1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2012 Chen-Pang He <jdh8@ms63.hinet.net>
5//
6// This Source Code Form is subject to the terms of the Mozilla
7// Public License v. 2.0. If a copy of the MPL was not distributed
8// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10#ifndef EIGEN_RANK2UPDATE_H
11#define EIGEN_RANK2UPDATE_H
12
13namespace internal {
14
15/* Optimized selfadjoint matrix += alpha * uv' + conj(alpha)*vu'
16 * This is the low-level version of SelfadjointRank2Update.h
17 */
18template<typename Scalar, typename Index, int UpLo>
19struct rank2_update_selector
20{
21  static void run(Index size, Scalar* mat, Index stride, const Scalar* u, const Scalar* v, Scalar alpha)
22  {
23    typedef Map<const Matrix<Scalar,Dynamic,1> > OtherMap;
24    for (Index i=0; i<size; ++i)
25    {
26      Map<Matrix<Scalar,Dynamic,1> >(mat+stride*i+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1)) +=
27      numext::conj(alpha) * numext::conj(u[i]) * OtherMap(v+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1))
28                + alpha * numext::conj(v[i]) * OtherMap(u+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1));
29    }
30  }
31};
32
33/* Optimized selfadjoint matrix += alpha * uv' + conj(alpha)*vu'
34 * The matrix is in packed form.
35 */
36template<typename Scalar, typename Index, int UpLo>
37struct packed_rank2_update_selector
38{
39  static void run(Index size, Scalar* mat, const Scalar* u, const Scalar* v, Scalar alpha)
40  {
41    typedef Map<const Matrix<Scalar,Dynamic,1> > OtherMap;
42    Index offset = 0;
43    for (Index i=0; i<size; ++i)
44    {
45      Map<Matrix<Scalar,Dynamic,1> >(mat+offset, UpLo==Lower ? size-i : (i+1)) +=
46      numext::conj(alpha) * numext::conj(u[i]) * OtherMap(v+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1))
47                + alpha * numext::conj(v[i]) * OtherMap(u+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1));
48      //FIXME This should be handled outside.
49      mat[offset+(UpLo==Lower ? 0 : i)] = numext::real(mat[offset+(UpLo==Lower ? 0 : i)]);
50      offset += UpLo==Lower ? size-i : (i+1);
51    }
52  }
53};
54
55} // end namespace internal
56
57#endif // EIGEN_RANK2UPDATE_H
58