the loop which execute once before condition is checked
post-test loop
3508081
loops check the condition after the block is executed, the control structure is often also known as a post-test loop. Contrast with the [[while loop]], which tests the condition before the code within the block is executed, the do-while loop is an exit-condition loop. This means that the code must always be executed first and then the expression or test condition is evaluated. If it is true, the code executes the body of the loop again. This process is repeated as long as the expression evaluates to true. If the expression is false, the loop terminates and control transfers to
Do while loop
3508081
loops check the condition after the block is executed, the control structure is often also known as a post-test loop. Contrast with the [[while loop]], which tests the condition before the code within the block is executed, the do-while loop is an exit-condition loop. This means that the code must always be executed first and then the expression or test condition is evaluated. If it is true, the code executes the body of the loop again. This process is repeated as long as the expression evaluates to true. If the expression is false, the loop terminates and control transfers to
Do while loop
2642996
this with the "do while" loop, which tests the condition/expression "after" the loop has executed. For example, in the C programming language (as well as Java, C#, Objective-C, and C++, which use the same syntax in this case), the code fragment first checks whether x is less than 5, which it is, so then the {loop body} is entered, where the "printf" function is run and x is incremented by 1. After completing all the statements in the loop body, the condition, (x < 5), is checked again, and the loop is executed again, this process repeating until the variable
While loop
10213019
Manifest expression A manifest expression is a programming language construct that a compiler can analyse to deduce which values it can take without having to execute the program. This information can enable compiler optimizations, in particular loop nest optimization, and parallelization through data dependency analysis. An expression is called manifest if it is computed only from outer loop counters and constants (a more formal definition is given below). When all control flow for a loop or condition is regulated by manifest expressions, it is called a manifest loop resp. condition. Most practical applications of manifest expressions also require the expression
Manifest expression
3508083
that allows termination of the loop. Some languages may use a different naming convention for this type of loop. For example, the [[Pascal programming language|Pascal]] language has a ""repeat until"" loop, which continues to run "until" the control expression is true (and then terminates) — whereas a "while" loop runs "while" the control expression is true (and terminates once the expression becomes false). do { } while (condition); is equivalent to(==/===) do_work(); while (condition) { In this manner, the do ... while loop saves the initial "loop priming" with codice_1 on the line before the codice_2 loop. As long as
Do while loop
892723
AppleScript comes in several slightly different flavors. They all execute the block between repeat and end repeat lines a number of times. The looping can be prematurely stopped with command exit repeat. Repeat forever. Repeat a given number of times. Conditional loops. The block inside repeat while loop executes as long as the condition evaluates to true. The condition is re-evaluated after each execution of the block. The repeat until loop is otherwise identical, but the block is executed as long as the condition evaluates to false. Loop with a variable. When starting the loop, the variable is assigned to
AppleScript
3347828
loop and the For loop are the two most common types of conditional loops in most programming languages. The following types are written in Java, but apply to multiple languages. Checks condition for truthfulness before executing any of the code in the loop. If condition is initially false, the code inside the loop will never be executed. In PL/I this is a codice_1 statement. Checks condition for truthfulness after executing the code in the loop. Therefore, the code inside the loop will always be executed at least once. PL/I implements this as a codice_2 statement. A simplified way to create
Conditional loop
15114991
it may execute a blue loop and crosses the instability strip again, once while evolving to high temperatures and again evolving back towards the asymptotic giant branch. Stars more massive than about start core helium burning before reaching the red giant branch and become red supergiants, but may still execute a blue loop through the instability strip. The duration and even existence of blue loops is very sensitive to the mass, metallicity, and helium abundance of the star. In some cases, stars may cross the instability strip for a fourth and fifth time when helium shell burning starts. The rate
Classical Cepheid variable
5101369
repeatedly executes the loop body as long as the controlling expression is true. The condition is evaluated before the loop body. until is similar, but executes the loop body as long as the condition is false. The "label" "block" construct is a bit of an oddity: Perl treats a bare block – with or without a label – as a loop that is executed once. This means that the loop control keywords can be used to restart the block or to exit it prematurely; a bare block can also have a continue block. Perl provides three loop control keywords that
Perl control structures
3347829
a while loop. a is executed just once before the loop. b is the condition of the loop. c is executed at the end of every loop. So for example, the following while loop: Could be written as the following for loop: A for-each loop is essentially equivalent to an iterator. It allows a program to iterate through a data structure without having to keep track of an index. It is especially useful in Sets which do not have indices. An example is as follows: The following is a C-style While loop. It continues looping while x does not equal
Conditional loop
556892
in evaluating the terminating condition can also cause this problem. Here is an example (in [[C (programming language)|C]]): On some systems, this loop will execute ten times as expected, but on other systems it will never terminate. The problem is that the loop terminating condition (x != 1.1) tests for exact equality of two [[floating point]] values, and the way floating point values are represented in many computers will make this test fail, because they cannot represent the value 0.1 exactly, thus introducing rounding errors on each increment (the x += 0.1 statement). The same can happen in [[Python (programming
Infinite loop
6367673
and are usually implemented by a main loop, though they are typically applied to different domains. The condition/action model is also similar to aspect-oriented programming, where when a join point (condition) is reached, a pointcut (action) is executed. A similar paradigm is used in some tracing frameworks such as DTrace, where one lists probes (instrumentation points) and associated actions, which execute when the condition is satisfied. Adapting abstract data type design methods to object-oriented programming results in a data-driven design. This type of design is sometimes used in object-oriented programming to define classes during the conception of a piece of
Data-driven programming
2350236
simply a short term memory structure that will contain a record of the elements of the states visited. The core algorithmic loop starts in line 5. This loop will continue searching for an optimal solution until a user-specified stopping condition is met (two examples of such conditions are a simple time limit or a threshold on the fitness score). The neighboring solutions are checked for tabu elements in line 8. Additionally, the algorithm keeps track of the best solution in the neighborhood, that is not tabu. The fitness function is generally a mathematical function, which returns a score or the
Tabu search
3930188
