mirror of
https://gitlab.com/libeigen/eigen.git
synced 2025-03-01 18:26:24 +08:00
58 lines
1.7 KiB
C++
58 lines
1.7 KiB
C++
// 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_RANK2UPDATE_H
|
|
#define EIGEN_RANK2UPDATE_H
|
|
|
|
namespace internal {
|
|
|
|
/* Optimized selfadjoint matrix += alpha * uv' + conj(alpha)*vu'
|
|
* This is the low-level version of SelfadjointRank2Update.h
|
|
*/
|
|
template<typename Scalar, typename Index, int UpLo>
|
|
struct rank2_update_selector;
|
|
|
|
template<typename Scalar, typename Index>
|
|
struct rank2_update_selector<Scalar,Index,Upper>
|
|
{
|
|
static void run(Index size, Scalar* mat, Index stride, const Scalar* _u, const Scalar* _v, Scalar alpha)
|
|
{
|
|
typedef Matrix<Scalar,Dynamic,1> PlainVector;
|
|
Map<const PlainVector> u(_u, size), v(_v, size);
|
|
|
|
for (Index i=0; i<size; ++i)
|
|
{
|
|
Map<PlainVector>(mat+stride*i, i+1) +=
|
|
conj(alpha) * conj(_u[i]) * v.head(i+1)
|
|
+ alpha * conj(_v[i]) * u.head(i+1);
|
|
}
|
|
}
|
|
};
|
|
|
|
template<typename Scalar, typename Index>
|
|
struct rank2_update_selector<Scalar,Index,Lower>
|
|
{
|
|
static void run(Index size, Scalar* mat, Index stride, const Scalar* _u, const Scalar* _v, Scalar alpha)
|
|
{
|
|
typedef Matrix<Scalar,Dynamic,1> PlainVector;
|
|
Map<const PlainVector> u(_u, size), v(_v, size);
|
|
|
|
for (Index i=0; i<size; ++i)
|
|
{
|
|
Map<PlainVector>(mat+(stride+1)*i, size-i) +=
|
|
conj(alpha) * conj(_u[i]) * v.tail(size-i)
|
|
+ alpha * conj(_v[i]) * u.tail(size-i);
|
|
}
|
|
}
|
|
};
|
|
|
|
} // end namespace internal
|
|
|
|
#endif // EIGEN_RANK2UPDATE_H
|