text: /*
   * This file is part of the GROMACS molecular simulation package.
   *
   * Copyright (c) 2014,2015,2017,2018,2019, by the GROMACS development team, led by
   * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   * and including many others, as listed in the AUTHORS file in the
   * top-level source directory and at http://www.gromacs.org.
   *
   * GROMACS is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public License
   * as published by the Free Software Foundation; either version 2.1
   * of the License, or (at your option) any later version.
   *
   * GROMACS is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with GROMACS; if not, see
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   * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
   *
   * If you want to redistribute modifications to GROMACS, please
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   * control is crucial - bugs must be traceable. We will be happy to
   * consider code for inclusion in the official distribution, but
   * derived work must not be called official GROMACS. Details are found
   * in the README & COPYING files - if they are missing, get the
   * official version at http://www.gromacs.org.
   *
   * To help us fund GROMACS development, we humbly ask that you cite
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   */
  /*! \internal \file
   *  \brief Function definitions for non-GPU builds
   *
   *  \author Mark Abraham <mark.j.abraham@gmail.com>
   */
  #include "gmxpre.h"
  
  #include "gpu_utils.h"
  
  #include "config.h"
  
  #include <cassert>
  
  #include "gromacs/hardware/gpu_hw_info.h"
  #include "gromacs/utility/arrayref.h"
  #include "gromacs/utility/smalloc.h"
  #include "gromacs/utility/stringutil.h"
  
  #ifdef _MSC_VER
  #pragma warning(disable: 6237)
  #endif
  
  //! Constant used to help minimize preprocessed code
  static constexpr bool c_binarySupportsGpus = (GMX_GPU != GMX_GPU_NONE);
  
  bool canPerformGpuDetection()
  {
      if (c_binarySupportsGpus &&
          getenv("GMX_DISABLE_GPU_DETECTION") == nullptr)
      {
          return isGpuDetectionFunctional(nullptr);
      }
      else
      {
          return false;
      }
  }
  
  #if GMX_GPU == GMX_GPU_NONE
  int gpu_info_get_stat(const gmx_gpu_info_t & /*unused*/, int /*unused*/)
  {
      return egpuNonexistent;
  }
  #endif
  
  void free_gpu_info(const gmx_gpu_info_t *gpu_info)
  {
      sfree(static_cast<void*>(gpu_info->gpu_dev)); //circumvent is_pod check in sfree
  }
  
  std::vector<int> getCompatibleGpus(const gmx_gpu_info_t &gpu_info)
  {
      // Possible minor over-allocation here, but not important for anything
      std::vector<int> compatibleGpus;
      compatibleGpus.reserve(gpu_info.n_dev);
      for (int i = 0; i < gpu_info.n_dev; i++)
      {
          assert(gpu_info.gpu_dev);
          if (gpu_info_get_stat(gpu_info, i) == egpuCompatible)
          {
              compatibleGpus.push_back(i);
          }
      }
      return compatibleGpus;
  }
  
  const char *getGpuCompatibilityDescription(const gmx_gpu_info_t &gpu_info,
                                             int                   index)
  {
      return (index >= gpu_info.n_dev ?
              gpu_detect_res_str[egpuNonexistent] :
              gpu_detect_res_str[gpu_info_get_stat(gpu_info, index)]);
  }
  /*! \brief Help build a descriptive message in \c error if there are
   * \c errorReasons why nonbondeds on a GPU are not supported.
   *
   * \returns Whether the lack of errorReasons indicate there is support. */
  static bool
  addMessageIfNotSupported(gmx::ArrayRef <const std::string> errorReasons,
                           std::string                      *error)
  {
      bool isSupported = errorReasons.empty();
      if (!isSupported && error)
      {
          *error  = "Nonbonded interactions cannot run on GPUs: ";
          *error += joinStrings(errorReasons, "; ") + ".";
      }
      return isSupported;
  }
  
  bool buildSupportsNonbondedOnGpu(std::string *error)
  {
      std::vector<std::string> errorReasons;
      if (GMX_DOUBLE)
      {
          errorReasons.emplace_back("double precision");
      }
      if (!c_binarySupportsGpus)
      {
          errorReasons.emplace_back("non-GPU build of GROMACS");
      }
      return addMessageIfNotSupported(errorReasons, error);
  }
  