2.3.2 Parallelization Directives

Parallelization directives explicitly request the compiler to attempt to parallelize the DO loop or the region of code that follows the directive. The syntax differs from general directives. Parallelization directives are only recognized when compiling with -openmp. Details regarding Fortran parallelization can be found in the OpenMP API User’s Guide and the Fortran Programming Guide.

The Fortran compiler supports the OpenMP 3.0 shared memory parallelization model. Legacy Sun and Cray parallelization directives are now deprecated and should not be used.

2.3.2.1 OpenMP Parallelization Directives

The Fortran compiler recognizes the OpenMP Fortran shared memory multiprocessing API as the preferred parallel programming model. The API is specified by the OpenMP Architecture Review Board (http://www.openmp.org).

You must compile with the command-line option -xopenmp, to enable OpenMP directives. (see 3.4.149 –xopenmp[={parallel|noopt|none}].)

For more information about the OpenMP directives accepted by f95, see the OpenMP API User’s Guide.

2.3.2.2 Legacy Sun/Cray Parallelization Directives

Legacy Sun and Cray style parallelization directives are now deprecated. The OpenMP parallelization API is preferred. Information on how to migrate from legacy Sun/Cray directives to the OpenMP model appears in the OpenMP API User’s Guide.