the execution to proceed to the next label, however, a warning will usually be reported during compilation. switch (ch) { Iteration statements are statements that are repeatedly executed when a given condition is evaluated as true. Since J2SE 5.0, Java has four forms of such statements. In the codice_38 loop, the test is done before each iteration. In the codice_40 loop, the test is done after each iteration. Consequently, the code is always executed at least once. codice_42 loops in Java include an initializer, a condition and a counter expression. It is possible to include several expressions of the same
Java syntax
2643035
such a loop was to be the evaluation of "first", "last" and "step" and the calculation of an iteration count via something like "(last - first)/step" once only at the start, then if those items were simple variables and their values were somehow adjusted during the iterations, this would have no effect on the iteration count even if the element selected for division by "A(last)" changed. PL/I and Algol 68, allows loops in which the loop variable is iterated over a list of ranges of values instead of a single range. The following PL/I example will execute the loop with
For loop
2642995
While loop In most computer programming languages, a while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The "while" loop can be thought of as a repeating if statement. The "while" construct consists of a block of code and a condition/expression. The condition/expression is evaluated, and if the condition/expression is "true", the code within the block is executed. This repeats until the condition/expression becomes false. Because the "while" loop checks the condition/expression before the block is executed, the control structure is often also known as a pre-test loop. Compare
While loop
560847
in SQL's codice_51 statement. A loop is a sequence of statements which is specified once but which may be carried out several times in succession. The code "inside" the loop (the "body" of the loop, shown below as "xxx") is obeyed a specified number of times, or once for each of a collection of items, or until some condition is met, or indefinitely. In functional programming languages, such as Haskell and Scheme, loops can be expressed by using recursion or fixed point iteration rather than explicit looping constructs. Tail recursion is a special case of recursion which can be easily
Control flow
3508080
Do while loop In most [[computer programming]] languages, a do while loop is a [[control flow]] [[statement (computer science)|statement]] that executes a block of code at least once, and then repeatedly executes the block, or not, depending on a given [[Boolean data type|boolean]] condition at the end of the block. The "do while" construct consists of a process symbol and a condition. First, the code within the block is executed, and then the condition is evaluated. If the condition is [[Truth|true]] the code within the block is executed again. This repeats until the condition becomes [[False (logic)|false]]. Because do while
Do while loop
2608513
sub-statement is executed repeatedly so long as the value of the expression remains non-zero (equivalent to true). With while, the test, including all side effects from <expression>, occurs before each iteration (execution of <statement>); with do, the test occurs after each iteration. Thus, a do statement always executes its sub-statement at least once, whereas while may not execute the sub-statement at all. The statement: is equivalent to: except for the behaviour of a continue; statement (which in the for loop jumps to e3 instead of e2). If e2 is blank, it would have to be replaced with a 1. Any
C syntax
2643019
condition checks a condition, and quits the loop if false. The afterthought is performed exactly once every time the loop ends and then repeats. Here is an example of the traditional for-loop in [[Java (programming language)|Java]]. // Prints the numbers 0 to 99 (and not 100), each followed by a space. for (int i=0; i<100; i++) System.out.println(); These loops are also sometimes called numeric for-loops when contrasted with foreach loops(see below). This type of for-loop is a generalisation of the numeric range type of for-loop, as it allows for the enumeration of sets of items other than number sequences. It
For loop
2935535
Loop invariant In computer science, a loop invariant is a property of a program loop that is true before (and after) each iteration. It is a logical assertion, sometimes checked within the code by an assertion call. Knowing its invariant(s) is essential in understanding the effect of a loop. In formal program verification, particularly the Floyd-Hoare approach, loop invariants are expressed by formal predicate logic and used to prove properties of loops and by extension algorithms that employ loops (usually correctness properties). The loop invariants will be true on entry into a loop and following each iteration, so that on
Loop invariant
24546
forth. In the algorithm above, steps 1, 2 and 7 will only be run once. For a worst-case evaluation, it should be assumed that step 3 will be run as well. Thus the total amount of time to run steps 1-3 and step 7 is: The loops in steps 4, 5 and 6 are trickier to evaluate. The outer loop test in step 4 will execute ( "n" + 1 ) times (note that an extra step is required to terminate the for loop, hence n + 1 and not n executions), which will consume "T"( "n" + 1 )
Analysis of algorithms
3667474
calls. Common methods to describe the syntax of statements are Backus–Naur form and syntax diagrams. Semantically many statements differ from subroutine calls by their handling of parameters. Usually an actual subroutine parameter is evaluated once before the subroutine is called. This contrasts to many statement parameters that can be evaluated several times (e.g. the condition of a while loop) or not at all (e.g. the loop body of a while loop). Technically such statement parameters are call-by-name parameters. Call-by-name parameters are evaluated when needed (see also lazy evaluation). When call-by-name parameters are available a statement like behaviour can be implemented
Statement (computer science)
1710966
be faster only when the modification will occur rarely, such as in the case of a state switching inside an inner loop. Most modern processors load the machine code before they execute it, which means that if an instruction that is too near the instruction pointer is modified, the processor will not notice, but instead execute the code as it was "before" it was modified. See prefetch input queue (PIQ). PC processors must handle self-modifying code correctly for backwards compatibility reasons but they are far from efficient at doing so. The Synthesis kernel presented in Henry Massalin's Ph.D. thesis is
Self-modifying code
5880137
on which they will execute along with the time that they will execute for. The code Generator will insert special constructs in the code that will be read during execution by the scheduler. These constructs will instruct the scheduler on which core a particular task will execute along with the start and end times. A cyclic multi-threading parallelizing compiler tries to split up a loop so that each iteration can be executed on a separate processor concurrently. The "compiler" usually conducts two passes of analysis before actual parallelization in order to determine the following: The first pass of the compiler
Automatic parallelization
5051010
back. The test is performed again and, if the condition is still unfulfilled, it processes again. If at any stage the condition is fulfilled the program skips the process blocks and continues onto the next block. The test last block is simply reversed, the process blocks are completed before the test is performed. The test last loop allows for the process blocks to be performed at least once before the first test. Concurrent execution can be drawn like this: Nassi–Shneiderman diagram A Nassi–Shneiderman diagram (NSD) in computer programming is a graphical design representation for structured programming. This type of diagram
Nassi–Shneiderman diagram
3805575
