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             : #include "libmesh/coupling_matrix.h"
      20             : 
      21             : 
      22             : namespace libMesh {
      23             : 
      24           0 : CouplingMatrix & CouplingMatrix::operator&= (const CouplingMatrix & other)
      25             : {
      26           0 :   const std::size_t max_size = std::numeric_limits<std::size_t>::max();
      27             : 
      28           0 :   rc_type::iterator start_range = this->_ranges.begin();
      29             : 
      30           0 :   rc_type::const_iterator     other_range = other._ranges.begin();
      31           0 :   const rc_type::const_iterator other_end = other._ranges.end();
      32             : 
      33           0 :   for (; other_range != other_end; ++other_range)
      34             :     {
      35           0 :       std::size_t other_range_start = other_range->first;
      36           0 :       std::size_t other_range_end = other_range->second;
      37             : 
      38             :       // Find our range that might contain the start of the other
      39             :       // range.
      40             :       // lower_bound isn't *quite* what we want.
      41             :       // Because the other._ranges is sorted, we can contract this
      42             :       // search as we proceed, beginning with lb rather than at
      43             :       // begin() every time.
      44             :       rc_type::iterator lb =
      45           0 :         std::upper_bound (start_range, this->_ranges.end(),
      46           0 :                           std::make_pair(other_range_start, max_size));
      47           0 :       if (lb!=start_range)
      48           0 :         --lb;
      49             :       else
      50           0 :         lb=this->_ranges.end();
      51             : 
      52           0 :       start_range = lb;
      53             : 
      54             :       // If no range might contain the start of the new range then
      55             :       // we can just break out of here and start appending any
      56             :       // remaining ranges.
      57           0 :       if (lb == this->_ranges.end())
      58           0 :         break;
      59             : 
      60             :       // We did find a range which might contain the start of the new
      61             :       // range.
      62           0 :       const std::size_t lastloc  = lb->second;
      63           0 :       libmesh_assert_less_equal(lb->first, lastloc);
      64           0 :       libmesh_assert_less_equal(lb->first, other_range_start);
      65             : 
      66             : #ifdef DEBUG
      67             :       {
      68           0 :         CouplingMatrix::rc_type::const_iterator next = lb;
      69           0 :         next++;
      70           0 :         if (next != this->_ranges.end())
      71             :           {
      72             :             // Ranges should be sorted and should not touch
      73           0 :             libmesh_assert_greater(next->first, lastloc+1);
      74             :           }
      75             :       }
      76             : #endif
      77             : 
      78           0 :       CouplingMatrix::rc_type::iterator next = lb;
      79           0 :       next++;
      80             : 
      81             :       // We might need to extend this range or add a new range.
      82             :       // Merge contiguous ranges
      83           0 :       if (other_range_start <= lastloc)
      84           0 :         lb->second = other_range_end;
      85             :       // Or insert a new range.  This invalidates existing iterators,
      86             :       // but that's okay; the only iterator we need is for the newly
      87             :       // inserted range.
      88             :       else
      89           0 :         start_range = lb = this->_ranges.emplace
      90           0 :           (next, other_range_start, other_range_end);
      91             : 
      92             :       // At this point we have a range lb that may potentially overlap
      93             :       // subsequent existing ranges, in which case we need to merge
      94             :       // some.
      95             : 
      96             :       // First expand our range as necessary while finding ranges
      97             :       // which will be redundant later
      98           0 :       for (const std::size_t nextloc =
      99           0 :              (next == this->_ranges.end()) ?
     100           0 :              std::numeric_limits<std::size_t>::max() : next->first;
     101           0 :            nextloc <= lb->second; ++next)
     102             :         {
     103             :           // Ranges should be sorted and should not have been touching
     104             :           // initially
     105           0 :           libmesh_assert_greater(nextloc, lastloc+1);
     106             : 
     107           0 :           lb->second = std::max(lb->second, next->second);
     108             :         }
     109             : 
     110           0 :       CouplingMatrix::rc_type::iterator oldnext = lb;
     111           0 :       oldnext++;
     112             : 
     113             :       // Finally remove the redundant ranges
     114           0 :       this->_ranges.erase(oldnext, next);
     115             :     }
     116             : 
     117             :   // If we broke out early but we still have more other_ranges then
     118             :   // we can safely just append them to our ranges.
     119           0 :   for (; other_range != other_end; ++other_range)
     120           0 :     this->_ranges.push_back(*other_range);
     121             : 
     122             :   // Behave like a standard modification operator
     123           0 :   return *this;
     124             : }
     125             : 
     126             : }