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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Chen-Pang He <jdh8@ms63.hinet.net>
//
// 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_PACKED_TRIANGULAR_SOLVER_VECTOR_H
#define EIGEN_PACKED_TRIANGULAR_SOLVER_VECTOR_H
namespace internal {
template <typename LhsScalar, typename RhsScalar, typename Index, int Side, int Mode, bool Conjugate, int StorageOrder>
struct packed_triangular_solve_vector;
// forward and backward substitution, row-major, rhs is a vector
template <typename LhsScalar, typename RhsScalar, typename Index, int Mode, bool Conjugate>
struct packed_triangular_solve_vector<LhsScalar, RhsScalar, Index, OnTheLeft, Mode, Conjugate, RowMajor> {
enum { IsLower = (Mode & Lower) == Lower };
static void run(Index size, const LhsScalar* lhs, RhsScalar* rhs) {
internal::conj_if<Conjugate> cj;
typedef Map<const Matrix<LhsScalar, Dynamic, 1> > LhsMap;
typedef typename conj_expr_if<Conjugate, LhsMap>::type ConjLhsType;
lhs += IsLower ? 0 : (size * (size + 1) >> 1) - 1;
for (Index pi = 0; pi < size; ++pi) {
Index i = IsLower ? pi : size - pi - 1;
Index s = IsLower ? 0 : 1;
if (pi > 0)
rhs[i] -= (ConjLhsType(LhsMap(lhs + s, pi))
.cwiseProduct(Map<const Matrix<RhsScalar, Dynamic, 1> >(rhs + (IsLower ? 0 : i + 1), pi)))
.sum();
if (!(Mode & UnitDiag)) rhs[i] /= cj(lhs[IsLower ? i : 0]);
IsLower ? lhs += pi + 1 : lhs -= pi + 2;
}
}
};
// forward and backward substitution, column-major, rhs is a vector
template <typename LhsScalar, typename RhsScalar, typename Index, int Mode, bool Conjugate>
struct packed_triangular_solve_vector<LhsScalar, RhsScalar, Index, OnTheLeft, Mode, Conjugate, ColMajor> {
enum { IsLower = (Mode & Lower) == Lower };
static void run(Index size, const LhsScalar* lhs, RhsScalar* rhs) {
internal::conj_if<Conjugate> cj;
typedef Map<const Matrix<LhsScalar, Dynamic, 1> > LhsMap;
typedef typename conj_expr_if<Conjugate, LhsMap>::type ConjLhsType;
lhs += IsLower ? 0 : size * (size - 1) >> 1;
for (Index pi = 0; pi < size; ++pi) {
Index i = IsLower ? pi : size - pi - 1;
Index r = size - pi - 1;
if (!(Mode & UnitDiag)) rhs[i] /= cj(lhs[IsLower ? 0 : i]);
if (r > 0)
Map<Matrix<RhsScalar, Dynamic, 1> >(rhs + (IsLower ? i + 1 : 0), r) -=
rhs[i] * ConjLhsType(LhsMap(lhs + (IsLower ? 1 : 0), r));
IsLower ? lhs += size - pi : lhs -= r;
}
}
};
template <typename LhsScalar, typename RhsScalar, typename Index, int Mode, bool Conjugate, int StorageOrder>
struct packed_triangular_solve_vector<LhsScalar, RhsScalar, Index, OnTheRight, Mode, Conjugate, StorageOrder> {
static void run(Index size, const LhsScalar* lhs, RhsScalar* rhs) {
packed_triangular_solve_vector<LhsScalar, RhsScalar, Index, OnTheLeft,
((Mode & Upper) == Upper ? Lower : Upper) | (Mode & UnitDiag), Conjugate,
StorageOrder == RowMajor ? ColMajor : RowMajor>::run(size, lhs, rhs);
}
};
} // end namespace internal
#endif // EIGEN_PACKED_TRIANGULAR_SOLVER_VECTOR_H