mirror of
https://gitlab.com/libeigen/eigen.git
synced 2024-12-27 07:29:52 +08:00
98 lines
3.5 KiB
C++
98 lines
3.5 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
|
|
// for linear algebra.
|
|
//
|
|
// Copyright (C) 2011 Gael Guennebaud <gael.guennebaud@inria.fr>
|
|
//
|
|
// 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 http://mozilla.org/MPL/2.0/.
|
|
|
|
#ifndef EIGEN_BAND_TRIANGULARSOLVER_H
|
|
#define EIGEN_BAND_TRIANGULARSOLVER_H
|
|
|
|
namespace internal {
|
|
|
|
/* \internal
|
|
* Solve Ax=b with A a band triangular matrix
|
|
* TODO: extend it to matrices for x abd b */
|
|
template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar, int StorageOrder>
|
|
struct band_solve_triangular_selector;
|
|
|
|
|
|
template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar>
|
|
struct band_solve_triangular_selector<Index,Mode,LhsScalar,ConjLhs,RhsScalar,RowMajor>
|
|
{
|
|
typedef Map<const Matrix<LhsScalar,Dynamic,Dynamic,RowMajor>, 0, OuterStride<> > LhsMap;
|
|
typedef Map<Matrix<RhsScalar,Dynamic,1> > RhsMap;
|
|
enum { IsLower = (Mode&Lower) ? 1 : 0 };
|
|
static void run(Index size, Index k, const LhsScalar* _lhs, Index lhsStride, RhsScalar* _other)
|
|
{
|
|
const LhsMap lhs(_lhs,size,k+1,OuterStride<>(lhsStride));
|
|
RhsMap other(_other,size,1);
|
|
typename internal::conditional<
|
|
ConjLhs,
|
|
const CwiseUnaryOp<typename internal::scalar_conjugate_op<LhsScalar>,LhsMap>,
|
|
const LhsMap&>
|
|
::type cjLhs(lhs);
|
|
|
|
for(int col=0 ; col<other.cols() ; ++col)
|
|
{
|
|
for(int ii=0; ii<size; ++ii)
|
|
{
|
|
int i = IsLower ? ii : size-ii-1;
|
|
int actual_k = (std::min)(k,ii);
|
|
int actual_start = IsLower ? k-actual_k : 1;
|
|
|
|
if(actual_k>0)
|
|
other.coeffRef(i,col) -= cjLhs.row(i).segment(actual_start,actual_k).transpose()
|
|
.cwiseProduct(other.col(col).segment(IsLower ? i-actual_k : i+1,actual_k)).sum();
|
|
|
|
if((Mode&UnitDiag)==0)
|
|
other.coeffRef(i,col) /= cjLhs(i,IsLower ? k : 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
};
|
|
|
|
template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar>
|
|
struct band_solve_triangular_selector<Index,Mode,LhsScalar,ConjLhs,RhsScalar,ColMajor>
|
|
{
|
|
typedef Map<const Matrix<LhsScalar,Dynamic,Dynamic,ColMajor>, 0, OuterStride<> > LhsMap;
|
|
typedef Map<Matrix<RhsScalar,Dynamic,1> > RhsMap;
|
|
enum { IsLower = (Mode&Lower) ? 1 : 0 };
|
|
static void run(Index size, Index k, const LhsScalar* _lhs, Index lhsStride, RhsScalar* _other)
|
|
{
|
|
const LhsMap lhs(_lhs,k+1,size,OuterStride<>(lhsStride));
|
|
RhsMap other(_other,size,1);
|
|
typename internal::conditional<
|
|
ConjLhs,
|
|
const CwiseUnaryOp<typename internal::scalar_conjugate_op<LhsScalar>,LhsMap>,
|
|
const LhsMap&>
|
|
::type cjLhs(lhs);
|
|
|
|
for(int col=0 ; col<other.cols() ; ++col)
|
|
{
|
|
for(int ii=0; ii<size; ++ii)
|
|
{
|
|
int i = IsLower ? ii : size-ii-1;
|
|
int actual_k = (std::min)(k,size-ii-1);
|
|
int actual_start = IsLower ? 1 : k-actual_k;
|
|
|
|
if((Mode&UnitDiag)==0)
|
|
other.coeffRef(i,col) /= cjLhs(IsLower ? 0 : k, i);
|
|
|
|
if(actual_k>0)
|
|
other.col(col).segment(IsLower ? i+1 : i-actual_k, actual_k)
|
|
-= other.coeff(i,col) * cjLhs.col(i).segment(actual_start,actual_k);
|
|
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
|
|
} // end namespace internal
|
|
|
|
#endif // EIGEN_BAND_TRIANGULARSOLVER_H
|