Eigen::COLAMDOrdering< StorageIndex > Class Template Reference

#include <Ordering.h>

Public Types
typedef PermutationMatrix< Dynamic, Dynamic, StorageIndex >	PermutationType
typedef Matrix< StorageIndex, Dynamic, 1 >	IndexVector

Public Member Functions
template<typename MatrixType >
void	operator() (const MatrixType &mat, PermutationType &perm)

Detailed Description

template<typename StorageIndex>
class Eigen::COLAMDOrdering< StorageIndex >

Template Parameters

StorageIndex

The type of indices of the matrix

Functor computing the column approximate minimum degree ordering The matrix should be in column-major and compressed format (see SparseMatrix::makeCompressed()).

Member Typedef Documentation

IndexVector

template<typename StorageIndex >

typedef Matrix<StorageIndex, Dynamic, 1> Eigen::COLAMDOrdering< StorageIndex >::IndexVector

PermutationType

template<typename StorageIndex >

typedef PermutationMatrix<Dynamic, Dynamic, StorageIndex> Eigen::COLAMDOrdering< StorageIndex >::PermutationType

Member Function Documentation

operator()()

template<typename StorageIndex >

template<typename MatrixType >

void Eigen::COLAMDOrdering< StorageIndex >::operator() ( const MatrixType &  mat, PermutationType &  perm  )

inline

Compute the permutation vector perm form the sparse matrix mat

Warning

The input sparse matrix mat must be in compressed mode (see SparseMatrix::makeCompressed()).

                                                                {
    eigen_assert(mat.isCompressed() &&
                 "COLAMDOrdering requires a sparse matrix in compressed mode. Call .makeCompressed() before passing it "
                 "to COLAMDOrdering");
 
    StorageIndex m = StorageIndex(mat.rows());
    StorageIndex n = StorageIndex(mat.cols());
    StorageIndex nnz = StorageIndex(mat.nonZeros());
    // Get the recommended value of Alen to be used by colamd
    StorageIndex Alen = internal::Colamd::recommended(nnz, m, n);
    // Set the default parameters
    double knobs[internal::Colamd::NKnobs];
    StorageIndex stats[internal::Colamd::NStats];
    internal::Colamd::set_defaults(knobs);
 
    IndexVector p(n + 1), A(Alen);
    for (StorageIndex i = 0; i <= n; i++) p(i) = mat.outerIndexPtr()[i];
    for (StorageIndex i = 0; i < nnz; i++) A(i) = mat.innerIndexPtr()[i];
    // Call Colamd routine to compute the ordering
    StorageIndex info = internal::Colamd::compute_ordering(m, n, Alen, A.data(), p.data(), knobs, stats);
    EIGEN_UNUSED_VARIABLE(info);
    eigen_assert(info && "COLAMD failed ");
 
    perm.resize(n);
    for (StorageIndex i = 0; i < n; i++) perm.indices()(p(i)) = i;
  }

References Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::cols(), internal::Colamd::compute_ordering(), Eigen::PlainObjectBase< Derived >::data(), eigen_assert, EIGEN_UNUSED_VARIABLE, i, Eigen::PermutationMatrix< SizeAtCompileTime, MaxSizeAtCompileTime, StorageIndex_ >::indices(), info, Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::innerIndexPtr(), Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::isCompressed(), m, n, internal::Colamd::NKnobs, Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::nonZeros(), internal::Colamd::NStats, Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::outerIndexPtr(), p, internal::Colamd::recommended(), Eigen::PermutationBase< Derived >::resize(), Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::rows(), and internal::Colamd::set_defaults().

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The documentation for this class was generated from the following file:

• Ordering.h