is often stored in a flag register but may also be located elsewhere. A flag register design is simple in slower, simple computers. In fast computers a flag register can place a bottleneck on speed, because instructions that could otherwise operate in parallel (in several execution units) need to set the flag bits in a particular sequence. There are also machines (or particular instructions) where the condition may be checked by the jump instruction itself, such as "branch <label> if register X negative". In simple computer designs, comparison branches execute more arithmetic and can use more power than flag register
Branch (computer science)
11297502
from the current index of codice_1, and increments it by 10. If statement codice_4 takes codice_5 time to execute, then the loop takes time codice_6 to execute sequentially, ignoring time taken by loop constructs. Now, consider a system with codice_7 processors where codice_8. If codice_2 threads run in parallel, the time to execute all codice_2 steps is reduced to codice_5. Less simple cases produce inconsistent, i.e. non-serializable outcomes. Consider the following loop operating on the same list codice_1. Each iteration sets the current index to be the value of the previous plus ten. When run sequentially, each iteration is guaranteed
Loop-level parallelism
5101372
a block: The while and until modifiers test the controlling expression before executing the statement, just like their loop counterparts. However, they are not considered actual loops, so the loop control keywords next, last and redo cannot be used with them. They have special semantics when combined with the do keyword: In these constructs, the condition is tested after the block is executed, so the block always executes at least once. These modifiers cannot be nested, so the following is illegal and should be written as one of: There are two forms of goto in Perl: and The first form
Perl control structures
560861
loop invariant is an assertion which must be true before the first loop iteration and remain true after each iteration. This implies that when a loop terminates correctly, both the exit condition and the loop invariant are satisfied. Loop invariants are used to monitor specific properties of a loop during successive iterations. Some programming languages, such as Eiffel contain native support for loop variants and invariants. In other cases, support is an add-on, such as the Java Modeling Language's specification for loop statements in Java. Some Lisp dialects provide an extensive sublanguage for describing Loops. An early example can be
Control flow
1616306
instance, by having the compiler unroll loops to eliminate jumps and loop count decrements whenever the program is executed. What exactly "programming at compile-time" means can be illustrated with an example of a factorial function, which in non-template C++ can be written using recursion as follows: The code above will execute at run time to determine the factorial value of the literals 4 and 0. By using template metaprogramming and template specialization to provide the ending condition for the recursion, the factorials used in the program—ignoring any factorial not used—can be calculated at compile time by this code: The code
Template metaprogramming
15572788
the short program, under rotating his quadruple salchow and quadruple toe loop to lie in sixth with 78.34 points. The ladies' short program saw Japan's Mao Asada perfectly execute her triple axel, which has been absent since the previous Olympic season. The technical and artistic strength she displayed in her routine to the "I've got rhythm" variations by Gershwin propelled her into the lead with 74.49, 8.84 points clear of Akiko Suzuki, who scored 65.65. "This is the first time I landed my triple Axel in my short program this season. I was in good condition since I came here.
2013 Four Continents Figure Skating Championships
560848
transformed to iteration. Most programming languages have constructions for repeating a loop a certain number of times. In most cases counting can go downwards instead of upwards and step sizes other than 1 can be used. In these examples, if N < 1 then the body of loop may execute once (with I having value 1) or not at all, depending on the programming language. In many programming languages, only integers can be reliably used in a count-controlled loop. Floating-point numbers are represented imprecisely due to hardware constraints, so a loop such as<br> might be repeated 9 or 10 times,
Control flow
17840581
successfully acquired. This general problem can be abstracted as ""before," "body," and "after"" code, which normally are executed in this order, with the condition that the "after" code is called if and only if the "before" code successfully completes, regardless of whether the "body" code executes successfully or not. This is also known as "execute around" or a "code sandwich," and occurs in various other contexts, such as a temporary change of program state, or tracing entry and exit into a subroutine. However, resource management is the most commonly cited application. In aspect-oriented programming, such execute around logic is a
Resource management (computing)
14136193
a condition either before (codice_10) or after (codice_11) the list of instructions are executed: Like most languages, Rexx can loop while incrementing an index variable and stop when a limit is reached: The increment may be omitted and defaults to 1. The limit can also be omitted, which makes the loop continue forever. Rexx permits counted loops, where an expression is computed at the start of the loop and the instructions within the loop are executed that many times: Rexx can even loop until the program is terminated: A program can break out of the current loop with the codice_12
Rexx
2935544
show. The property formula_33 is another invariant of the example loop, and the trivial property formula_34 is another one. Applying the above inference rule to the former invariant yields formula_35. Applying it to invariant formula_34 yields formula_37, which is slightly more expressive. The Eiffel programming language provides native support for loop invariants. A loop invariant is expressed with the same syntax used for a class invariant. In the sample below, the loop invariant expression codice_21 must be true following the loop initialization, and after each execution of the loop body; this is checked at runtime. The Whiley programming language also
Loop invariant
5049045
not always safe to exchange the iteration variables due to dependencies between statements for the order in which they must execute. To determine whether a compiler can safely interchange loops, dependence analysis is required. Loop interchange In compiler theory, loop interchange is the process of exchanging the order of two iteration variables used by a nested loop. The variable used in the inner loop switches to the outer loop, and vice versa. It is often done to ensure that the elements of a multi-dimensional array are accessed in the order in which they are present in memory, improving locality of
Loop interchange
3508082
the statement following the do-while loop. In other words, whereas a while loop sets the truth of a statement as a [[condition precedent]] for the code's execution, a do-while loop provides for the action's ongoing execution subject to defeasance by the condition's falsity, which falsity ("i.e.", the truth of the condition's negation) is set as a [[condition subsequent]]. It is possible, and in some cases desirable, for the condition to always evaluate to true, creating an [[infinite loop]]. When such a loop is created intentionally, there is usually another control structure (such as a [[Control flow#Early exit from loops|break statement]])
Do while loop
12862587
loop-triple Axel sequence in competition. Currently, Hanyu is able to execute four different types of quadruple jumps in competition – the toe loop, Salchow, loop, and Lutz. Before the 2011–12 season, most of Hanyu's career was guided by Nanami Abe in Sendai. However, after winning bronze at the 2012 World Figure Skating Championships, Hanyu switched coaches to Brian Orser, who is known for guiding Kim Yuna to gold in the 2010 Winter Olympics. In switching, Hanyu continued to go to high school in Sendai, but also made frequent trips to Toronto Cricket, Skating and Curling Club, where Orser works as
