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
14 namespace Eigen {
15 namespace internal {
16
17 /**
18 * \brief Count Nonzero elements in the factors
19 */
20 template <typename Scalar, typename Index>
countnz(const Index n,Index & nnzL,Index & nnzU,GlobalLU_t & glu)21 void 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 */
51 template <typename Scalar, typename Index>
fixupL(const Index n,const IndexVector & perm_r,GlobalLU_t & glu)52 void 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