. But I'm still amazed and disturbed by the fact that I cannot ask question like "What is the best...". This type of question has some negatives: Create emotional reactions Attracts spams Attracts non objective answers, sometimes by creators of products/software Could lead to inappropriate exchange/words Generate lots of unnecessary information It is subjective But these kinds of questions also have their positives: It create debate where lots of useful information came out Brings new information that could lead to change some minds / a new vision to readers In most case, those questions lead to a solution that will save a lot more time than any other kind of question In most case, those questions lead to a solution that will save a lot more of money than any other kind of question (usually related to products) Brings creator reaction that would bring additional useful information on the product, reason of certain design decision, ... In summary: Considering the negatives and the positives, and also considering that Stack Overflow has a really good system for rewarding/penalizing users, I think that the acceptance of this type of questions would be a lot more beneficial for users than anything else. It is only because Stack Overflow has this rewarding system that it could support those type of questions easily whithout too much drawbacks. Also, Stack Overflow has the best reputation and is recognized as the best question/answer system now for programmers (it is subjective I know, but don't be blind, be honest and admit it), then I think that it returns to Stack Exchange to offer that type of question for the benefits of everyone. If Stack Overflow does not support this type of question, what can we do? Where can we go to have lots and good reactions to this type of questions? Who will do it? | I needed to find a good Perl module to do HTML parsing. The good thing about Perl is the CPAN (module library) with gazillions of modules to do everything, the bad thing is that it's hard to find the right module. So I though, let's ask Stack Overflow: “What is a good Modern Perl way to parse HTML documents?” I quickly got one great answer and several good comments. I would have gotten at least one more good answer, but then the question was put on hold because it's “subjective”, and it couldn't be added anymore. In spite of protests, it was then closed and later deleted. I've got the answers that I needed, but now other people will be deprived of this useful information. Is it really so important to stick to the rules that this question had to be removed? Yes, it's subjective. By definition. I want people's opinions about what module I should use, after all. The question got 8 plus-votes and 2 minus-votes, so others thought it was useful too. The URL was , but I think it only works when logged in as me. Do I need to start looking for another site to ask such questions? If so, too bad, I really liked Stack Overflow until now. |
I upgraded from 14.04 which had Gnome DE. My Grub is black in colour since then. I am hoping to reinstall Grub to match with Unity I have now. I do not have any other DE s for now. Does reinstalling Grub give me stock 16.04 ? If yes, give me the commands, please. Update : Reinstalling Grub has no effect on Gnome-ish black elements while booting, sadly. Update 1 : I am not looking to change colour. I tried reinstalling Grub to remove Gnome-ish elements and get dotted boot screen by Ubuntu during start up and shutdown. | I use the latest version of Grub Customizer (3.0.2) and Ubuntu 12.04. On appearance settings I changed the background image and the font, but once I reboot the system they don't appear; there's always the default Ubuntu background image and the font seems a bit changed but not as expected. I tried to resize and crop the image as described here: but it doesn't work in any case. On /etc/default/grub: # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT="0" #GRUB_HIDDEN_TIMEOUT="0" GRUB_HIDDEN_TIMEOUT_QUIET="true" GRUB_TIMEOUT="10" GRUB_DISTRIBUTOR="`lsb_release -i -s 2> /dev/null || echo Debian`" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL="console" # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE="640x480x15" # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID="true" # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" export GRUB_MENU_PICTURE="/home/attilio/Immagini/grub/1366.jpg" export GRUB_COLOR_NORMAL="white/black" export GRUB_COLOR_HIGHLIGHT="light-cyan/black" GRUB_FONT="/boot/grub/unicode.pf2" Thank you very much in advance. |
I have a list of integer a=[1,2,3,4,5,6,7,8,9] and i must create a string with the integers separated by spaces and every five number i must add a '\n' string='1 2 3 4 5\n6 7 8 9\n\n' I have tried with a join like that: string=' '.join(a) but i don't know how to add '\n' with a condition. | I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive. I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators. I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though. Related question: |
I'm trying to install ulsy in order to use its blitz symbols for proofs by contradiction. I downloaded the metafont source from CTAN: I then unzipped it in texmf/tex/latex I ran latex ulsy.ins and latex ulsy.dtx and produced the .sty file. At this point, the compiler was able to find the .sty file but produced an error message saying that it could not find the .tfm file. Somme other answers suggested that this problem could be resolved by installing the following: texlive-latex-recommended texlive-latex-extra texlive-fonts-recommended However, this did not work for me. I then tried moving the .tfm file to texmf/fonts/tfm/public/ulsy and the .mf file to texmf/fonts/source/ulsy Now when I try to use the symbols in math mode, I just get arbitrary greek letters, but my understanding is that ulsy's symbols are supposed to be used in text mode anyway. Unfortunately, I am getting the following error message when I try to use ulsy's symbols in text mode: !pdfTeX error: pdflatex (file ulsy10): Font ulsy10 at 600 not found ==> Fatal error occurred, no output PDF file produced! kpathsea: Running mktexpk --mfmode / --bdpi 600 --mag 1+0/600 --dpi 600 ulsy10 mktexpk: don't know how to create bitmap font for ulsy10. mktexpk: perhaps ulsy10 is missing from the map file. kpathsea: Appending font creation commands to missfont.log. pandoc: Error producing PDF from TeX source Error: pandoc document conversion failed with error 43 Execution halted Can anyone point me in the right direction or guide me through the manual installation? | Frequently there are questions about, how to manually install a font, what very often means “Type1 font”. So I thought, we should write a general answer about the several aspects to regard. Beside the usual approach for it seems, that for fonts further steps are necessary. What are these steps? Or better: How to manually install fonts and their associated support files in TeX distributions? |
True or false: There exists a continuous function $f: \Bbb R \to \Bbb R$ such that $f(\Bbb Q) \subseteq {\Bbb R}\setminus {\Bbb Q}$ and $f({\Bbb R}\setminus {\Bbb Q}) \subseteq {\Bbb Q}$. My attempt: I was trying to use the sequential definition of continuity. Consider $a \in \Bbb R$ then we have a seqn ${x_n}$ of rational numbers converging to $a$ and we have a seqn ${y_n}$ of irrational numbers converging to $a$. Then what will be $f(a)$? I was thinking that in one way $f(a) \in \Bbb Q$ and on the other way $ f(a) \in {\Bbb R}\setminus {\Bbb Q}$ . But I am wrong $\{f(x_n)\} \subseteq {\Bbb R}\setminus {\Bbb Q}$ and $\{f(y_n)\} \subseteq {\Bbb Q}$ still $f(a)$ can be anywhere. Is there any way to fix my attempt or any other possible idea? | Is there a way to prove the following result using connectedness? Result: Let $J=\mathbb{R} \setminus \mathbb{Q}$ denote the set of irrational numbers. There is no continuous map $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f(\mathbb{Q}) \subseteq J$ and $f(J) \subseteq \mathbb{Q}$. |
If a rock is thrown at someone's head, or a car drives against a wall, or a meteor hits a planet, is the physical damage done to the object proportional to the projectile's momentum, or to its kinetic energy? (assume that the target object is at rest in the reference frame). I'm sure that it depends on all kinds of factors, but roughly, does it depend linearly on the projectile's speed (as momentum does), or quadratically (as kinetic energy does). | Let's assume we have 2 bullets. The first bullet has $450$ $J$ of KE and $3$ $kg.m/s$ of momentum, while the second bullet has $250$ $J$ of KE and $5$ $kg.m/s$. Now if they are both shot at ballistic gelatin, which one is expected to cause more damage if both are stopped by the gelatin? By damage here I mean more penetration, bigger cavity, heat and any other deformation of the gelatin. In other words, if the velocity of a projectile is doubled, will the amount of damage it causes when it collides with an object double or quadruple? |
American tourist here. I understand the 180 day scheme, 90 days in (non-consecutive), 90 days out (consecutive). Here’s the question: I enter the Schengen area on Jan 1st and leave the Schengen area on Jan 31st (30 days) leaving me 60 Schengen days unused. Can I wait outside the Schengen for an extended amount of time, say 5 or 6 months, and then arrive in the Schengen area with my 60 days still usable? | I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory: My situation: I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation? |