Yuzuru Hanyu
14064030
or relying on sizes (for exit condition) that are not true any more. Normalized loop In computer science, a normalized loop (sometimes called well-behaved loop), is a loop in which the loop variable starts at 0 (or any constant) and gets incremented by one at every iteration until the exit condition is met. Normalized loops are very important for compiler theory, loop dependence analysis as they simplify the data dependence analysis. A well behaved loop is normally of the form: Because the increment is unitary and constant, it's very easy to see that, if both "a" and "b" are bigger
Normalized loop
560853
Examples include Ada (codice_55), Fortran (codice_56), Go (codice_57), and Ruby (codice_58). Often, an infinite loop is unintentionally created by a programming error in a condition-controlled loop, wherein the loop condition uses variables that never change within the loop. Sometimes within the body of a loop there is a desire to skip the remainder of the loop body and continue with the next iteration of the loop. Some languages provide a statement such as codice_59 (most languages), codice_60, or codice_61 (Perl and Ruby), which will do this. The effect is to prematurely terminate the innermost loop body and then resume as
Control flow
19721056
we can prefetch the elements that are going to be accessed in future iterations by inserting a "prefetch" instruction as shown below: for (int i=0; i<1024; i++) { Here, the prefetch stride, formula_1 depends on two factors, the cache miss penalty and the time it takes to execute a single iteration of the for loop. For instance, if one iteration of the loop takes 7 cycles to execute, and the cache miss penalty is 49 cycles then we should have formula_6 - which means that we prefetch 7 elements ahead. With the first iteration, i will be 0, so we
Cache prefetching
2935542
each iteration of the loop body, and also after each iteration of the loop body. Since a codice_17 loop is precisely the repeated iteration of the loop body, it follows that if the invariant is true before entering the loop, it must also be true after exiting the loop. The following example illustrates how this rule works. Consider the program One can then prove the following Hoare triple: The condition "C" of the codice_17 loop is formula_21. A useful loop invariant formula_2 has to be guessed; it will turn out that formula_23 is appropriate. Under these assumptions it is possible
Loop invariant
12186968
language. The transformation and generation systems can typically handle imperfectly nested loops. To compare the constraint-based polyhedral model to prior approaches such as individual loop transformations and the unimodular approach, consider the question of whether we can parallelize (execute simultaneously) the iterations of following contrived but simple loop: Approaches that cannot represent symbolic terms (such as the loop-invariant quantity N in the loop bound and subscript) cannot reason about dependencies in this loop. They will either conservatively refuse to run it in parallel, or in some cases speculatively run it completely in parallel, determine that this was invalid, and re-execute
Frameworks supporting the polyhedral model
4268660
duty to an end whereas a condition precedent initiates a duty. In computing, a while loop sets the truth of a statement as a condition precedent for the execution of a given subroutine or other code segment. By contrast, a do while loop provides for the action's ongoing execution unless a given condition is determined to be false, "i.e.", provides for that action's execution subject to defeasance by the condition's falsity, which falsity ("i.e.", the truth of the condition's negation) is set as a condition subsequent. Condition precedent A condition precedent is an event or state of affairs that is
Condition precedent
3385228
The third condition is to handle the case where "G"/Γ is not compact but has cusps. The formulation requires the general notion of "factor of automorphy" "j" for Γ, which is a type of 1-cocycle in the language of group cohomology. The values of "j" may be complex numbers, or in fact complex square matrices, corresponding to the possibility of vector-valued automorphic forms. The cocycle condition imposed on the factor of automorphy is something that can be routinely checked, when "j" is derived from a Jacobian matrix, by means of the chain rule. Before this very general setting was proposed
Automorphic form
20996891
Loop-and-a-half Loop-and-a-half is a computer science term for a control flow construct where a loop is exited in the middle, instead of at the beginning or at the end. This kind of logic is needed for example when processing an unknown number of data items until a certain condition becomes true indicating that there are no more items to process. Usually the exit condition has to do with the data items, for example looking for a particular item called the sentinel which indicates the end of the items. Writing a loop-and-a-half in a simplistic manner leads to code duplication which
Loop-and-a-half
6186753
the convicted, not to mention a veto of legislation", observing that the U.S. Constitution does not ask the President to take an oath to execute the laws, but rather, to execute "the "office" of the president, which is larger." Referring to domestic surveillance, Mansfield notes, "those arguing that the executive should be subject to checks and balances are wrong to say or imply that the president may be checked in the sense of stopped. The president can be held accountable and made responsible, but if he could be stopped, the Constitution would lack any sure means of emergency action. He
Harvey Mansfield
3347830
3, or in other words it only stops looping when x equals 3. However, since x is initialized to 0 and the value of x is never changed in the loop, the loop will never end (infinite loop). The while loop below will execute the code in the loop 5 times. x is initialized to 0, and each time in the loop the value of x is incremented. The while loop is set up to stop when x is equal to 5. Conditional loops are often the source of an Off by one error. Conditional loop In computer programming, conditional
Conditional loop
3413093
28, it became a hurricane. Later that day, sustained winds peaked at 85 mph (140 km/h). Between October 28 and October 29, the storm executed a cyclonic loop just offshore Louisiana. Shortly before 1200 UTC on that day, Juan made landfall near Morgan City, Louisiana as a minimal hurricane. It quickly weakened back to a tropical storm. The storm began to execute another cyclonic loop, reaching the Lafayette area before curving back out to the Gulf of Mexico on October 30. The storm briefly remained offshore, before a second landfall on the Mississippi River Delta in Louisiana early on October
1985 Atlantic hurricane season
17282995
infinite times, or add a condition which will make the code inside it execute only if the condition is matched. There is 1 exception, the “Create a Clone” block creates a clone of the object. The clone will not execute any of the code programmed for the original object. That’s the job of the “When object is cloned” block. Drawing blocks in Hopscotch work similar to the turtle module in Python, allowing easy and more complex art to be coded. The Hopscotch player activates the blocks in the scripts upon activation of their individual triggers. The "player" is also available
Hopscotch (programming language)
5101367
Perl control structures The basic control structures of Perl are similar to those used in C and Java, but they have been extended in several ways. In the following, "label" is an optional identifier terminated by a colon, and "block" is a sequence of one of more Perl statements surrounded by braces. All looping constructs except for the C-style for-loop can have a continue block that is executed after each iteration of the loop body, before the loop condition is evaluated again. This is the so-called C-style for loop. The first expression is evaluated prior to the first loop iteration.
