Function solve_sparse_through_dense_panels

Eigen/src/SparseCore/SparseSolverBase.h:22–42

  */
template<typename Decomposition, typename Rhs, typename Dest>
typename enable_if<Rhs::ColsAtCompileTime!=1 && Dest::ColsAtCompileTime!=1>::type
solve_sparse_through_dense_panels(const Decomposition &dec, const Rhs& rhs, Dest &dest)
{
  EIGEN_STATIC_ASSERT((Dest::Flags&RowMajorBit)==0,THIS_METHOD_IS_ONLY_FOR_COLUMN_MAJOR_MATRICES);
  typedef typename Dest::Scalar DestScalar;
  // we process the sparse rhs per block of NbColsAtOnce columns temporarily stored into a dense matrix.
  static const Index NbColsAtOnce = 4;
  Index rhsCols = rhs.cols();
  Index size = rhs.rows();
  // the temporary matrices do not need more columns than NbColsAtOnce:
  Index tmpCols = (std::min)(rhsCols, NbColsAtOnce); 
  Eigen::Matrix<DestScalar,Dynamic,Dynamic> tmp(size,tmpCols);
  Eigen::Matrix<DestScalar,Dynamic,Dynamic> tmpX(size,tmpCols);
  for(Index k=0; k<rhsCols; k+=NbColsAtOnce)
  {
    Index actualCols = std::min<Index>(rhsCols-k, NbColsAtOnce);
    tmp.leftCols(actualCols) = rhs.middleCols(k,actualCols);
    tmpX.leftCols(actualCols) = dec.solve(tmp.leftCols(actualCols));
    dest.middleCols(k,actualCols) = tmpX.leftCols(actualCols).sparseView();
  }
}

// Overload for vector as rhs
template<typename Decomposition, typename Rhs, typename Dest>