QUAD
A Program to Estimate an Integral

QUAD is intended to be a program that estimates the integral of a function f(x) from A to B, prints the result, the elapsed wallclock time, and the corresponding MegaFLOPS rate.

This directory contains only partial programs - they are just sketches of the code, and you will need to finish them, adding declarations, computational statements, and print statements.

Assignment:

Choose a partial program in your favorite language.

• finish the program so that it computes the integral estimate of

  f(x) = 50 / pi / ( 2500 * x * x + 1 )

• add timing calls and determine the number of FLOPS in your integration loop, so that you can print the integral estimate, the error, the wallclock time, and the MFLOPS rate.
• Make an OpenMP version of your program. You will need an "include" file. You will need to add some OpenMP directives on the integration loop. You will use the wall clock time, which OpenMP returns as

  wtime = omp_get_wtime ( )

  Try your OpenMP program on 1, 2, 4, and 8 processors, and examine the speedup.

Source Code:

• quad.c, the C source code.
• quad.cc, the C++ source code.
• quad.f, the FORTRAN77 source code.
• quad.f90, the FORTRAN90 source code.

Completed Source Code:

If you want to see how I completed the programs, you can:

• quad_complete.c, the C source code.
• quad_complete.cc, the C++ source code.
• quad_complete.f, the FORTRAN77 source code.
• quad_complete.f90, the FORTRAN90 source code.

Batch Script:

Once you have made a quad executable, you need to copy this script file to the same directory that contains the executable, and issue the command qsub quad.sh. That submits a request to have the executable program run on 4 processors. You can type showq to see if the request has started yet.

• quad.sh, a script to run the program.

You can go up one level to the HPPC 2008 web page.