mkl_set_num_threads

Specifies the number of OpenMP* threads to use.

Syntax

call mkl_set_num_threads( nt )

Fortran Include Files/Modules

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

Input Parameters

Name	Type	Description
nt	INTEGER	nt > 0 - The number of threads suggested by the user. nt≤ 0 - Invalid value, which is ignored.

Name

Type

Description

INTEGER

nt > 0 - The number of threads suggested by the user.

nt≤ 0 - Invalid value, which is ignored.

Description

This function enables you to specify how many OpenMP threads Intel MKL should use for internal parallel regions. If this number is not set (default), Intel MKL functions use the default number of threads for the OpenMP run-time library. The specified number of threads applies:

To all Intel MKL functions except the functions from the domains where the number of threads is set with mkl_domain_set_num_threads
To all execution threads except the threads where the number of threads is set with mkl_set_num_threads_local

The number specified is a hint, and Intel MKL may actually use a smaller number.

Note

This function takes precedence over the MKL_NUM_THREADS environment variable.

Example

use mkl_service
…
call mkl_set_num_threads(4)
call my_compute_using_mkl  !Intel MKL uses up to 4 OpenMP threads