3.5 Compiling a Program for Parallel Execution Using kapf

To compile a program for parallel execution using kapf , use the following commands:

kapf /conc /cmp=myprog_mp.f myprog.f

fort myprog_mp.f /fast/optimize=(tune=host,level=5) /automatic

link myprog_cmp.obj/threads_enable/EXECUTABLE=myprog.exe,SYS$COMMON:[SYSLIB]kmp/lib

The compiler and linker qualifiers are as follows:

• /automatic - Tells the compiler to allocate local variables on the run-time stack.

• /conc - Tells KAP to restructure source code for parallel processing.

• /cmp - Causes KAP to save the optimized source program under the file name of your choice. The kapf default is to name the optimized source file_name_cmp . Because the Fortran compiler will not process a file with the default extension of .cmp , you must override the default by using /cmp to rename the optimized source file_ name_cmp.f .

• /fast - Sets the following qualifiers that can improve run-time performance: /alignment=natural , assume=noaccuracy_sensitive , math_ library=fast , and /optimize=level=4 .

• /sys$common:[syslib]kmp.olb - Tells the linker to use the KAP parallel processing library for OpenVMS Alpha. The parallel processing library provides an interface to DECthreads. See Section 3.1 for more information.

• /threads_enable - Tells the linker to allow a multithreaded application to have a thread executing on every CPU in a multiprocessor system. See Section 3.1 for more information.

• /optimize=(tune=host,level=5) - Tells the compiler to optimize for the architecture of the host processor. Note that the Fortran /optimize=(tune=host,level=5) qualifiers and the KAP Fortran /tune qualifier work independently and perform different optimizations. For information about the KAP Fortran /tune qualifier, see Section 5.1.7.

Note

When you use kapf to process a file, you must set the Fortran compiler and linker qualifiers appropriately. For this reason, Compaq recommends that you use kfort whenever possible, as kfort automatically sets the compiler and linker qualifiers correctly.

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