1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
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
11#ifndef EIGEN_SPARSELU_UTILS_H
12#define EIGEN_SPARSELU_UTILS_H
13
14namespace Eigen {
15namespace internal {
16
17/**
18 * \brief Count Nonzero elements in the factors
19 */
20template <typename Scalar, typename Index>
21void SparseLUImpl<Scalar,Index>::countnz(const Index n, Index& nnzL, Index& nnzU, GlobalLU_t& glu)
22{
23 nnzL = 0;
24 nnzU = (glu.xusub)(n);
25 Index nsuper = (glu.supno)(n);
26 Index jlen;
27 Index i, j, fsupc;
28 if (n <= 0 ) return;
29 // For each supernode
30 for (i = 0; i <= nsuper; i++)
31 {
32   fsupc = glu.xsup(i);
33   jlen = glu.xlsub(fsupc+1) - glu.xlsub(fsupc);
34
35   for (j = fsupc; j < glu.xsup(i+1); j++)
36   {
37     nnzL += jlen;
38     nnzU += j - fsupc + 1;
39     jlen--;
40   }
41 }
42}
43
44/**
45 * \brief Fix up the data storage lsub for L-subscripts.
46 *
47 * It removes the subscripts sets for structural pruning,
48 * and applies permutation to the remaining subscripts
49 *
50 */
51template <typename Scalar, typename Index>
52void SparseLUImpl<Scalar,Index>::fixupL(const Index n, const IndexVector& perm_r, GlobalLU_t& glu)
53{
54  Index fsupc, i, j, k, jstart;
55
56  Index nextl = 0;
57  Index nsuper = (glu.supno)(n);
58
59  // For each supernode
60  for (i = 0; i <= nsuper; i++)
61  {
62    fsupc = glu.xsup(i);
63    jstart = glu.xlsub(fsupc);
64    glu.xlsub(fsupc) = nextl;
65    for (j = jstart; j < glu.xlsub(fsupc + 1); j++)
66    {
67      glu.lsub(nextl) = perm_r(glu.lsub(j)); // Now indexed into P*A
68      nextl++;
69    }
70    for (k = fsupc+1; k < glu.xsup(i+1); k++)
71      glu.xlsub(k) = nextl; // other columns in supernode i
72  }
73
74  glu.xlsub(n) = nextl;
75}
76
77} // end namespace internal
78
79} // end namespace Eigen
80#endif // EIGEN_SPARSELU_UTILS_H
81