Perl control structures
20843625
speed of . Exiting the tunnel, the train rises into a Immelmann loop. The inversion happens to be the second tallest inversion on a Dive Coaster, with Valravn at Cedar Point having a Immelmann Loop. Yukon Striker's Immelmann loop is however the largest inversion on a Dive Coaster at in diameter due to the element extending from the underwater tunnel. Following the Immelmann loop, the train plunges down towards the ground again, crossing over Vortex once more, before entering a zero-g roll. This is followed by a vertical loop, which is the first on a Dive Coaster, then a second
Yukon Striker
2643041
be If the PERFORM verb has the optional clause TEST AFTER, the resulting loop is slightly different: the loop body is executed at least once, before any test. Loops in [[BASIC]] are sometimes called for-next loops. 10 REM THIS FOR LOOP PRINTS ODD NUMBERS FROM 1 TO 15 20 FOR I = 1 TO 15 STEP 2 30 PRINT I 40 NEXT I Notice that the end-loop marker specifies the name of the index variable, which must correspond to the name of the index variable in the start of the for-loop. Some languages (PL/I, FORTRAN 95 and later) allow a
For loop
2356973
real value. For each point of the root locus a value of formula_14 can be calculated. This is known as the magnitude condition. The root locus only gives the location of closed loop poles as the gain formula_14 is varied. The value of formula_14 does not affect the location of the zeros. The open-loop zeros are the same as the closed-loop zeros. A point formula_22 of the complex "s"-plane satisfies the angle condition if which is the same as saying that that is, the sum of the angles from the open-loop zeros to the point formula_22 minus the angles from
Root locus
8191747
gain "K" is usually parameterized. Each point on the locus satisfies the angle condition and magnitude condition and corresponds to a different value of "K". For negative feedback systems, the closed-loop poles move along the root-locus from the open-loop poles to the open-loop zeroes as the gain is increased. For this reason, the root-locus is often used for design of proportional control, i.e. those for which formula_1. Consider a simple feedback system with controller formula_1, plant formula_3 and transfer function formula_4 in the feedback path. Note that a unity feedback system has formula_5 and the block is omitted. For this
Closed-loop pole
566257
double square brackets. The factorial function is implemented as a function in this example: function factorial(n) end Lua has four types of loops: the while loop, the repeat loop (similar to a do while loop), the numeric for loop, and the generic for loop. --condition = true while condition do end repeat until condition for i = first, last, delta do --delta may be negative, allowing the for loop to count down or up end The generic for loop: for key, value in pairs(_G) do end would iterate over the table _G using the standard iterator function pairs, until it
Lua (programming language)
14964504
as a moderately strong Category 2 hurricane on the Saffir-Simpson Hurricane Scale on October 12. On the following day, Josephine weakened back to a Category 1 hurricane before becoming nearly stationary. It later headed northeastward and paralleled the coast well offshore of Nova Scotia. By October 17, Josephine weakened back to a tropical storm, shortly before beginning to execute a cyclonic loop to the south of Newfoundland. While executing the cyclonic loop, Josephine became extratropical on October 18. Although Josephine remained well offshore of the eastern United States, the effects from the storm and an area of high pressure produced
Hurricane Josephine (1984)
4553453
first three lines making out the condition. The only statements in the loop that can possibly affect the invariants are in the last two lines, and these can be shown to preserve the truth of both invariants as long as the first three lines have executed successfully without breaking out of the loop. A third invariant for the body of the loop (up to floating point precision) is formula_14 but since is halved at the beginning of the loop before any conditions are tested, our conclusion is only that formula_15 at the termination of the loop. To prove termination, it
Minkowski's question-mark function
4582142
coders were able to write replacement Xbox GUIs (known as dashboards), games and applications for the Xbox. A softmod which uses a commercial game such as "", "Mech Assault" or "Splinter Cell" to load up homebrew software has been discovered. This method utilizes modified font bug and sound bug to cause the Xbox to cause a stack buffer overflow and load one of the homebrew dashboards. Once in this condition, the Xbox is able to execute homebrew games and applications. Because the Xbox uses standard PC libraries, writing homebrew games is relatively easy, as the vast majority of libraries available
Homebrew (video games)
10243248
GCD test In compiler theory of computer science, A Greatest common divisor Test is the test used in study of loop optimization and loop dependence analysis to test the dependency between loop statements. Whenever a sequential loop like for loop is made to be parallel so that it can be executed on more than one processor like in case of grid computing or cluster computing then certain dependencies are checked to know whether this loop can be parallelized or not: for instance, testing the flow (true) dependence of a statement. According to this test, by comparing the indices of two
GCD test
2015464
immediately return from a stored procedure or function. codice_6 ends the enclosing codice_13 loop, while codice_7 causes the next iteration of the loop to execute. An example of a codice_13 loop is given below. DECLARE @i INT SET @i = 0 WHILE @i < 5 BEGIN END In Transact-SQL, both the codice_27 and codice_28 statements allow a codice_29 clause to be added, which allows joins to be included. This example deletes all codice_30 who have been flagged with the 'Idle' flag. DELETE u codice_31 is a Transact-SQL statement that implements a bulk data-loading process, inserting multiple rows into a table,
Transact-SQL
3476926
checking in the inner loop in fact, the tags need not even be read. Later in the pipeline, but before the load instruction is retired, the tag for the loaded data must be read, and checked against the virtual address to make sure there was a cache hit. On a miss, the cache is updated with the requested cache line and the pipeline is restarted. An associative cache is more complicated, because some form of tag must be read to determine which entry of the cache to select. An N-way set-associative level-1 cache usually reads all N possible tags and
CPU cache
467256
attacks on October 7. The hospital, which had been issuing reassuring bulletins to the public, was now forced to inform the public that Willkie's condition had worsened and that he was critically ill. The next morning, Willkie suffered one last attack which proved fatal. From the time he checked into Lenox Hill Hospital, he was said to have suffered over a dozen heart attacks. Roosevelt released a statement applauding Willkie's "tremendous courage" which "prompted him more than once to stand alone ... In this hour of grave crisis the nation loses a great citizen." War Secretary Stimson offered to have
Wendell Willkie
5945952
ridge of high pressure strengthened to the north of the storm, leaving weaker steering currents. This caused Hurricane Easy to execute a counter-clockwise loop to the west of Tampa, Florida. After executing its first loop, Hurricane Easy moved northeastward at until making landfall near Cedar Key on September 5 with winds of . Steering currents again became weak, causing Easy to execute a second loop in 24 hours towards the southeast. After briefly emerging into the Gulf of Mexico, the hurricane made its final landfall on Homosassa Springs to the north of Tampa, and rapidly weakened to a tropical storm
Hurricane Easy (1950)
2935539
loop condition codice_4 in line 5 should better be modified to codice_8, in order to avoid endless looping for illegitimate negative values of codice_3. While this change in code intuitively shouldn't make a difference, the reasoning leading to its correctness becomes somewhat more complicated, since then only codice_10 is known in line 13. In order to obtain that also codice_11 holds, that condition has to be included into the loop invariant. It is easy to see that codice_11, too, is an invariant of the loop, since codice_8 in line 6 can be obtained from the (modified) loop condition in line
Loop invariant
556882
loops are one possible cause for a computer "[[hang (computing)|freezing]]"; others include [[thrashing (computer science)|thrashing]], [[deadlock]], and [[segmentation fault|access violation]]s. Looping is repeating a set of instructions until a specific condition is met. An infinite loop occurs when the condition will never be met, due to some inherent characteristic of the loop. There are a few situations when this is desired behavior. For example, the games on cartridge-based game consoles typically have no exit condition in their main loop, as there is no operating system for the program to exit to; the loop runs until the console is powered off.
