threadsOMP.cpp

Go to the documentation of this file.

/****************************************************************************
 *   This file is part of the aGrUM/pyAgrum library.                        *
 *                                                                          *
 *   Copyright (c) 2005-2026 by                                             *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
 *                                                                          *
 *   The aGrUM/pyAgrum library is free software; you can redistribute it    *
 *   and/or modify it under the terms of either :                           *
 *                                                                          *
 *    - the GNU Lesser General Public License as published by               *
 *      the Free Software Foundation, either version 3 of the License,      *
 *      or (at your option) any later version,                              *
 *    - the MIT license (MIT),                                              *
 *    - or both in dual license, as here.                                   *
 *                                                                          *
 *   (see https://agrum.gitlab.io/articles/dual-licenses-lgplv3mit.html)    *
 *                                                                          *
 *   This aGrUM/pyAgrum library is distributed in the hope that it will be  *
 *   useful, but WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,          *
 *   INCLUDING BUT NOT LIMITED TO THE WARRANTIES MERCHANTABILITY or FITNESS *
 *   FOR A PARTICULAR PURPOSE  AND NONINFRINGEMENT. IN NO EVENT SHALL THE   *
 *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
 *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        *
 *   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR  *
 *   OTHER DEALINGS IN THE SOFTWARE.                                        *
 *                                                                          *
 *   See LICENCES for more details.                                         *
 *                                                                          *
 *   SPDX-FileCopyrightText: Copyright 2005-2026                            *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
 *   SPDX-License-Identifier: LGPL-3.0-or-later OR MIT                      *
 *                                                                          *
 *   Contact  : info_at_agrum_dot_org                                       *
 *   homepage : http://agrum.gitlab.io                                      *
 *   gitlab   : https://gitlab.com/agrumery/agrum                           *
 *                                                                          *
 ****************************************************************************/
 

#include <agrum/agrum.h>
 
#include <agrum/base/core/threads/threadsOMP.h>
 
// include the inlined functions if necessary
#ifdef GUM_NO_INLINE
#  include <agrum/base/core/threads/threadsOMP_inl.h>
#endif /* GUM_NO_INLINE */
 
namespace gum {
 
  namespace threadsOMP {
 
    namespace {
      // the number of threads used the next time we enter into a parallel region
      unsigned int _nb_threads_{getMaxNumberOfThreads()};
    }   // namespace
 
    // returns the max number of threads used by default when entering the
    // next parallel region
    unsigned int getNumberOfThreads() { return _nb_threads_; }
 
    // Set the max number of threads to be used.
    void setNumberOfThreads(unsigned int number) {
      if (number == 0) number = 1;
#ifdef _OPENMP
      omp_set_num_threads(number);
      _nb_threads_ = number;
#else
      if (number != 1) {
        GUM_ERROR(OperationNotAllowed,
                  "openMP was not enabled at compilation (or "
                  "you asked for 0 threads !)");
      }
#endif
    }
 
  }   // namespace threadsOMP
 
}   // namespace gum