this is my first time asking on stackoverflow, and I have a trouble when programming with python 2.7. Here I have a calculation: 1350/2.7 The exact answer must be 500, but python give the answer 499.99999999999994 I know about the fact that some numbers cannot be represented exactly in binary, causing error on floating calculation. So can anybody give me an advice? How to deal exactly with it? | Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004 Why do these inaccuracies happen? |
I am just wondering if there would be any loss of speed or efficiency if you did something like this: int i = 0; while(i < 100) { int var = 4; i++; } which declares int var one hundred times. It seems to me like there would be, but I'm not sure. would it be more practical/faster to do this instead: int i = 0; int var; while(i < 100) { var = 4; i++; } or are they the same, speedwise and efficiency-wise? | I have always wondered if, in general, declaring a throw-away variable before a loop, as opposed to repeatedly inside the loop, makes any (performance) difference? A (quite pointless) example in Java: a) declaration before loop: double intermediateResult; for(int i=0; i < 1000; i++){ intermediateResult = i; System.out.println(intermediateResult); } b) declaration (repeatedly) inside loop: for(int i=0; i < 1000; i++){ double intermediateResult = i; System.out.println(intermediateResult); } Which one is better, a or b? I suspect that repeated variable declaration (example b) creates more overhead in theory, but that compilers are smart enough so that it doesn't matter. Example b has the advantage of being more compact and limiting the scope of the variable to where it is used. Still, I tend to code according example a. Edit: I am especially interested in the Java case. |
Especially when you are a new user your vote doesn't count (yet). I found myself voting on questions at the beginning but quickly lost motivation for it because it always went something like this: Post has X votes I vote Post has quickly X+1 votes Gets reverted to X votes in the next instant Now there's at least a notification that your vote gets saved. But when it is already saved, why not show the vote all the time in the first place? In some places I have enough points that my votes do count but I still don't use it because I'm used to it not making any difference. If you change it to show the vote from the start, users are maybe more interactive with the voting system. Because if you look at the views of question and the upvotes of the answers, only a fraction of them actually casts a vote. | Users below 15 reputation can't effectively vote. It says: Votes cast by those with less than 15 reputation are recorded, but do not change the publicly displayed post score Does it mean that they will take effect after I reach 15 reputation or because they were cast before, they're recorded but ignored? |
I'm having an issue trying to set up the default posts post type to use the permalink structure of /news/%postname%/ - I've tried editing the permalinks but it throws out my other custom post types. I've currently got two other custom post types; 'careers' and 'case-studies' which use /careers/%postname% and /case-studies/%postname% When adding "/news/" into the permalink settings it adds that to the custom post types as well, which I don't want. To help explain, it makes the two custom post types change to /news/careers/%postname% etc. Is there a way I can change the slug or permalink structure of the default "posts" post type or another way around this issue please? I've tried various solutions and had a good look around for similar issues but they aren't quite the same. | I would like to set a permalink structure with a prefix that will appear just on the posts. The prefix should only be displayed for the posts and not for the permalinks of categories or tags. I set the permalink structure as /post/%post_id% and the post URL is example.com/post/12345. But the prefix added also to the categories and tags and it become example.com/post/category/news instead of example.com/category/news. How I can do it? |
Consider: If only it could snow in the town, my city would look amazing! First, I would like to know is it "If only" or "only if"? which is more idiomatic? What about: only it could snow in the town, my city ... As another example: only if I had that car, I would be in Hawaii now if only I had that car, .... Second I would like to know do I need "the" before "town"? because I've seen there is no "the" in phrases like "in town", is it a universal rule for any case? | What is the differences between "if only" and "only if" ? What is the use of each in the sentences? Are there any specific rules for their uses? "I could get more work done if only there weren't so much noise." "We will manufacture these handbags only if we can obtain the right leather." |
I obtained two groups of data from my experiment and calculated the binomial distribution for each group, trying to see if they are significantly different from each other. However, the z sore I got was way smaller than -4, which was a little bit odd to me. Here is how I did my calculation: The control group: # of trails n1=34; # of successes k1=2, success rate p1=2/34=5.9% The experimental group: # of trails n2=25; # of successes k2=2, success rate p2=2/25=8.0% average p=6.8% standard error=0.0044 test statistic z=(5.9%-8%)/standard error=-4.77 It's a two-tailed test. I couldn't find a p-value corresponding to the z score I got (-4.77) on the table. Does that mean my p-value was just really small or I made mistakes here? | I have three groups of data, each with a binomial distribution (i.e. each group has elements that are either success or failure). I do not have a predicted probability of success, but instead can only rely on the success rate of each as an approximation for the true success rate. I have only found this , which is close but does not seem to exactly deal with the this scenario. To simplify down the test, let's just say that I have 2 groups (3 can be extended from this base case). Group 1 trials: $n_1$ = 2455 Group 2 trials: $n_2$ = 2730 Group 1 success: $k_1$ = 1556 Group 2 success: $k_2$ = 1671 I don't have an expected success probability, only what I know from the samples. So my implied success rate for the two groups is: Group 1 success rate: $p_1$ = 1556/2455 = 63.4% Group 2 success rate: $p_2$ = 1671/2730 = 61.2% The success rate of each of the sample is fairly close. However my sample sizes are also quite large. If I check the CDF of the binomial distribution to see how different it is from the first (where I'm assuming the first is the null test) I get a very small probability that the second could be achieved. In Excel: 1-BINOM.DIST(1556,2455,61.2%,TRUE) = 0.012 However, this does not take into account any variance of the first result, it just assumes the first result is the test probability. Is there a better way to test if these two samples of data are actually statistically different from one another? |
Could it be possible that all of the unexplained phenomena (like uncertainty) in our 4D world might be originated from a higher dimension universe? If so, then of course we'll never observe the actual phenomena since we only live in a lower dimension world. For people who live in higher dimension universe, all that is uncertain for us, is deterministic for them. | I've often heard the argument that having 3 spatial dimensions is very special. Such arguments are invariably based on certain assumptions that do not appear to be justifiable at all, at least to me. There is a on Wikipedia. For example, a common argument for why >3 dimensions is too many is that the gravitational law cannot result in stable orbital motion. A common argument for <3 dimensions being too few is that one cannot have a gastrointestinal tract, or more generally, a hole that doesn't split an organism into two. Am I being overly skeptical in thinking that while the force of gravity may not be able to hold objects in stable orbits, there most certainly exist sets of physical laws in higher dimensions which result in formation of stable structures at all scales? It may be utterly different to our universe, but who said a 4D universe must be the same as ours with one extra dimension? Similarly, isn't it very easy to conceive of a 2D universe in which organisms can feed despite not having any holes, or not falling apart despite having them? For example, being held together by attractive forces, or allowing certain fundamental objects of a universe to interpenetrate, and thus enter a region of the body in which they become utilized. Or, conceive of a universe so incomprehensibly different to ours that feeding is unnecessary, and self-aware structures form through completely different processes. While I realise that this is sort of a metaphysical question, is 3+1 dimensions really widely acknowledged to be particularly privileged by respected physicists? |
The code below compiles and works as expected. On line 11, when I change std::istringstream iss(temp) to std::istringstream iss() , it stops working. An error occurs on line 18, iss.str(temp): expression must have class type but it has type "std::istringstream (*)()" Why would a change to the constructor make a difference? I checked the , it shouldn't make a difference, but I must be missing something. Any thoughts? #include <vector> #include <iostream> #include <string> #include <sstream> int main() { int n, m; std::string temp; std::vector<int> ranked, player; std::istringstream iss(); // Get the Input std::getline(std::cin, temp); n = std::stoi(temp); std::getline(std::cin, temp); iss.str(temp); while(!iss.eof()) { std::getline(iss, temp, ' '); ranked.push_back(std::stoi(temp)); } return 0; } | Is there any good reason that an empty set of round brackets (parentheses) isn't valid for calling the default constructor in C++? MyObject object; // ok - default ctor MyObject object(blah); // ok MyObject object(); // error I seem to type "()" automatically everytime. Is there a good reason this isn't allowed? |
