Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : // C++ includes
      20             : #include <algorithm>  // is_sorted, lower_bound
      21             : 
      22             : // Local includes
      23             : #include "libmesh/parallel_histogram.h"
      24             : #include "libmesh/parallel.h"
      25             : #include "libmesh/parallel_conversion_utils.h"
      26             : #include "libmesh/parallel_hilbert.h"
      27             : 
      28             : namespace libMesh
      29             : {
      30             : 
      31             : 
      32             : 
      33             : namespace Parallel {
      34             : template <typename KeyType, typename IdxType>
      35      699733 : Histogram<KeyType,IdxType>::Histogram (const Parallel::Communicator & comm_in,
      36             :                                        const std::vector<KeyType> & d) :
      37             :   ParallelObject(comm_in),
      38      699733 :   data(d)
      39             : {
      40       15284 :   libmesh_assert (std::is_sorted (data.begin(), data.end()));
      41      699733 : }
      42             : 
      43             : 
      44             : 
      45             : template <typename KeyType, typename IdxType>
      46      699733 : void Histogram<KeyType,IdxType>::make_histogram (const IdxType nbins,
      47             :                                                  KeyType max,
      48             :                                                  KeyType min)
      49             : {
      50       15284 :   libmesh_assert_less (min, max);
      51             : 
      52             :   // The width of each bin.  Store this as a floating point value
      53      715017 :   double bin_width = (Parallel::Utils::to_double(max)-
      54      699733 :                       Parallel::Utils::to_double(min))/static_cast<double>(nbins);
      55             : 
      56             : 
      57             :   // The idea for 4 bins of size d is this:
      58             :   //
      59             :   //  0          1          2           3          4
      60             :   //  |----------|----------|-----------|----------|
      61             :   // min   0   min+d  1   min+2d  2  min+3d   3   max
      62             : 
      63             : 
      64             : 
      65             :   // Set the iterators corresponding to the boundaries
      66             :   // as defined above.  This takes nbins * O(log N) time.
      67      699733 :   bin_bounds.resize (nbins+1);
      68      699733 :   bin_iters.resize  (nbins+1, data.begin());
      69             : 
      70             :   // Set the minimum bin boundary iterator
      71      699733 :   bin_iters[0]  = data.begin();
      72      699733 :   bin_bounds[0] = Parallel::Utils::to_double(min);
      73             : 
      74             :   // Set the internal bin boundary iterators
      75   360246650 :   for (IdxType b=1; b<nbins; ++b)
      76             :     {
      77   361060033 :       bin_bounds[b] = Parallel::Utils::to_double(min) + bin_width * b;
      78             : 
      79   361059835 :       bin_iters[b] =
      80   359546917 :         std::lower_bound (bin_iters[b-1], data.end(),
      81   361059835 :                           Parallel::Utils::Convert<KeyType>::to_key_type(bin_bounds[b]));
      82             :     }
      83             : 
      84      715017 :   bin_iters[nbins]  = data.end();
      85      715015 :   bin_bounds[nbins] = Parallel::Utils::to_double(max);
      86      699733 : }
      87             : 
      88             : 
      89             : 
      90             : template <typename KeyType, typename IdxType>
      91      699733 : void Histogram<KeyType,IdxType>::build_histogram ()
      92             : {
      93             :   // Build a local histogram
      94      715017 :   std::vector<IdxType> local_hist (this->n_bins());
      95             : 
      96   360946383 :   for (auto b : index_range(local_hist))
      97   361775050 :     local_hist[b] = this->local_bin_size(b);
      98             : 
      99             :   // Add all the local histograms to get the global histogram
     100      699733 :   hist = local_hist;
     101      699733 :   this->comm().sum(hist);
     102             : 
     103             :   // All done!
     104      699733 : }
     105             : 
     106             : }
     107             : 
     108             : 
     109             : // Explicitly instantiate for int, double
     110             : template class LIBMESH_EXPORT Parallel::Histogram<int,    unsigned int>;
     111             : template class LIBMESH_EXPORT Parallel::Histogram<double, unsigned int>;
     112             : #ifdef LIBMESH_HAVE_LIBHILBERT
     113             : template class LIBMESH_EXPORT Parallel::Histogram<Parallel::DofObjectKey, unsigned int>;
     114             : #endif
     115             : 
     116             : } // namespace libMesh