Function analyseMatrixSparsity

highs/util/HighsUtils.cpp:561–697

}

void analyseMatrixSparsity(const HighsLogOptions& log_options,
                           const char* message, HighsInt numCol,
                           HighsInt numRow, const std::vector<HighsInt>& Astart,
                           const std::vector<HighsInt>& Aindex) {
  if (numCol == 0) return;
  std::vector<HighsInt> rowCount;
  std::vector<HighsInt> colCount;

  rowCount.assign(numRow, 0);
  colCount.resize(numCol);

  for (HighsInt col = 0; col < numCol; col++) {
    colCount[col] = Astart[col + 1] - Astart[col];
    for (HighsInt el = Astart[col]; el < Astart[col + 1]; el++)
      rowCount[Aindex[el]]++;
  }
  analyseVectorValues(&log_options, "Column counts", numCol, colCount);
  analyseVectorValues(&log_options, "Row counts", numRow, rowCount);

  const HighsInt maxCat = 10;
  std::vector<HighsInt> CatV;
  std::vector<HighsInt> rowCatK;
  std::vector<HighsInt> colCatK;
  CatV.resize(maxCat + 1);
  rowCatK.assign(maxCat + 1, 0);
  colCatK.assign(maxCat + 1, 0);

  CatV[1] = 1;
  for (HighsInt cat = 2; cat < maxCat + 1; cat++) {
    CatV[cat] = 2 * CatV[cat - 1];
  }

  HighsInt maxRowCount = 0;
  HighsInt maxColCount = 0;
  for (HighsInt col = 0; col < numCol; col++) {
    maxColCount = std::max(colCount[col], maxColCount);
    HighsInt fdCat = maxCat;
    for (HighsInt cat = 0; cat < maxCat - 1; cat++) {
      if (colCount[col] < CatV[cat + 1]) {
        fdCat = cat;
        break;
      }
    }
    colCatK[fdCat]++;
  }

  for (HighsInt row = 0; row < numRow; row++) {
    maxRowCount = std::max(rowCount[row], maxRowCount);
    HighsInt fdCat = maxCat;
    for (HighsInt cat = 0; cat < maxCat - 1; cat++) {
      if (rowCount[row] < CatV[cat + 1]) {
        fdCat = cat;
        break;
      }
    }
    rowCatK[fdCat]++;
  }