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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 StorageIndex>
countnz(const Index n,Index & nnzL,Index & nnzU,GlobalLU_t & glu)21 void SparseLUImpl<Scalar,StorageIndex>::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 StorageIndex>
fixupL(const Index n,const IndexVector & perm_r,GlobalLU_t & glu)52 void SparseLUImpl<Scalar,StorageIndex>::fixupL(const Index n, const IndexVector& perm_r, GlobalLU_t& glu)
53 {
54   Index fsupc, i, j, k, jstart;
55 
56   StorageIndex 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