Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 3/22/2024
Public

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mkl_get_dynamic

Determines whether Intel® oneAPI Math Kernel Library (oneMKL) is enabled to dynamically change the number of OpenMP* threads.

Syntax

ret = mkl_get_dynamic()

Fortran Include Files/Modules

  • Include file: mkl.fi
  • Module (compiled): mkl_service.mod
  • Module (source): mkl_service.f90

Description

This function returns the status of dynamic adjustment of the number of OpenMP* threads. To determine this status, the function inspects the return value of the following function call and if it is undefined, inspects the environment setting below:

NOTE:

Dynamic adjustment of the number of threads is enabled by default.

The dynamic adjustment works as follows. Suppose that the mkl_get_max_threads function returns the number of threads equal to N. If dynamic adjustment is enabled, Intel® oneAPI Math Kernel Library (oneMKL) may request up toNthreads, depending on the size of the problem. If dynamic adjustment is disabled, Intel® oneAPI Math Kernel Library (oneMKL) requests exactlyN threads for internal parallel regions (provided it uses a threaded algorithm with at least Ncomputations that can be done in parallel). However, the OpenMP* run-time library may be configured to supply fewer threads than Intel® oneAPI Math Kernel Library (oneMKL) requests, depending on the OpenMP* setting of dynamic adjustment.

Return Values

Name

Type

Description

ret

INTEGER*4

0 - Dynamic adjustment of the number of threads is disabled.

1 - Dynamic adjustment of the number of threads is enabled.

Example

use mkl_service
integer(4) :: nt
…
nt = mkl_get_max_threads()
if (1 == mkl_get_dynamic()) then
  print '("Intel MKL may use less than "I0" threads for a large problem")', nt
else
  print '("Intel MKL should use "I0" threads for a large problem")', nt
end if