Infinite loop
11297503
that the previous iteration will already have the correct value. With multiple threads, process scheduling and other considerations prevent the execution order from guaranteeing an iteration will execute only after its dependence is met. It very well may happen before, leading to unexpected results. Serializability can be restored by adding synchronization to preserve the dependence on previous iterations. There are several types of dependences that can be found within code. In order to preserve the sequential behaviour of a loop when run in parallel, True Dependence must be preserved. Anti-Dependence and Output Dependence can be dealt with by giving each
Loop-level parallelism
4220794
testosterone in the patient's blood. Abnormally high levels of any of these hormones help in diagnosing hyperandrogenism. Since risk factors are not known and vary among individuals with hyperandrogenism, there is no sure method to prevent this medical condition. Therefore, more longterm studies are needed first to find a cause for the condition before being able to find a sufficient method of prevention. However, there are a few things that can help avoid long-term medical issues related to hyperandrogenism like PCOS. Getting checked by a medical professional for hyperandrogenism; especially if one has a family history of the condition, irregular
Hyperandrogenism
16280876
GPU, on which to allocate memory and execute), and codice_9 (view of an accelerator). There is also a global function, codice_10, which you use to write a C++ AMP parallel loop. C++ AMP C++ Accelerated Massive Parallelism (C++ AMP) is a native programming model that contains elements that span the C++ programming language and its runtime library. It provides an easy way to write programs that compile and execute on data-parallel hardware, such as graphics cards (GPUs). C++ AMP is a library implemented on DirectX 11 and an open specification from Microsoft for implementing data parallelism directly in C++. It
C++ AMP
8942452
positive adjustment is in the clockwise direction. where The clockwise specifier (c) means only the flows that are moving clockwise in our loop, while the counter-clockwise specifier (cc) is only the flows that are moving counter-clockwise. This adjustment doesn't solve the problem, since most networks have several loops. It is okay to use this adjustment, however, because the flow changes won't alter condition 1, and therefore, the other loops still satisfy condition 1. However, we should use the results from the first loop before we progress to other loops. An adaptation of this method is needed to account for water
Pipe network analysis
620795
realize that this condition is a sufficient, not a necessary condition. That means that neighbors which satisfy this condition are guaranteed to be on a loop-free path to some destination, however, there may be also other neighbors on a loop-free path which do not satisfy this condition. However, such neighbors do not provide the shortest path to a destination, therefore, not using them does not present any significant impairment of the network functionality. These neighbors will be re-evaluated for possible usage if the router transitions to Active state for that destination. EIGRP features load balancing on paths with different costs.
Enhanced Interior Gateway Routing Protocol
1949102
stale. Thus, a processor under PC can execute a younger load when an older store needs to be stalled. Read before Write, Read after Read and Write before Write ordering is still preserved in this model. The processor consistency model is similar to PRAM consistency model with a stronger condition that defines all writes to the same memory location must be seen in the same sequential order by all other processes. Processor consistency is weaker than sequential consistency but stronger than PRAM consistency model. The Stanford DASH multiprocessor system implements a variation of processor consistency which is incomparable (neither weaker
Consistency model
3277292
it will come out from loop. Similarly, processor #1's load operations may be executed out-of-order and it is possible for codice_1 to be read "before" codice_2 is checked, and again the print statement might therefore print an unexpected value. For most programs neither of these situations is acceptable. A memory barrier can be inserted before processor #2's assignment to codice_2 to ensure that the new value of codice_1 is visible to other processors at or prior to the change in the value of codice_2. Another can be inserted before processor #1's access to codice_1 to ensure the value of codice_1
Memory barrier
1846030
assistance. The train therefore set off with fifteen carriages, containing about 940 passengers. The carriages were full, and some passengers travelled with the guards. Tickets were checked before setting off and to prevent people without tickets joining the excursion, once each compartment had been checked its doors were locked. Initially, the train made progress up the steep gradient at about but stalled about before the top of the gradient. To prevent the train rolling back, the brakes were applied. The train did have continuous brakes, ("i.e.", all carriages had brakes which could be operated by the driver), but they were
Armagh rail disaster
739659
and both execute until the end of the block. Once an always block has reached its end, it is rescheduled (again). It is a common misconception to believe that an initial block will execute before an always block. In fact, it is better to think of the initial-block as a special-case of the always-block, one which terminates after it completes for the first time. These are the classic uses for these two keywords, but there are two significant additional uses. The most common of these is an always keyword without the @(...) sensitivity list. It is possible to use always
Verilog
18879630
poor condition and that no explosive materials had been found at the accident site. Rafique suggested other forms of sabotage may have been used. Bridges in Pakistan are checked four times a year. Conflicting information was given about the state of the bridge, with Rafique stating that it passed an inspection in January 2015 and was found to be "faultless". It was also reported that the bridge was reported to be in an "extremely dangerous" condition. It was subsequently reported that the locomotive hauling the train had derailed some before the bridge, which collapsed as a result of the derailed
2015 Gujranwala derailment
466737
Z80 has a single instruction that will execute the entire loop (codice_26). The data block is copied one byte at a time, and the data movement and looping logic utilizes 16-bit operations. Note that the assembled code is binary-compatible with the Intel 8080 and 8085 CPUs. Each instruction is executed in steps that are usually termed machine cycles (M-cycles), each of which can take between three and six clock periods (T-cycles). Each M-cycle corresponds roughly to one memory access or internal operation. Many instructions actually end during the M1 of the "next" instruction which is known as a "fetch/execute overlap".
