93 lines
3.1 KiB
C++
93 lines
3.1 KiB
C++
// Copyright (C) 2024-2025 Yixuan Qiu <yixuan.qiu@cos.name>
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla
|
|
// Public License v. 2.0. If a copy of the MPL was not distributed
|
|
// with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
|
|
|
|
#ifndef SPECTRA_DENSE_HERM_MAT_PROD_H
|
|
#define SPECTRA_DENSE_HERM_MAT_PROD_H
|
|
|
|
#include <Eigen/Core>
|
|
|
|
namespace Spectra {
|
|
|
|
///
|
|
/// \ingroup MatOp
|
|
///
|
|
/// This class defines the matrix-vector multiplication operation on a
|
|
/// Hermitian complex matrix \f$A\f$, i.e., calculating \f$y=Ax\f$ for any vector
|
|
/// \f$x\f$. It is mainly used in the HermEigsSolver eigen solver.
|
|
///
|
|
/// \tparam Scalar_ The element type of the matrix, for example,
|
|
/// `std::complex<float>`, `std::complex<double>`,
|
|
/// and `std::complex<long double>`.
|
|
/// \tparam Uplo Either `Eigen::Lower` or `Eigen::Upper`, indicating which
|
|
/// triangular part of the matrix is used.
|
|
/// \tparam Flags Either `Eigen::ColMajor` or `Eigen::RowMajor`, indicating
|
|
/// the storage format of the input matrix.
|
|
///
|
|
template <typename Scalar_, int Uplo = Eigen::Lower, int Flags = Eigen::ColMajor>
|
|
class DenseHermMatProd
|
|
{
|
|
public:
|
|
///
|
|
/// Element type of the matrix.
|
|
///
|
|
using Scalar = Scalar_;
|
|
|
|
private:
|
|
using Index = Eigen::Index;
|
|
using Matrix = Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic, Flags>;
|
|
using Vector = Eigen::Matrix<Scalar, Eigen::Dynamic, 1>;
|
|
using MapConstVec = Eigen::Map<const Vector>;
|
|
using MapVec = Eigen::Map<Vector>;
|
|
using ConstGenericMatrix = const Eigen::Ref<const Matrix>;
|
|
|
|
ConstGenericMatrix m_mat;
|
|
|
|
public:
|
|
///
|
|
/// Constructor to create the matrix operation object.
|
|
///
|
|
/// \param mat An **Eigen** matrix object, whose type can be
|
|
/// `Eigen::Matrix<Scalar, ...>` (e.g. `Eigen::MatrixXcd` and
|
|
/// `Eigen::MatrixXcf`), or its mapped version
|
|
/// (e.g. `Eigen::Map<Eigen::MatrixXcd>`).
|
|
///
|
|
template <typename Derived>
|
|
DenseHermMatProd(const Eigen::MatrixBase<Derived>& mat) :
|
|
m_mat(mat)
|
|
{
|
|
static_assert(
|
|
static_cast<int>(Derived::PlainObject::IsRowMajor) == static_cast<int>(Matrix::IsRowMajor),
|
|
"DenseHermMatProd: the \"Flags\" template parameter does not match the input matrix (Eigen::ColMajor/Eigen::RowMajor)");
|
|
}
|
|
|
|
///
|
|
/// Return the number of rows of the underlying matrix.
|
|
///
|
|
Index rows() const { return m_mat.rows(); }
|
|
///
|
|
/// Return the number of columns of the underlying matrix.
|
|
///
|
|
Index cols() const { return m_mat.cols(); }
|
|
|
|
///
|
|
/// Perform the matrix-vector multiplication operation \f$y=Ax\f$.
|
|
///
|
|
/// \param x_in Pointer to the \f$x\f$ vector.
|
|
/// \param y_out Pointer to the \f$y\f$ vector.
|
|
///
|
|
// y_out = A * x_in
|
|
void perform_op(const Scalar* x_in, Scalar* y_out) const
|
|
{
|
|
MapConstVec x(x_in, m_mat.cols());
|
|
MapVec y(y_out, m_mat.rows());
|
|
y.noalias() = m_mat.template selfadjointView<Uplo>() * x;
|
|
}
|
|
};
|
|
|
|
} // namespace Spectra
|
|
|
|
#endif // SPECTRA_DENSE_HERM_MAT_PROD_H
|