Search results
Results From The WOW.Com Content Network
The end-loop marker specifies the name of the index variable, which must correspond to the name of the index variable at the start of the for-loop. Some languages (PL/I, Fortran 95, and later) allow a statement label at the start of a for-loop that can be matched by the compiler against the same text on the corresponding end-loop statement.
if j is less than 79 increase j by 2, set i to j, and repeat from the loop start, otherwise repeat from the beginning. EXECUTE The program READ s a single card and assigns the string data found on it to the variable named RECORD .
A reinforcing loop is a cycle in which the effect of a variation in any variable propagates through the loop and returns to reinforce the initial deviation (i.e. if a variable increases in a reinforcing loop the effect through the cycle will return an increase to the same variable and vice versa). A balancing loop is the cycle in which the ...
For example, a single statement within an outer loop ' for i := 0 to n ' and an inner loop ' for j := 0 to i+2 ' is executed once for each (i, j) pair such that 0 <= i <= n and 0 <= j <= i+2. Once again, a transformation is legal if it preserves the temporal sequence of all dependencies. Estimating the benefits of a transformation, or finding ...
The goal of loop unwinding is to increase a program's speed by reducing or eliminating instructions that control the loop, such as pointer arithmetic and "end of loop" tests on each iteration; [2] reducing branch penalties; as well as hiding latencies, including the delay in reading data from memory. [3]
Loop interchange on this example can improve the cache performance of accessing b(j,i), but it will ruin the reuse of a(i) and c(i) in the inner loop, as it introduces two extra loads (for a(i) and for c(i)) and one extra store (for a(i)) during each iteration. As a result, the overall performance may be degraded after loop interchange.
In computer science, an induction variable is a variable that gets increased or decreased by a fixed amount on every iteration of a loop or is a linear function of another induction variable. [ 1 ] For example, in the following loop, i and j are induction variables:
2.5.1 For loop. 2.5.2 FOR IN Loop. ... Increase or decrease the variable by one. These operators can be used for pre-incrementing or decrementing (as in x = ++ i ...