I stuck in the login loop ubuntu 18.10 and after I enter ctrl+alt+f3 I can not log in to my user account 'jake' but I can log in to 'root' then I can not see any xauthority in the file system. what should I do with root to fix the login loop | My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back. I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M |
I am writing in TexStudio and it builds PdfLatex if I don't include the printbibliography command. But when I include it, it shows printbibliography as an unrecognized command and I don't get Bibliography page into my pdf output. I have also tried compiling the .bib file (as it was working few days ago) with just one citation, before I actually use the mentioned citation into my .tex file but it does not compile (see the image of an error). I think as I can't compile .bib file, I'm not getting bibliography into the pdf output. Any suggestion? \usepackage[ backend=biber, style=numeric, sortlocale=de_DE, natbib=true, url=true, doi=true, eprint=false ] {biblatex} \addbibresource{literatur.bib} % Biblatex Kompatibilität \usepackage{csquotes} \begin{document} \include{inhalt/01-Introduction} \include{inhalt/02-CHP_systems} \listoftables \printbibliography \begin{appendix} \include{Appendix} \end{appendix} \end{document} | Could anybody give me some help on this problem I've come over? \documentclass{article} \usepackage{natbib} \begin{document} \bibliographystyle{ormsv080} \bibliography{MST_TBS} \printbibliography \end{document} when compiling, I got the error: ! undefined control sequence 1.13 \printbibliography |
How to change the label of title field bydefault its showing Title I need to change it to "Custom-title" of node edit form programatically. I tried function mymodule_form_alter(&$form, FormStateInterface $form_state, $form_id) { if ($form_id =="slices_slices_cta_5_edit_form") { kint($form[title][widget][0]['#title']); dpm($form[title][widget][0]['#title']->jsonSerialize()); $form[title][widget][0]['#title']->jsonSerialize()==t("Custom-title"); //dpm($form[title][widget][0]['#title']->getArguments()); } I just want to change [string] property of class TranslatableMarkup's object of above screen shot. How to access the value of a Drupal\Core\StringTranslation\TranslatableMarkup object within a form I want to do something like below example: $form[title][widget][0]['#title']->string = t('New-title'); Not working above solution. | The property 'string' is protected as I can see here but I need to change word "- Any -" in my exposed filter form to my string "All terms"? I cannot do this cause I do not know how to use this class and how to change output. This hook says: cannot get value of protected property. function MYtheme_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) { if ( ( $form['#attributes']['class'][0] == 'views-exposed-form' ) && ( $form['#info']['filter-field_color_target_id']['operator'] == 'field_color_target_id_op' ) ) { dpm($form['color']['#options']['All']->string); //$form['color']['#options']['All']->string = t('All terms'); } } |
What is the fundamental difference(s) between Ehrenfest dynamics and Born-Oppenheimer MD? Also, in what situation(s) or case(s) one is preferred than the other one? | I am new to the world of Molecular Dynamics, and am curious to know exactly what is considered to be an ab initio Molecular Dynamics (AIMD) method, and how do they work? The seminal work by Roberto Car and Michele Parrinello, titled "" was published 35 years ago! I have recently come across the following "types" of MD methods while reading some research papers: Born-Oppenheimer Molecular Dynamics Car-Parinello Molecular Dynamics 2nd generation CPMD Approximate Car-Parrinello-like Langevin Born-Oppenheimer Molecular Dynamics Many-body Molecular Dynamics If I am missing methods, which I am sure I am, please feel free to add them through an answer! Also, it would be appreciated if one method is explained per answer, and is summarized in 2-3 paragraphs. |
BACKGROUND I'm an electrical engineering graduate student. I submitted and abstract to a conference and it was accepted. This happened about 3-4 months ago. Since then, I have mainly focused on other unrelated work. CURRENT The paper deadline approached and I submitted the paper. About 10 days later, I realized there were a few errors. These errors include plots which were left in the paper that I intended to replace with updated accurate plots. So I submitted the paper with errors. QUESTIONS What do you recommend I do? Will this negatively effect my reputation with the conference? How big of a problem is this? My advisor was not happy with me for barely submitting this on time - so this mistake further complicates my problems. Thanks | I am an engineering MS student (maybe going for PhD). I submitted a conference paper on some research I was working on last week. Before I submitted a conference paper, I regenerated all the plots (for a better consistent format). I realized today that I used an inaccurate, older code to regenerate a few plots in one section. This means that some of the plots are based on a code that had a theoretical error. Not good. Questions: What do you recommend I do? Is it ok to send the accurate plots a week later? Have I damaged my reputation with this forum? Are there ethical issues here - technically I sent innacurate plots but it was a small technical mistake? |
int main(void) { char *temp = "ABCDE"; temp[2] = 'X'; printf("%s", temp); return 0; } In gdb I could see that temp[2] = 'X' is causing the crash. But why? Could some answer please? | The following code receives seg fault on line 2: char *str = "string"; str[0] = 'z'; // could be also written as *str = 'z' printf("%s\n", str); While this works perfectly well: char str[] = "string"; str[0] = 'z'; printf("%s\n", str); Tested with MSVC and GCC. |
I'm having trouble inputting random generated passwords into some scripts. I generate the password, and paste it between "". But sometimes it contains characters that sends the whole thing crashing down, like " # or whatever. EDIT: I have been pointed to Quoting for a solution There are several options for Quoting ( using \ , " " and ' ' ) but each require checking the string for special characters, like single quotes in a single quote block. Is there a way to really paste a string without needing to check it or is doing that check always necessary when your random string can contain the ' character at least. | I want to enter the following folder in the terminal: Milano, Torino (Jan)-Compressed How should I write the command cd to enter this directory? Spaces and several other special characters like \, *, ), ( and ? cause problems when I try to use them in the command line or scripts, e.g.: $ cd space dir bash: cd: space: No such file or directory $ cat space file cat: space: No such file or directory cat: file: No such file or directory $ cat ( bash: syntax error near unexpected token `newline' $ echo content >\ > ^C $ ls ? ( ) * ? \ How do I enter file or directory names that contain special characters in the terminal in general? |
I want to build a shell script that accepts multiple optional parameters. However, I'm somehow stuck when getting the parameters. I want the script to be called in multiple ways scriptname test -gm [email protected] This would create a folder test, init a git and add the remote with the given URL scriptname test -gm [email protected] -ig This would do the same as above but also install grunt/a gruntfile for the user scriptname test -ig This would create a folder test, and install grunt without doing anything with git However, it seems like only my -gm parameter is used in the script while [[ $# > 2 ]] do key="$2" case $key in -gm|--gitremote) GITREMOTE="$3" shift ;; -ig|--installgrunt) echo 'test' shift ;; *) # unknown option ;; esac shift done Test never gets outputted. Does it have something to do with key=$2" ? I don't really know how to have optional multiple parameters | Say, I have a script that gets called with this line: ./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile or this one: ./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile What's the accepted way of parsing this such that in each case (or some combination of the two) $v, $f, and $d will all be set to true and $outFile will be equal to /fizz/someOtherFile? |
Someone stole my MacBook. How can I find it if it’s offline. I have its serial number if it helps. Please if someone knows, tell me. I have really important stuff on it and I can’t get it back. Thank you so much. | I have used "Find my Mac" to find our Macbook Pro. It was pretty accurate and was able to place the computer within 10 feet of its actual location. I started thinking about how it actually works, since the MBP doesn't have a GPS. How does "Find my Mac" work? |