Zilog Z80
4560129
not violate the consistency condition enforced by the transactional system, but it is possible for this "temporary" inconsistent state to cause a transaction to trigger a fatal exceptional condition such as a segmentation fault or even enter an endless loop, as in the following contrived example from Figure 4 of "Language Support for Lightweight Transactions": Provided "x"="y" initially, neither transaction above alters this invariant, but it is possible that transaction A will read "x" after transaction B updates it but read "y" before transaction B updates it, causing it to enter an infinite loop. The usual strategy for dealing with
Software transactional memory
14064025
Normalized loop In computer science, a normalized loop (sometimes called well-behaved loop), is a loop in which the loop variable starts at 0 (or any constant) and gets incremented by one at every iteration until the exit condition is met. Normalized loops are very important for compiler theory, loop dependence analysis as they simplify the data dependence analysis. A well behaved loop is normally of the form: Because the increment is unitary and constant, it's very easy to see that, if both "a" and "b" are bigger than MAX, this loop will never access memory outside the allocated range. A
Normalized loop
297457
called a context switch. An early model which governed the allocation of time to programs was called cooperative multitasking. In this model, when control is passed to a program by the kernel, it may execute for as long as it wants before explicitly returning control to the kernel. This means that a malicious or malfunctioning program may not only prevent any other programs from using the CPU, but it can hang the entire system if it enters an infinite loop. Modern operating systems extend the concepts of application preemption to device drivers and kernel code, so that the operating system
Operating system
9543098
environment variable NUSMV _LIBRARY_PATH or in default library path if no such variable is defined. If no such file exists, user's home directory and current directory will also be checked. Commands in the initialization file are executed consecutively. When initialization phase is completed the NuSMV shell is displayed and the system is now ready to execute user commands. A NuSMV command usually consists of a command name and arguments to the invoked command. It is possible to make NuSMV read and execute a sequence of commands from a file, through the command line option -source: When the -int option is
NuSMV
1730081
Navy psychiatrist Captain Dr. George N. Raines decided to send the former Secretary of Defense to the National Naval Medical Center (NNMC) in Bethesda, Maryland, where it would be possible to deny his mental illness. He was checked into NNMC five days later. The decision to house him on the 16th floor instead of the first floor was justified in the same way. Forrestal's condition was officially announced as "nervous and physical exhaustion"; his lead doctor, Captain Raines, diagnosed his condition as "depression" or "reactive depression". As a person who prized anonymity and once stated that his hobby was "obscurity",
James Forrestal
7394100
topspin shot can be generated by hitting the ball with an up-and-forward swing, with the racquet facing below the direction it is moving. A topspin shot is the opposite of a "slice". In competitive table tennis, effective command of topspin is indispensable, not only in order to be able to execute an attack shot counter to a backspin ball, but also in order to be able to execute a speed shot when the ball is already lower than the net. In table tennis the best defense for a top spin loop is a block close to the table which involves
Topspin
3881270
checked in octal form and/or alphabetic form with the command line tool codice_42 4701 on an executable file owned by 'root' and the group 'root' A user named 'thompson' attempts to execute the file. The executable permission for all users is set (the '1') so 'thompson' can execute the file. The file owner is 'root' and the SUID permission is set (the '4') - so the file is executed as 'root'. The reason an executable would be run as 'root' is so that it can modify specific files that the user would not normally be allowed to, without giving the
Setuid
560852
exceptional condition arises, such as an error. For instance, an event-driven program (such as a server) should loop forever, handling events as they occur, only stopping when the process is terminated by an operator. Infinite loops can be implemented using other control flow constructs. Most commonly, in unstructured programming this is jump back up (goto), while in structured programming this is an indefinite loop (while loop) set to never end, either by omitting the condition or explicitly setting it to true, as codice_54. Some languages have special constructs for infinite loops, typically by omitting the condition from an indefinite loop.
Control flow
1865927
big-O notation. Except for the fixed overhead incurred in entering and exiting the function, all the computations are performed in the codice_101 loop. To bound the number of iterations of this loop; observe that codice_86 is constructed so that if a match which had begun at codice_7 fails while comparing codice_89 to codice_12, then the next possible match must begin at codice_106. In particular, the next possible match must occur at a higher index than codice_3, so that codice_108. This fact implies that the loop can execute at most 2"n" times, since at each iteration it executes one of the
Knuth–Morris–Pratt algorithm
18236265
execute individual instructions written to a register. This may be supplemented with a data-passing register and a module to directly access the memory. Instruction feeding lets the debugger access the computer exactly as software would. It also minimizes changes in the CPU, and adapts to many types of CPU. This was said to be especially apt for RISC-V because RISC-V is explicitly designed for many types of computers. The data-passing register allows a debugger to write a data-movement loop to RAM, and then execute the loop to move data into or out of the computer at a speed near the
RISC-V
13681246
The ARMv8.3-A architecture introduces a new feature at the hardware level that takes advantage of unused bits in the pointer address space to cryptographically sign pointer addresses. Before jumping to a pointer the signature is checked and an error occurs if the check fails. Notably the latest iPhone A12 chips have upgraded to ARMv8.3 and make use of PACs. Return-oriented programming Return-oriented programming (ROP) is a computer security exploit technique that allows an attacker to execute code in the presence of security defenses such as executable space protection and code signing. In this technique, an attacker gains control of the
Return-oriented programming
7932448
£10 before Wednesday, if the £10 is paid before the end of Wednesday, a condictio could not be brought to reclaim it. A condition is when an obligation is stated as arising on an event that may or may not happen. Although you cannot withdraw from a conditional stipulation once made, no debt arises until the condition is satisfied (D.12.6.16.) An exception arises if the party prevents the condition occurring, in which case it is treated as arising already D.50.17.161.Conditions can be resolutive or suspensive. A resolutive condition is where there is an existing debt which is destroyed on the
Stipulatio
6283591
Marietta Parkway North and South Marietta Parkway form a ring road in Marietta, Georgia that was once designated as Georgia State Route 120 Loop (SR 120 Loop) before route realignments in 2007. The full loop is approximately in circumference and has an interchange with Interstate 75 (I-75) twice, once on the north side of Marietta and once on the south side. The southern segment of the road is designated as a part of SR 120 and the northern segment forms SR 120 Alternate (SR 120 Alt.). A portion of SR 5 has a concurrency with SR 120 Alt. from U.S.
