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Run the following code to count the number of inverses that are not perfectly accurate:
REAL*4 X,Y,Z
INTEGER II = 0
DO X=1.0,1000.0,1.0Y = 1.0 / X
Z = Y * XIF ( Z .NE. 1.0 ) THEN
I = I + 1ENDIF
ENDDOPRINT *,’Found ’,I
END Change the type of the variables to
REAL*8 and repeat. Make sure to keep the optimization at a sufficiently low level (-00) to keep the compiler from eliminating the computations.
Write a program to determine the number of digits of precision for
REAL*4 and
REAL*8 .
Write a program to demonstrate how summing an array forward to backward and backward to forward can yield a different result.
Assuming your compiler supports varying levels of IEEE compliance, take a significant computational code and test its overall performance under the various IEEE compliance options. Do the results of the program change?
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