Is there an elementary explanation of why the row-rank of a matrix equals its column-rank (without using adjoint maps, resp. lots of technical computations)? What is the geometric intuition behind this? | I am auditing a Linear Algebra class, and today we were taught about the rank of a matrix. The definition was given from the row point of view: "The rank of a matrix A is the number of non-zero rows in the reduced row-echelon form of A". The lecturer then explained that if the matrix $A$ has size $m \times n$, then $rank(A) \leq m$ and $rank(A) \leq n$. The way I had been taught about rank was that it was the smallest of the number of rows bringing new information the number of columns bringing new information. I don't see how that would change if we transposed the matrix, so I said in the lecture: "then the rank of a matrix is the same of its transpose, right?" And the lecturer said: "oh, not so fast! Hang on, I have to think about it". As the class has about 100 students and the lecturer was just substituting for the "normal" lecturer, he was probably a bit nervous, so he just went on with the lecture. I have tested "my theory" with one matrix and it works, but even if I tried with 100 matrices and it worked, I wouldn't have proven that it always works because there might be a case where it doesn't. So my question is first whether I am right, that is, whether the rank of a matrix is the same as the rank of its transpose, and second, if that is true, how can I prove it? Thanks :) |
The bug : Click the upper line of the legend in other to make it go away, chart is zoomed not only down but also left. Notice the red line disappearing from the zoomed chart. Notice yaxis going crazy. Click the upper line of the legend again in order to make it come back, chart tries to go back to the initial zoom, maybe accomplishes that, I don't know, but lines alignment have changed. Notice yaxis not going completely normal. Either the first chart or the third chart are wrong data. This is Opera 62.0.3331.119. Can reproduce using Firefox Quantum 68.0.2 and Chromium 47.0.2503.0. This is macOS 10.14.6. How this is different from (even likely related to, root cause might be the same but manifestations are different). If I double click lines in legend, this happens. Dis-adjustment seem to be larger than in my initial report. Notice yaxis acts weirdly in a very similar way to my initial report. Double click on the legend line corresponding to the blue line when it is enabled. Double click on the legend line corresponding to the green line when it is enabled. As a notable difference, what I report causes a JS console red message. Contrary wise, not (that one doesn't log anything at all when being reproduced): highcharts.js?v=61b1d1bf4167:12 Error: <path> attribute d: Expected moveto path command ('M' or 'm'), "0". Corresponding stack: r @ highcharts.js?v=61b1d1bf4167:12 attr @ highcharts.js?v=61b1d1bf4167:297 c.<computed> @ highcharts.js?v=61b1d1bf4167:258 X.h @ jquery.min.js:3 X @ jquery.min.js:3 n.Animation.n.extend.tweeners.* @ jquery.min.js:4 nb @ jquery.min.js:4 map @ jquery.min.js:2 qb @ jquery.min.js:4 g @ jquery.min.js:4 dequeue @ jquery.min.js:3 (anonymous) @ jquery.min.js:3 each @ jquery.min.js:2 each @ jquery.min.js:2 queue @ jquery.min.js:3 animate @ jquery.min.js:4 ec @ highcharts.js?v=61b1d1bf4167:257 animate @ highcharts.js?v=61b1d1bf4167:291 render @ highcharts.js?v=61b1d1bf4167:72 (anonymous) @ highcharts.js?v=61b1d1bf4167:61 o @ highcharts.js?v=61b1d1bf4167:254 m @ highcharts.js?v=61b1d1bf4167:61 redraw @ highcharts.js?v=61b1d1bf4167:101 (anonymous) @ highcharts.js?v=61b1d1bf4167:157 o @ highcharts.js?v=61b1d1bf4167:254 h @ highcharts.js?v=61b1d1bf4167:155 setVisible @ highcharts.js?v=61b1d1bf4167:561 a @ highcharts.js?v=61b1d1bf4167:190 Z @ highcharts.js?v=61b1d1bf4167:257 (anonymous) @ highcharts.js?v=61b1d1bf4167:190 | On the , when you either double-click on the legend or click quickly1, the graph lines seem sketched out by this, and move to the left, away from the action (also, they don't always all move the same distance, the one you're clicking on seems to become misaligned from the rest): I can make this happen on: Chrome 58, Windows (also in an incognito tab, also confirmed on OS X) Firefox 53, Windows IE 11, Windows Chrome Whatever, Android Also, while the graph lines' trust can be earned back by clicking slowly (whereupon they will return to calmly grazing on the legend's grassy field), as Laurel noticed in , some of the X axis labels are far more timid, and e.g. 2013 and earlier simply run away entirely. 1 Say "click quickly" five times fast. I could barely type it. |
I have a number with an exponent and an uncertainty that I want to display in an S-column in a table. When I just put it in, the spacing is terrible, and if I tell the column how much space to reserve for the number, the brackets around the value and the uncertainty disappear, making the expression faulty. It looks something like this: \documentclass{article} \usepackage[separate-uncertainty]{siunitx} \begin{document} \begin{tabular}{| S | S[table-format=1.2(2)e-1] |} {not reserved} & {reserved} \\ 1,72(53)e-3 & 1,72(53)e-3 \\ \end{tabular} \end{document} How can I aovoid this but still have a nicely spaced table? | I would like to format the space reserved for a number shown in a table with separated uncertainty. It seems that when I use the table-format option the brackets around the mantissa disappear. This is illustrated in the example below: \documentclass{article} \usepackage{siunitx} \begin{document} \begin{table} \begin{tabular}{ S[separate-uncertainty = true] S[table-format=1.1(1)e1, separate-uncertainty = true] } {Header} & {Header}\\ 1.0(2)e2 & 1.0(2)e2\\ \end{tabular} \end{table} \end{document} I have also tried to use the bracket-numbers and multi-part-units = brackets without solving this issue. Is there any workaround to center the number and keep the brackets like in the first column of the example? |
I'm thinking about buying a new car. I'm thinking of buying a new car. Do we use "about" or ‘of" in sentences above? | Could someone help me to understand when I should use think of and when think about in sentences? What is the difference between using one or the other? |
Can someone explain why i got this strange "artifact". I'm following a tutorial. | While rendering a mesh with smooth shading on, I get a dark region/shadow on certain faces. The effect is more evident when smooth shading is applied to a mesh containing ngons, with the ngons turning black when rendered. The blackening effect is visible in the viewport too. How can I solve this problem? |
Subject says it all. I'm sure I've seen this somewhere, so if someone can link me to a wiki page or post that explains, that works for me. | A little bird told me that if $2^n+1$ is prime, then $n$ is a power of $2$. I tend not to trust talking birds, so I'm trying to verify that statement independently. Suppose $n$ is not a power of $2$. Then $n = a \cdot 2^m$ for some $a$ not a power of $2$ and some integer $m$. This gives $2^n+1 = 2^{a \cdot 2^m}+1$. Now I suspect there's a way to factor that, but I don't see how. Can someone give me a hint? |
I have a Class RequestHelper where I store methods for http-Requests to initiate Requests from different Activities. E.g. there is this one: class RequestHelper { static void loginUser(String email, String password, final Context activityContext) { // do request stuff } } Is there any difference if I put a public in front of it like in the following example or is it just nonsense to do so? class RequestHelper { public static void loginUser(String email, String password, final Context activityContext) { // do request stuff } } Both versions do work as planned, so is there any difference at all? | In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance? |
Situation: unconfigured network interface eth1. As root, I give command dhclient eth1, and get an IP. Now I want to change this IP from client side, force DHCP client to get a new address. Answers of only have command to release and re-aquire the lease, but I get the same IP every time, so it does not answer the question. I am looking for a generic Linux solution, not dependent on this exact environment, but just for reference, this is my current environment: OS: Ubuntu 14.04 running as a VirtualBox quest DHCP server: VirtualBox host-only network Also I am aware of following solutions which would work with above: use the VM to set a new MAC address, so it would probably get a new IP too, or simply manually configure another IP for the host-only network. But I am specifically asking how to force a new DHCP IP from client side without rebooting, if such a thing is possible with DHCP at all. Alternatively, if someone can confirm that DHCP does not support client wanting an IP address change, preferably with a reference, that would be valid answer, too. | How to request a specific IP address from DHCP server? This question also touches the topic of DHCP address reservation in a router. Background: My home routers DHCP table only allows to create an IP address reservation of an assigned IP. It does not let me edit the table and manually assign the device an arbitrary IP for the next renew. |
I know how to unpack a tar.gz file but am clueless when it comes to the next procedure as I opened file install and it opened up in gedit as a installation script, now the question is how do I run it??? What is the next step??? Thanks in advance for your help... Vektron | I have downloaded tar.gz files. But I don't know how to install it. How do I install this kind of file? |
Here is an example of what I am trying to do: #!/bin/bash Update=$1 if [$Update == Value] then NewValue= $Update vi %s/Value/$NewValue/g > Updatedfile fi exit 0 Is there a way to utilize vi commands within a script? My thoughts are that some type of piping would do this? | Replacing strings in files based on certain search criteria is a very common task. How can I replace string foo with bar in all files in the current directory? do the same recursively for sub directories? replace only if the file name matches another string? replace only if the string is found in a certain context? replace if the string is on a certain line number? replace multiple strings with the same replacement replace multiple strings with different replacements |
