xref: /aosp_15_r20/external/eigen/blas/Rank2Update.h (revision bf2c37156dfe67e5dfebd6d394bad8b2ab5804d4)
1*bf2c3715SXin Li // This file is part of Eigen, a lightweight C++ template library
2*bf2c3715SXin Li // for linear algebra.
3*bf2c3715SXin Li //
4*bf2c3715SXin Li // Copyright (C) 2012 Chen-Pang He <[email protected]>
5*bf2c3715SXin Li //
6*bf2c3715SXin Li // This Source Code Form is subject to the terms of the Mozilla
7*bf2c3715SXin Li // Public License v. 2.0. If a copy of the MPL was not distributed
8*bf2c3715SXin Li // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9*bf2c3715SXin Li 
10*bf2c3715SXin Li #ifndef EIGEN_RANK2UPDATE_H
11*bf2c3715SXin Li #define EIGEN_RANK2UPDATE_H
12*bf2c3715SXin Li 
13*bf2c3715SXin Li namespace internal {
14*bf2c3715SXin Li 
15*bf2c3715SXin Li /* Optimized selfadjoint matrix += alpha * uv' + conj(alpha)*vu'
16*bf2c3715SXin Li  * This is the low-level version of SelfadjointRank2Update.h
17*bf2c3715SXin Li  */
18*bf2c3715SXin Li template<typename Scalar, typename Index, int UpLo>
19*bf2c3715SXin Li struct rank2_update_selector
20*bf2c3715SXin Li {
runrank2_update_selector21*bf2c3715SXin Li   static void run(Index size, Scalar* mat, Index stride, const Scalar* u, const Scalar* v, Scalar alpha)
22*bf2c3715SXin Li   {
23*bf2c3715SXin Li     typedef Map<const Matrix<Scalar,Dynamic,1> > OtherMap;
24*bf2c3715SXin Li     for (Index i=0; i<size; ++i)
25*bf2c3715SXin Li     {
26*bf2c3715SXin Li       Map<Matrix<Scalar,Dynamic,1> >(mat+stride*i+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1)) +=
27*bf2c3715SXin Li       numext::conj(alpha) * numext::conj(u[i]) * OtherMap(v+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1))
28*bf2c3715SXin Li                 + alpha * numext::conj(v[i]) * OtherMap(u+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1));
29*bf2c3715SXin Li     }
30*bf2c3715SXin Li   }
31*bf2c3715SXin Li };
32*bf2c3715SXin Li 
33*bf2c3715SXin Li /* Optimized selfadjoint matrix += alpha * uv' + conj(alpha)*vu'
34*bf2c3715SXin Li  * The matrix is in packed form.
35*bf2c3715SXin Li  */
36*bf2c3715SXin Li template<typename Scalar, typename Index, int UpLo>
37*bf2c3715SXin Li struct packed_rank2_update_selector
38*bf2c3715SXin Li {
runpacked_rank2_update_selector39*bf2c3715SXin Li   static void run(Index size, Scalar* mat, const Scalar* u, const Scalar* v, Scalar alpha)
40*bf2c3715SXin Li   {
41*bf2c3715SXin Li     typedef Map<const Matrix<Scalar,Dynamic,1> > OtherMap;
42*bf2c3715SXin Li     Index offset = 0;
43*bf2c3715SXin Li     for (Index i=0; i<size; ++i)
44*bf2c3715SXin Li     {
45*bf2c3715SXin Li       Map<Matrix<Scalar,Dynamic,1> >(mat+offset, UpLo==Lower ? size-i : (i+1)) +=
46*bf2c3715SXin Li       numext::conj(alpha) * numext::conj(u[i]) * OtherMap(v+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1))
47*bf2c3715SXin Li                 + alpha * numext::conj(v[i]) * OtherMap(u+(UpLo==Lower ? i : 0), UpLo==Lower ? size-i : (i+1));
48*bf2c3715SXin Li       //FIXME This should be handled outside.
49*bf2c3715SXin Li       mat[offset+(UpLo==Lower ? 0 : i)] = numext::real(mat[offset+(UpLo==Lower ? 0 : i)]);
50*bf2c3715SXin Li       offset += UpLo==Lower ? size-i : (i+1);
51*bf2c3715SXin Li     }
52*bf2c3715SXin Li   }
53*bf2c3715SXin Li };
54*bf2c3715SXin Li 
55*bf2c3715SXin Li } // end namespace internal
56*bf2c3715SXin Li 
57*bf2c3715SXin Li #endif // EIGEN_RANK2UPDATE_H
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