nag_omp_set_num_threads (x06aa), for multi-threaded implementations, sets the number of threads to use in subsequent multi-threaded NAG Toolbox routines. Please see Multi-threaded Functions for a description of multi-threading in the NAG Toolbox.

In serial implementations of the NAG Toolbox this function has no effect.

References

None.

Parameters

Compulsory Input Parameters

1: $num$ – int64int32nag_int scalar: The number of threads to use in subsequent multi-threaded NAG routines.

Constraint: $num \geq 1$ .

Optional Input Parameters

None.

Output Parameters

1: $ifail$ – int64int32nag_int scalar: $ifail = 0$ unless the function detects an error (see Error Indicators and Warnings).

Error Indicators and Warnings

Errors or warnings detected by the function:

$ifail = 1$: Constraint: $num \geq 1$ .

$ifail = - 99$: An unexpected error has been triggered by this routine. Please contact NAG.

$ifail = - 399$: Your licence key may have expired or may not have been installed correctly.

$ifail = - 999$: Dynamic memory allocation failed.

Accuracy

Not applicable.

Further Comments

None.

Example

In this example we presume a multi-threaded implementation of the NAG Toolbox. We set the number of threads to use in the Toolbox to

5

with a call to nag_omp_set_num_threads (x06aa) and retrieve it again with nag_omp_get_max_threads (x06ac).

Open in the MATLAB editor: x06aa_example

function x06aa_example


fprintf('x06aa example results\n\n');

% The number of threads to set
num_set = int64(5);

% Set the number of threads to use
ifail = x06aa(num_set);

% Retrieve the number of threads to use
num_max = x06ac();

if (ifail == 0)
  fprintf('\nThe number of threads to use for NAG routines:  %d\n', num_max);
end

x06aa example results


The number of threads to use for NAG routines:  5

PDF version (NAG web site, 64-bit version, 64-bit version)

Chapter Contents

Chapter Introduction

NAG Toolbox