I have a problem in my code in android studio, I created it to say "Hello" when the person "abc" writes but that didn't work . can u plz help me. here is my codes final Button butt=(Button)findViewById(R.id.butt); butt.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { final EditText frag =(EditText)findViewById(R.id.frag); final TextView hello=(TextView)findViewById(R.id.hello); String verb =frag.getText().toString(); if (verb=="abc"){ hello.setText("Hello"); | I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? |
I am currently running 20.04 (development branch). Will this upgrade automatically to 20.04 LTS when it's released or is there some action I'll have to take to move to the LTS version? | I installed an Ubuntu alpha or beta and have been keeping it up to date. So, Should I presume that my system has automatically updated to the next alpha or beta, and will be running the official release when it's finished? |
my script: #!/bin/sh PATH=$PATH:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin if pgrep -x "firefox" >/dev/null then return else firefox & fi my crontab: * * * * * /home/jesuscrew77/sc.sh It runs manually but doesn't start with crontab. what is wrong? | I want to write a crontab that opens Firefox every minute (just to test it, I know it doesn't make any sense). My problem is that even though crontab is active nothing happens. This is how my crontab looks like: SHELL=/bin/bash PATH=~/bin:/usr/bin:bin * * * * * export DISPLAY=:0.0 xhost localuser /usr/bin/firefox Any idea why it isn't working? |
How do I upgrade my iPhone 4 to run iOS 9.0? Can this be done without a computer? I need it to download Facebook, YouTube and WhatsApp. | I have an iPhone 4 and I need to upgrade from 7.1.2 to iOS 8 or 9. I would like to ask how I can get iOS 8. |
I recently updated to 16.04 (64 bit) and I'd really love to be able to make my laptop hibernate on closing the lid. I'm able to successfully hibernate by typing sudo pm-hibernate into terminal but I tend to forget to do this when tossing my laptop in my bag and then I pull out a dead computer. I've followed the directions here: with no luck. Are there any other options I can try to get my computer to automatically hibernate? EDIT: following the instructions at the above link, I've used dconf Editor to set hibernate on lid closed and also set /etc/systemd/logind.conf to hibernate on lid switch | I would like to use the hybrid suspend method instead of suspend when closing the lid or selecting "Suspend" from the menu. I can imagine to change the pm-suspend script to do so automatically, but there might be a more maintainable / easier way. |
I got the idea that expansion of the universe is not to somewhere, it is just getting stretched of spacetime since a point of singularity. And I know that universe was calculated as flat (which means sum of angles of a triangle is exactly π ignoring local instrinsic curvatures caused by celestial masses) with a very small error rate. But still universe is possible to be hyperbolical or elliptical. If it is elliptical, when you travel on a straight route, you will eventually arrive at your starting point (we assume expansion of the universe is frozen). So, can we say that in that travel I am actually circumnavigating on the surface of a higher dimensional sphere and that means spacetime has an extrinsic curvature beside its intrinsic curvature. | General relativity tells us that the universe is bent by gravity, but this curvature is intrinsic to the universe (the universe bends, but not in a fourth spatial dimension, the universe having only three bent spatial dimensions). How could we know the difference between the intrinsic curvature of a 3D spatial universe, and a the extrinsic curvature of a 3D shape in a 4D universe? Obviously, there is a similar question about our curved 4D spacetime inside a 5D spacetime. |
Ok so I saw at work a script which is on OpenVMS using the DCL scripting language that they have a way to do a catch all for warnings or errors etc... There is a page about it here. basically its ON warning THEN GOTO sendfailemail or something like that. I was wondering without using a bunch of if statements is there a way to do such a thing in bash? I am looking for something that can do a trap not just based on ERR but return code. What is nice about vms is that you can do on warning which on vms is exit status 0 vs error which is exit status 2. So I know I can do trap ... ERR but I wanted something that could trap exit status 1 or 2 specifically. | What is your favorite method to handle errors in Bash? The best example of handling errors I have found on the web was written by William Shotts, Jr at . He suggests using the following function for error handling in Bash: #!/bin/bash # A slicker error handling routine # I put a variable in my scripts named PROGNAME which # holds the name of the program being run. You can get this # value from the first item on the command line ($0). # Reference: This was copied from <http://www.linuxcommand.org/wss0150.php> PROGNAME=$(basename $0) function error_exit { # ---------------------------------------------------------------- # Function for exit due to fatal program error # Accepts 1 argument: # string containing descriptive error message # ---------------------------------------------------------------- echo "${PROGNAME}: ${1:-"Unknown Error"}" 1>&2 exit 1 } # Example call of the error_exit function. Note the inclusion # of the LINENO environment variable. It contains the current # line number. echo "Example of error with line number and message" error_exit "$LINENO: An error has occurred." Do you have a better error handling routine that you use in Bash scripts? |
I have walk through many questions and answers here which are not cleared.and getting Error: Invalid child of messaging:emailTemplate. Only messaging components are allowed as children of messaging:emailTemplate. <apex:repeat value="{!attachments}" var="attachment"> <messaging:attachment renderas="{!attachments[0].ContentType}" filename="{!attachments[0].Name}"> </messaging:attachment> </apex:repeat> ERROR like: Error: Invalid child of messaging:emailTemplate. Only messaging components are allowed as children of messaging:emailTemplate. | I'm creating a UI that feeds into an email template via visualforce. One of the features I want to add is the user should be able to click checkboxes and add attachments to an email template. When the user clicks a button to get to the constructed email template, those attachments are added. From the UI part, I have the attachment ID's, but i don't know how to get those multiple attachments added to the email template. Also, you can't do <apex:repeat> on <messaging:attachment> A couple of constraints - 1- The attachments could be any type - .gif, .pdf, .csv 2- I'd like the attachments to have their actual names 3- what ever the file type is, i'd like it to stay that way 4- I'd prefer not to do a batch apex There is a related q here: |
Show by a counter-example that if U+W =U+X for subspaces U,W,X of V, then W need not be equal to X. | Let $V$ be a vector space and $U,W$ and $Z$ subspaces of $V$. Does $V = W \oplus Z$ and $V = U \oplus Z$ necessarily means that $W = U$? Thanks! |
Why are data that are one and a half times the interquartile range (1.5IQR) or more, measured from the first and third quartiles, classed as outliers. Why 1.5? | I was looking at the outlier detection formula which uses the IQR and I wonder why it should be multiplied by 1.5? Can the constant be increased i.e 3 or 6 to be more "acid" if so under what criteria? |
I can't see why this has to be the case. I've computed the vertices, given the constraint inequalities and equations. So, now all that's left is to plug in these vertices into the function to find my maximal value. Can someone explain why I was essentially done with the problem (finding the max) as soon as I found the vertices? | I'm in high-school and I'm told that the maximum/minimum of a linear programming occurs at the vertex.For more info see the chapter . For convinience I'm putting relevant excerpt here: Now, we see that every point in the feasible region satisfies all the constraints, and since there are infinitely many points, it is not evident how we should go about finding a point that gives a maximum value of the objective function. To handle this situation, we use the following theorems which are fundamental in solving linear programming problems. The proofs of these theorems are beyond the scope of the book. Theorem 1 Let R be the feasible region (convex polygon) for a linear programming problem and let Z = ax + by be the objective function. When Z has an optimal value (maximum or minimum), where the variables x and y are subject to constraints described by linear inequalities, this optimal value must occur at a corner point (vertex) of the feasible region. Theorem 2 Let R be the feasible region for a linear programming problem, and let Z = ax + by be the objective function. If R is bounded, then the objective function Z has both a maximum and a minimum value on R and each of these occurs at a corner point (vertex) of R I searched wikipedia to get under Optimal vertices (and rays) of polyhedra: "..then the optimum value is always attained on ... This principle underlies the simplex algorithm for solving linear programs.." But I couldn't understand it. Can someone explain?It might be helful to add that I have studied basic Calculus. |