Marietta Parkway
9813309
is non-interruptible due to absence of signals (other than the thread or its process being terminated), although the related SleepEx function can be used to put the thread into an alertable state, allowing APC calls being made while the thread is sleeping. Also, a thread can technically be "interrupted" in case e.g. the process terminates due to an exception in a different thread. Some system programs that never terminate execute an event loop, going to sleep at the start of each cycle and waiting for some event to awaken them. Once an event is received, the program services the event,
Sleep (system call)
20649684
executed in the loop. Therefore for this trivial parallelization formula_26 is an upper bound for the number of processors. For example, let the number of processors formula_27 be equal to the number of nodes formula_26. This results in each processor executing codice_4 exactly once in parallel. However, when there are only for example formula_29 processors available, each processor has to execute codice_4 twice. In total this yields a runtime of formula_30, when formula_26 is a multiple of formula_27. Consequently the efficiency of this parallelization is perfect: Employing formula_27 processors reduces the runtime by the factor formula_27. Another benefit of this
Parallel all-pairs shortest path algorithm
1346552
fusion. Helium fusion first begins when a star leaves the red giant branch after accumulating sufficient helium in its core to ignite it. In stars around the mass of the sun, this begins at the tip of the red giant branch with a helium flash from a degenerate helium core and the star moves to the horizontal branch where it burns helium in its core. More massive stars ignite helium in their cores without a flash and execute a blue loop before reaching the asymptotic giant branch. Despite the name, stars on a blue loop from the red giant branch
Stellar nucleosynthesis
7182273
in her programs. She landed her first triple-triple combination jump, a triple toe-triple toe combination, at age of 14 at the 2005 World Junior Championships. She is also known to practice triple axels in training. She is well known for her signature triple-triple jump combinations including triple lutz–triple toe loop, and triple flip–triple toe loop. She can also execute a triple lutz–double toe loop–double loop jump combination. Another signature jump in her repertoire is a layback Ina Bauer or spread eagle that leads to either a double axel, a double axel–triple toe loop jump combination or a double axel–double toe
Yuna Kim
3670929
may also occur with tricycle landing gear if excessive load is applied to the nosewheel, a condition known as wheel-barrowing. If the aircraft heading is different from the aircraft's direction of motion, a sideways force is exerted on the wheels. If this force is in front of the centre of gravity, the resulting moment rotates the aircraft's heading even further from its direction of motion. This increases the force and the process reinforces itself. To avoid a ground loop, the pilot must respond to any turning tendency quickly, while sufficient control authority is available to counteract it. Once the aircraft
Ground loop (aviation)
4265230
Neurapraxia Neurapraxia is a disorder of the peripheral nervous system in which there is a temporary loss of motor and sensory function due to blockage of nerve conduction, usually lasting an average of six to eight weeks before full recovery. Neurapraxia is derived from the word apraxia, meaning “loss or impairment of the ability to execute complex coordinated movements without muscular or sensory impairment”. This condition is typically caused by a blunt neural injury due to external blows or shock-like injuries to muscle fibers and skeletal nerve fibers, which leads to repeated or prolonged pressure buildup on the nerve. As
Neurapraxia
4265246
proper tackling technique by coaches and trainers. Neurapraxia Neurapraxia is a disorder of the peripheral nervous system in which there is a temporary loss of motor and sensory function due to blockage of nerve conduction, usually lasting an average of six to eight weeks before full recovery. Neurapraxia is derived from the word apraxia, meaning “loss or impairment of the ability to execute complex coordinated movements without muscular or sensory impairment”. This condition is typically caused by a blunt neural injury due to external blows or shock-like injuries to muscle fibers and skeletal nerve fibers, which leads to repeated or
Neurapraxia
3882390
to 7, that have to be produced, checked, and debugged, and the compiler may have to allocate more registers to store variables in the expanded loop iteration . In addition, the loop control variables and number of operations inside the unrolled loop structure have to be chosen carefully so that the result is indeed the same as in the original code (assuming this is a later optimization on already working code). For example, consider the implications if the iteration count were not divisible by 5. The manual amendments required also become somewhat more complicated if the test conditions are variables.
Loop unrolling
2769076
increment and the STEP keyword, the loop variable will be incremented or decremented by a different value than the default of +1. For instance, the following loop steps back from 10 to 2 by decrementing the loop index by 2: The WHILE/REPEAT/END block in RPL supports an indefinite loop with the condition test at the start of the loop. The syntax of the WHILE/REPEAT/END block is: The DO/UNTIL/END block in RPL supports an indefinite loop with the condition test at the end of the loop. The syntax of the DO/UNTIL/END block is: RPL (programming language) </ref> RPL (derived from Reverse
RPL (programming language)
5051009
Testing loops: this block allows the program to loop one or a set of processes until a particular condition is fulfilled. The process blocks covered by each loop are subset with a side-bar extending out from the condition. There are two main types of testing loops, test first and test last blocks. The only difference between the two is the order in which the steps involved are completed. In the test first situation, when the program encounters the block it tests to see if the condition is fulfilled, then, if it is not completes the process blocks and then loops
Nassi–Shneiderman diagram