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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_SPARSELU_UTILS_H
#define EIGEN_SPARSELU_UTILS_H
// IWYU pragma: private
#include "./InternalHeaderCheck.h"
namespace Eigen {
namespace internal {
/**
* \brief Count Nonzero elements in the factors
*/
template <typename Scalar, typename StorageIndex>
void SparseLUImpl<Scalar, StorageIndex>::countnz(const Index n, Index& nnzL, Index& nnzU, GlobalLU_t& glu) {
nnzL = 0;
nnzU = (glu.xusub)(n);
Index nsuper = (glu.supno)(n);
Index jlen;
Index i, j, fsupc;
if (n <= 0) return;
// For each supernode
for (i = 0; i <= nsuper; i++) {
fsupc = glu.xsup(i);
jlen = glu.xlsub(fsupc + 1) - glu.xlsub(fsupc);
for (j = fsupc; j < glu.xsup(i + 1); j++) {
nnzL += jlen;
nnzU += j - fsupc + 1;
jlen--;
}
}
}
/**
* \brief Fix up the data storage lsub for L-subscripts.
*
* It removes the subscripts sets for structural pruning,
* and applies permutation to the remaining subscripts
*
*/
template <typename Scalar, typename StorageIndex>
void SparseLUImpl<Scalar, StorageIndex>::fixupL(const Index n, const IndexVector& perm_r, GlobalLU_t& glu) {
Index fsupc, i, j, k, jstart;
StorageIndex nextl = 0;
Index nsuper = (glu.supno)(n);
// For each supernode
for (i = 0; i <= nsuper; i++) {
fsupc = glu.xsup(i);
jstart = glu.xlsub(fsupc);
glu.xlsub(fsupc) = nextl;
for (j = jstart; j < glu.xlsub(fsupc + 1); j++) {
glu.lsub(nextl) = perm_r(glu.lsub(j)); // Now indexed into P*A
nextl++;
}
for (k = fsupc + 1; k < glu.xsup(i + 1); k++) glu.xlsub(k) = nextl; // other columns in supernode i
}
glu.xlsub(n) = nextl;
}
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_SPARSELU_UTILS_H