only have dev/sd1 with full disk space how can I resize it to get some unallocated space for installing another os? | 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? |
there is a discrepancy between the viewport hair ( how I intend it to be) and the render in Cycles What's the reason for this difference | I made the eyelashes for my mesh and though it will be fine as it looks in the picture Particle Edit Object mode but after I render the eyelashes look very messy like this What I am doing wrong? Here my Hair settings Thanks in advance |
Let $p$ be a prime number. Prove that for any field $K$ and any $a \in K$, the polynomial $x^p−a$ is either irreducible, or has a root. it doesn't seem hard, but i have no idea. any hint is welcomed! thank you | Let $K$ be an arbitrary field, $p$ a prime and $a\in K$. Show $f=x^p-a$ is either irreducible in $K[x]$ or has a root in $K$. My strategy was to split this up into a case for each characteristic. The characteristic $p$ case is easy. Assume $f$ is reducible $=gh$ both smaller degree $g$ irreducible, with $\alpha$ a root of $g$. Then in $K(\alpha)[x]$, $f=(x-\alpha)^p$. So $g=(x-\alpha)^k$, and all the other factors of $f$ are of the same form. Hence they are all equal to the $minpoly(\alpha)$ and the degree of $minpoly(\alpha)|p$ so it is $1$ or $p$ and we are done. The characteristic $0$ case and characteristic $q\ne p$ I get stuck on. If $K$ contains a primitive $p$th root of unity $\zeta$, then over $K(\alpha)$, $f$ splits into linear factors. So the degree of the field extension for any root of $f$ is the same, so the degree of such a root is either $1$ or $p$. If $K$ does not have a primitive $p$th root of unity, then simply adjoin one. We know $[K(\zeta):K]|p-1$ and by the previous step either $f$ is irreducible over $K(\zeta)$ or splits into linear factors. If it is irreducible we are done, if not we have it splits into linear factors of the form $x-\zeta^ia^{1/p}$, but I am unsure what to do from here. The characteristic $q$ case seems similar to the characteristic $0$ case but again I am stuck trying to finish the proof. Some googling has lead me to believe that this problem is generally approached using the field norm and if an accessible online reference exists I would love to see it, but I feel that in the context I have seen it should be entirely possible that this is done without needing the norm. As I have not seen the field norm before, I would like to know if there is a possible way to prove this without using it and hopefully that follows in the same vein my attempt at a proof did. |
If a helicopter flies linearly in the upward direction from a point A on the earth stays in the air at the same position for a long time and then linearly comes down , will it land at the same point A or at a different point since the earth is rotating ? | Suppose we have a helicopter that is able to stay stationary in flight for extended periods of time. If such a helicopter stayed at point A in the sky for 12 hours straight, would it reach the other side of the globe? |
Draw a 5x5 square. In 16 of 25 squares draw diagonals in such a way that no diagonal ends touch. How can I do this? | I have and I have to fill 16 little squares with a diagonal Rules You cannot place more than 1 diagonal in each square The diagonals cannot touch each other (example bellow) But what I seek here is a mathematical solution for this puzzle, I don't even know where to start looking for information. Can someone explain how do I solve this puzzle using equations? |
I installed ubuntu on a Windows Vista laptop last year, didn't use it much and now am trying to update to newer version and run other updates that it lists, but it asks for my password and I have no idea what it is. I do not have any files to save as I just used it for internet access so would like to just completely start over, install latest version and not setup passwords, any guidance for someone that is really just savy enough to install a printer driver. | 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 have a directed multigraph with no self-loops: What's the most efficient way to mark nodes 1, 2 and 3 as being members of a cycle? My first thought would be to Perform a depth-first search starting from an arbitrary node Push all nodes I've seen in a given branch into a "seen" array. Also, mark each node as "checked". For each new node, check if any of its children are in the seen array If it is, mark each node in the array between the seen node and its previous occurrence as seen While traveling down the DFS, make sure to skip any children who have been seen Repeat 1-5 with the next node that hasn't been marked as "checked" yet (since I may have disconnected regions of the graph) This seems like it might work, but wonder if it's the most efficient way, give that I've got to maintain an array of "seen" nodes, and, since this has to be called recursively, I think I may be doing a lot of array modification (e.g. at one point in my algorithm I'll have [0,1,2,3,1] and another point I'll have [0,1,2,3,4], for the graph above, so it's not just "build once"). I also have to go through the list an additional time at the start to removed the "checked" mark that may have been left over from a previous test. | What is the most efficient algorithm for detecting all cycles within a directed graph? I have a directed graph representing a schedule of jobs that need to be executed, a job being a node and a dependency being an edge. I need to detect the error case of a cycle within this graph leading to cyclic dependencies. |
Suppose two sets of 2 elements each, $X = \{x_1, x_2\}$ and $Y = \{y_1, y_2\}$ are uniformly and independently chosen from the set of positive integers ${1, . . . , r}$. What is the probability that the sets $X$ and $Y$ are disjoint? | Suppose two sets of $2$ elements, $\{X_1, X_2\}$ and $\{Y_1, Y_2\}$ are uniformly and independently chosen from the set of two element subsets of the integers $\{1, 2, \dots, r\}$, where $r \geq 1$. What is the probability that the two sets are disjoint? What is the probability that the two sets are the same? What is the expected size of the intersection of the two sets? I've tried to attempt these questions, but I'm completely wrong. It would be nice if you guys can help me out. Thanks |
I have 2 machine setup of rhel7 , one is in terminal mode and the other is in grahical mode , when I run 'who' command on both the machines why do I get 'tty' in 2nd column output for the machine in terminal mode and 'pts' for machine in graphical mode | Possible Duplicate: I always see pts and tty when I use the who command but I never understand how they are different? Can somebody please explain me this? |
I wanted to install Clementine and noticed 2 of them in the Ubuntu Software Center, as shown in the image: Is there a difference between the two? Are they both different versions? Or is something more shady going on? | When I search for Chromium in Ubuntu Software on Ubuntu 16.04, There are 2 options. Which one should I select? The same can be observed with , , etc. |
How can I calculate the duration my solar battery will last after charging to full? I want to know how to calculate the battery back up time. | How do I calculate how long a battery operated product will run? Here's what I've got: 2 AA, 1.5V, 2700mAH batteries Voltage Regulator with a Iq of 25 uA Voltage Regulator Eff = 80% Active Current = 50mA Sleep Current = 1uA Duty Cycle = 99.9% (only active 0.1% of the time) Active Voltage is 3.3V I've gone the current route and got an answer. I went the power route and got a TOTALLY different answer (days vs years different). How do you do this? |
I'm dual-booting Windows 8.1 and Ubuntu 14.04. While installing, I gave Ubuntu 50GB of my disk space but now I'm finding that it is small for me. So is there any way I can decrease my Windows C: drive and increase the Ubuntu partition without affecting dual-boot. I've read posts saying how to do it but I'm afraid that I'll mess up my dual-boot and break my bootloader. My GParted: I want to take 50GB from from C: Drive(/dev/sda4) and give it to the Ubuntu drive(/dev/sda9). Please guide me through it. UPDATE : I removed 50GB from my C: drive but I am now unable to add it to my /home directory. I can only make that 50GB into a new partition which is not what I need. Is there any way how I can add that 50GB to /dev/sda9. The /dev/sda10 [50GB Volume] is the one I want to delete and add to /dev/sda9. | 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? |
We know Hogsmeade is the only all-wizard town in Britain. So wouldn't some students' family live there? Not only is it a nice all-wizard place to live, but you would see your kids during Hogsmeade weekends. So why do we never hear about relatives living there? | Hogsmeade has a lot of individuals who live there, and it has the distinction of being the only non-muggle community in the UK. Are there any students at Hogwarts who live there during the summer? I ask because explicitly says that students must ride the train or not go to the school at all, which seems silly for someone who already lives at the destination. Many pure-blood families were outraged at the idea of their children using Muggle transport, which they claimed was unsafe, insanitary and demeaning; however, as the Ministry decreed that students either rode the train or did not attend school, the objections were swiftly silenced. |
My wife is a Chinese national residing in Belgium. We would like to do the following itinerary: Belgium --> Hong Kong (<7 days) --> Mainland China (e.g. Chengdu) --> Belgium I assume my wife does not need a permit to go to Hong Kong. I assume she can return to Belgium from mainland China (no need to go back from Hong Kong)? Can anyone confirm my assumptions ? | I and my girlfriend (a mainland Chinese citizen) are planning to visit Hong Kong from Malaysia (where we both have MSC working visas), and will also be returning to Malaysia. I have been surprised at all of the restrictions placed on mainland Chinese citizens; it seems that there is a lot of bureaucracy required before a mainland Chinese citizen can enter Hong Kong. I am trying to find out if there is some way that she can enter Hong Kong for 3-4 days with me (a British citizen) without having to go through the hassle of trying to get a visa. After a little while reading, I found : Chinese passport holders who are in transit through Hong Kong from another country, region or territory may be granted a stay of 7 days without the prior need to obtain an entry permit, with the condition of possession of valid Chinese passport and confirmed onward air tickets for the overseas journey. If Chinese passport holders will go for mainland China or Macau via Hong Kong, onward air tickets are not compulsory. It seems that this could be used to allow her visaless entry to Hong Kong, as we only plan to go for 3-4 days. So here are my questions based on that 7-day exemption clause: Does the "onward air tickets" stipulation apply when flying from and returning to Malaysia, or would it only apply if we were flying on to another country entirely? If "onwards air tickets" may not apply in that situation, does flying back to Malaysia via Macao or mainland China permit her to enter without a visa? Does simply entering mainland China without flying (for example, using the Hong Kong–Shenzhen Western Corridor to drive there) also entitle her to this entry? I have contacted the Chinese embassy in Malaysia about these questions, but they advised me that they do not know the answer to them (which I find a little surprising). |
How does principal component analysis (PCA) model data of admittedly higher dimensionality with just a few principal components? | In today's pattern recognition class my professor talked about PCA, eigenvectors and eigenvalues. I understood the mathematics of it. If I'm asked to find eigenvalues etc. I'll do it correctly like a machine. But I didn't understand it. I didn't get the purpose of it. I didn't get the feel of it. I strongly believe in the following quote: You do not really understand something unless you can explain it to your grandmother. -- Albert Einstein Well, I can't explain these concepts to a layman or grandma. Why PCA, eigenvectors & eigenvalues? What was the need for these concepts? How would you explain these to a layman? |
Recently in some LaTeX documentation I noticed that there is a special LaTeX command for the symbol meaning "corresponds to", which is similar to an equal sign with a hat on top. \hat{=} or \widehat{=} both do not give satisfying results (my personal view). Unfortunately, I cannot remember which documentation it was! Does anyone know the command or the documentation where to find it? The symbol I am looking for: PS: I have already tried but it didn't produce anything useful! Also, browsing wasn't successful. | I want to use unicode character 2259 "estimates" in my document, but cannot find it in the symbols-a4 list or via . It looks exactly like this: ≙ The closest I get is \triangleq: ≜, but it has a different meaning. |
I'm trying to complete a simple program using multiple methods to compute the grade of a test, yet my method will not return any letters. The IDE says that my method must return a result of type String. public static String getGrade1(int num1) { if (num1 <= 100 && num1 >= 90) { String a = "A"; return a; } else if (num1 < 90 && num1 >= 80) { String b = "B"; return b; }else if (num1 < 80 && num1 >= 70) { String c = "C"; return c; }else if (num1 < 70 && num1 >= 60) { String d = "D"; return d; }else if (num1 < 60) { String f = "F"; return f; } } | I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? |
I recently made Ubuntu 12.0.4 bootable through my flashdrive. I've done this before, and have had no problems on previous flashdrives; the only problem I ran into then was I ran out of space, and now I reformatted my flashdrive to give me more space. The program I am trying to install is Wine 1.7, and the instructions given aren't working for me this time. When I try and install it through terminal, I get this message every time: Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: wine1.7 : Depends: wine1.7-amd64 (= 1:1.7.12-0ubuntu1) but it is not going to be installed Depends: wine1.7-i386 (= 1:1.7.12-0ubuntu1) Recommends: fonts-droid but it is not installable Recommends: ttf-mscorefonts-installer but it is not installable Recommends: fonts-horai-umefont but it is not installable Recommends: winetricks but it is not going to be installed E: Unable to correct problems, you have held broken packages. If anyone knows what this means I'd appreciate it. | Occasionally, when I'm installing stuff, I get an error like the following: Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages. How can I resolve this? |
Which are the most secure password hash algorithm(s) in PHP? Speed is irrelevant because I'm iterating the hash over a fixed time (rather than a fixed number of iterations). What I'm interested in is the mathematical strength. My intuition tells me it's whirlpool, being the largest and slowest of the bunch. That or SHA-512. Which is recommended by experts? Are there any other algorithms which provide more than 512 bit hashes? | It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection. This question, suggests that hashing multiple times may be a good idea, whereas suggests using salt. I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters. The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?) Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer? In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism. Related questions that don't quite cover my question: |
I'm doing some test, and I created a local repos to version some files. I would like to restore all my files to their state at a previous commit. Is it possible ? I know that git checkout file restore a file to the current commit state. However I'm not sure if git checkout * do the same for all file, and even more here I'm not sure if it's possible to restore from more than just the latest commit. | I have made some changes to a file which has been committed a few times as part of a group of files, but now want to reset/revert the changes on it back to a previous version. I have done a git log along with a git diff to find the revision I need, but just have no idea how to get the file back to its former state in the past. |
I am new so bear with me. But I am getting a NullPointerException somewhere in here. Any ideas? Thanks! private void loadInstructors() { // get all account numbers from database try { //myResultSet = myStatement.executeQuery( "SELECT DISTINCT lastname FROM InstEval" ); myResultSet = myStatement.executeQuery( "SELECT DISTINCT TEAMNAME FROM APP.TEAMEVAL" ); // add account numbers to accountNumberJComboBox while ( myResultSet.next() ) { //instructorComboBox.addItem( myResultSet.getString( "lastname" ) ); TeamsComboBox.addItem( myResultSet.getString( "TEAMNAME" ) ); } myResultSet.close(); // close myResultSet } // end try catch ( SQLException exception ) { exception.printStackTrace(); } } | What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely? |
Given: $\theta>0$, $X_1,...,X_n$ i.i.d. RV with $p_{\theta}(x) = \frac{1}{\theta}, \text{where } 0 \leq x \leq \theta$ and $p_{\theta}(x)=0, \text{else.}$ In the given exercise the MLE solution $L_X(\sigma)$ is $L_X(\sigma)=\frac{1}{\sigma^n}1_{\{0\leq X_{(0)} \leq X_{(n)} \leq \sigma \}}$ with the order statistic, which I unterstand. But then they claim $\hat\theta = X_{(n)}$ if $\theta\geq X_{(n)}$ and zero else, without a lot of explanation. Can you explain me this solution? I see that $\frac{1}{\sigma^n}$ is strictly decreasing for $\sigma>0$. But it seems to me that we cannot conclude without knowing if the maximum of the RV is $X_{(n)} < 1$ or $X_{(n)}\geq1$. | There is a classic problem: Suppose that $X_1,\ldots,X_n$ form an i.i.d. sample from a uniform distribution on the interval $(0,\theta)$, where $\theta>0$ is unknown. I would like to find the MLE of $\theta$. The pdf of each observation will have the form: $$ f(x\mid\theta) = \begin{cases} 1/\theta\quad&\text{for }\, 0\leq x\leq \theta\\ 0 &\text{otherwise}. \end{cases} $$ The likelihood function therefore has the form: $$ L(\theta) = \begin{cases} 1/\theta^n \quad&\text{for }\; 0\leq x_i \leq \theta\;\; \text{for all }i,\\ 0 &\text{otherwise}. \end{cases} $$ The general solution is usually that the MLE of theta must be a value of $\theta$ for which $\theta \geq x_i$ and which maximizes $1/\theta^n$ among all such values. The reasoning is that since $1/\theta^n$ is a decreasing function of $\theta$, the estimate will be the smallest possible value of $\theta$ such that $\theta\geq x_i$. Therefore, the mle of $\theta$, $\hat{\theta}$, is $\max(X_1,\ldots,X_n)$. Here, I do not understand why we cannot just differentiate the likelihood function with respect to theta and then set it equal to $0$? Thanks! |
I was just out and about looking for posts to help me secure the timelord hat and I found If you notice at the first of the question it says Dear All. If however, you click edit and look at the text the Dear All has vanished. This feels like a remove salutation bug, or the reverse of that, edit being right, and the post being wrong. EDIT: @gunr2171 has since edited the post and the Dear All goes away. | I edit a lot of posts every day. I often run across posts with 'Hi' and 'Thanks' on the top and the bottom of the post respectively. I also run across things like: --User Should these items be removed during the editing of the post by an editor? |
When I start Octave, on the command window I see this: However, after I run some commands, I can see they are in history and they do execute. I can see the text if I copy-paste it somewhere. How can I make the command window text visible? | I've installed Octave 4.2.0 on Ubuntu 16.04: wget ftp://ftp.gnu.org/gnu/octave/octave-4.2.0.tar.gz tar xf octave-4.2.0.tar.gz rm octave-4.2.0.tar.gz cd octave-4.2.0/ ./configure make -j8 sudo make install However there is a graphical bug in my Octave terminal: The rows in terminal are stupidly small to see the present code. How can I get rid of this bug? |
On Chrome's settings page, chrome://settings, when I go to Search Engine -> Manage search engines chrome://settings/searchEngines and edit stuff in "Other search engines", where are those settings stored? They're synced to my account, but can I download them and import them from another Chrome user/share them with other people? | I have created some search entries in Google Chrome using 'Edit search engines'. How can I share some of these entries with my colleagues? |
This is my .sql file, it's saved as "Split.sql" and is located in C:\ INSERT Employee (Name) values ('Roland Eric Real') SELECT * FROM Employee GO select Name, -- instead of spaces you can use any delimiter that you have like a comma -- We replace the delimiter with dot, which is used by the function PARSENAME PARSENAME( REPLACE(Name, ' ','.') ,3) as LastName, PARSENAME( REPLACE(Name, ' ','.') ,2) as FirstName, PARSENAME( REPLACE(Name, ' ','.') ,1) as MiddleName from Employee GO -- If you need to alter the table then -- Alter the table and add new columns ALTER TABLE Employee ADD LastName varchar(50), FirstName varchar(50), MiddleName varchar(50) GO -- Moving the data from FullName to the new columns UPDATE Employee SET LastName = PARSENAME( REPLACE(Name, ' ','.') ,3), FirstName = PARSENAME( REPLACE(Name, ' ','.') ,2), MiddleName = PARSENAME( REPLACE(Name, ' ','.') ,1) GO SELECT * FROM Employee GO -- Now we can drop the old column ALTER TABLE Employee DROP COLUMN Name GO -- Reclaim space by rebuilt the table ALTER TABLE Employee REBUILD GO SELECT * FROM Employee GO I am using windows form in visual studio c#. Basically, when I press a button in windows form, I want it to run that code in sql. Any help would be appreciated, thank you. ^_^ | I need to execute a large set of SQL statements (creating a bunch of tables, views and stored procedures) from within a C# program. These statements need to be separated by GO statements, but SqlCommand.ExecuteNonQuery() does not like GO statements. My solution, which I suppose I'll post for reference, was to split the SQL string on GO lines, and execute each batch separately. Is there an easier/better way? |
My uncle is traveling from Dubai to Amsterdam and then to Quito. He is citizen of Ecuador and Pakistan, currently in Pakistan. He will arrive at 5 AM in Dubai from Lahore and leave Dubai at 11:55 PM on the same day. I want to know how long he can stay in Dubai airport without visa. He will travel by KLM airlines from Dubai to Amsterdam and then from Amsterdam to Quito. Does he need a visa in Dubai? | Do I need a transit visa for a layover via airports in the UAE, such as Dubai International Airport or Abu Dhabi International Airport? If so, what are the requirements for such a visa? Can I get the transit visa on arrival? |
I've got a string s, and I'm trying to map each letter in s to the number of times it appears in s, using the Stream API. For example, giraffe -> {1, 1, 1, 1, 2, 2, 1}. The code I've tried using is: String s = "giraffe"; int[] occurences = s.chars().map(c -> count(s, c)).toArray(); public int count(String text, char ch) { return (int) text.chars().filter(c -> c == ch).count(); } but I get incompatible types: possible lossy conversion from int to char on the line that starts with int[] occurences = ... I've tried some different variations but nothing has worked. Any ideas? Thanks | I have the string a.b.c.d I want to count the occurrences of '.' in an idiomatic way, preferably a one-liner. (Previously I had expressed this constraint as "without a loop", in case you're wondering why everyone's trying to answer without using a loop). |
I want to know if it's possible to write out the line \def\TEMP{ to a file, and then later write } to close the brace-pair in the written file? Essentially I'd like to do; \documentclass{article} \newwrite\TEMP \immediate\openout\TEMP=Temp.tex \begin{document} \immediate\write\TEMP{ \def\writefoo{% I don't want to close this brace at this point }% This is suppose to close the \write command, not the \writefoo{ brace \newcommand{\foo}{This is some text} \immediate\write\TEMP{\foo} \immediate\write\TEMP{ }% This is the closing brace to the original write-out. } \end{document} I know the problem with the above code is that the \def\writefood{ closes on the } that I want to be the closing brace on the \write command, thus the \write command doesn't actually get closed. My question is, is there a way to trick latex into writing out the unbalanced brace to the file? Since it's being written out to a file it seems like this would be plausible (if you can convince latex to close the brace artificially everything else would compile fine). I tried to use \begingroup and \endgroup but that, predictably, did not work correctly as the resulting \def\writefoo's contents don't persist correctly. Edited to answer questions below thoroughly: I currently have a complex series of macros that output randomized large blocks of text, containing complex macros as well. I have managed to write them out as they are selected/generated in sequence thanks to the unexpanded command, you can see more about the specifics . However, (as it says at the bottom of that link) I want to be able to output more than one selection set. The best way that comes to mind is to define dynamically named macros that are just shells containing all the contents from a single large selection call. That way I can input the file and call the macros I want to use, and just not call the ones I want to regenerate. The problem is, since the content is generated sequentially and randomly, the only way I can think to do this is to put a \def at the start, then generate and export all the content, then close the def. But that means writing out to the file unbalanced braces which LaTeX doesn't like. | How can the special characters { and } be written literally to an external file in LaTeX, without being balanced? Obviously the following does not work: \immediate\write\my@outfile{{} \immediate\write\my@outfile{}} |
I use 64bit Ubuntu 14.04. When I run sudo apt-get update it gives the following error. Unable to find expected entry 'restricted/binary-amd64/Packages' in Release file W: Failed to fetch http://archive.ubuntukylin.com:10006/ubuntukylin/dists/trusty/Release Unable to find expected entry 'restricted/binary-amd64/Packages' in Release file (Wrong sources.list entry or malformed file) E: Some index files failed to download. They have been ignored, or old ones used instead. Could anyone tell me how to fix this problem? | I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that. I just tried to upload a screen shot but since I'm new it won't allow me to. I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following: COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse) E: The list of sources could not be read., E: The package list of status file could not be parsed or opened. How do I report bugs? What can be done about this. I have searched and everything everyone says to do leads me back to the same line error message. So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software. |
Is it possible with XeTeX to generate linearized PDF for Web streaming — showing pages sequentially as they are downloaded —, not for file size reduction? | Is it possible to create linearized PDFs (optimized for "fast web view") using TeX with free software? (I don't have Acrobat available.) |
I've been using Ubuntu 12.10 for some time now, but I am very limited when it comes to installing some software such as wine that won't run on a 64bit. I want to know what are the biggest disadvantages/advantages of both the 32 and 64 bit. Will it be worth switching to a 32bit? If using a 32bit will my programs still work? Will this command change completely the architecture from 64 to 32bit, or will it just add support to 32bit while keeping the 64bit? sudo dpkg --add-architecture i386 | What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them. If so, why not promote 64-bit over 32-bit? |
I read in a french book (corrected annals of centrale école) that it's not hard to prove that $\lim\limits \sqrt[n]{|\cos(n)|} = 1$ I wonder how to prove this. Thanks for any ideas. | I heard this question from a professor a couple years ago. I still think about it... Does the sequence $(a_n)_{n\in \mathbb N}$ with $$a_n=\sqrt[n]{|\sin(n)|}$$ converges ( to $1$ ) ? I believe this question is related to rational approximation. |
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