[136] | 1 | // This file is part of Eigen, a lightweight C++ template library
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| 2 | // for linear algebra.
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| 3 | //
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| 4 | // Copyright (C) 2012 Désiré Nuentsa-Wakam <desire.nuentsa_wakam@inria.fr>
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| 5 | //
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| 6 | // This Source Code Form is subject to the terms of the Mozilla
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| 7 | // Public License v. 2.0. If a copy of the MPL was not distributed
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| 8 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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| 9 |
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| 10 | /*
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| 11 |
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| 12 | * NOTE: This file is the modified version of [s,d,c,z]column_dfs.c file in SuperLU
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| 13 |
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| 14 | * -- SuperLU routine (version 2.0) --
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| 15 | * Univ. of California Berkeley, Xerox Palo Alto Research Center,
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| 16 | * and Lawrence Berkeley National Lab.
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| 17 | * November 15, 1997
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| 18 | *
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| 19 | * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
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| 20 | *
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| 21 | * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
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| 22 | * EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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| 23 | *
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| 24 | * Permission is hereby granted to use or copy this program for any
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| 25 | * purpose, provided the above notices are retained on all copies.
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| 26 | * Permission to modify the code and to distribute modified code is
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| 27 | * granted, provided the above notices are retained, and a notice that
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| 28 | * the code was modified is included with the above copyright notice.
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| 29 | */
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| 30 | #ifndef SPARSELU_COLUMN_DFS_H
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| 31 | #define SPARSELU_COLUMN_DFS_H
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| 32 |
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| 33 | template <typename Scalar, typename Index> class SparseLUImpl;
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| 34 | namespace Eigen {
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| 35 |
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| 36 | namespace internal {
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| 37 |
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| 38 | template<typename IndexVector, typename ScalarVector>
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| 39 | struct column_dfs_traits : no_assignment_operator
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| 40 | {
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| 41 | typedef typename ScalarVector::Scalar Scalar;
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| 42 | typedef typename IndexVector::Scalar Index;
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| 43 | column_dfs_traits(Index jcol, Index& jsuper, typename SparseLUImpl<Scalar, Index>::GlobalLU_t& glu, SparseLUImpl<Scalar, Index>& luImpl)
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| 44 | : m_jcol(jcol), m_jsuper_ref(jsuper), m_glu(glu), m_luImpl(luImpl)
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| 45 | {}
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| 46 | bool update_segrep(Index /*krep*/, Index /*jj*/)
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| 47 | {
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| 48 | return true;
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| 49 | }
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| 50 | void mem_expand(IndexVector& lsub, Index& nextl, Index chmark)
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| 51 | {
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| 52 | if (nextl >= m_glu.nzlmax)
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| 53 | m_luImpl.memXpand(lsub, m_glu.nzlmax, nextl, LSUB, m_glu.num_expansions);
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| 54 | if (chmark != (m_jcol-1)) m_jsuper_ref = emptyIdxLU;
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| 55 | }
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| 56 | enum { ExpandMem = true };
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| 57 |
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| 58 | Index m_jcol;
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| 59 | Index& m_jsuper_ref;
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| 60 | typename SparseLUImpl<Scalar, Index>::GlobalLU_t& m_glu;
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| 61 | SparseLUImpl<Scalar, Index>& m_luImpl;
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| 62 | };
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| 63 |
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| 64 |
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| 65 | /**
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| 66 | * \brief Performs a symbolic factorization on column jcol and decide the supernode boundary
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| 67 | *
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| 68 | * A supernode representative is the last column of a supernode.
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| 69 | * The nonzeros in U[*,j] are segments that end at supernodes representatives.
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| 70 | * The routine returns a list of the supernodal representatives
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| 71 | * in topological order of the dfs that generates them.
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| 72 | * The location of the first nonzero in each supernodal segment
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| 73 | * (supernodal entry location) is also returned.
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| 74 | *
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| 75 | * \param m number of rows in the matrix
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| 76 | * \param jcol Current column
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| 77 | * \param perm_r Row permutation
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| 78 | * \param maxsuper Maximum number of column allowed in a supernode
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| 79 | * \param [in,out] nseg Number of segments in current U[*,j] - new segments appended
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| 80 | * \param lsub_col defines the rhs vector to start the dfs
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| 81 | * \param [in,out] segrep Segment representatives - new segments appended
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| 82 | * \param repfnz First nonzero location in each row
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| 83 | * \param xprune
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| 84 | * \param marker marker[i] == jj, if i was visited during dfs of current column jj;
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| 85 | * \param parent
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| 86 | * \param xplore working array
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| 87 | * \param glu global LU data
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| 88 | * \return 0 success
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| 89 | * > 0 number of bytes allocated when run out of space
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| 90 | *
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| 91 | */
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| 92 | template <typename Scalar, typename Index>
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| 93 | Index SparseLUImpl<Scalar,Index>::column_dfs(const Index m, const Index jcol, IndexVector& perm_r, Index maxsuper, Index& nseg, BlockIndexVector lsub_col, IndexVector& segrep, BlockIndexVector repfnz, IndexVector& xprune, IndexVector& marker, IndexVector& parent, IndexVector& xplore, GlobalLU_t& glu)
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| 94 | {
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| 95 |
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| 96 | Index jsuper = glu.supno(jcol);
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| 97 | Index nextl = glu.xlsub(jcol);
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| 98 | VectorBlock<IndexVector> marker2(marker, 2*m, m);
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| 99 |
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| 100 |
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| 101 | column_dfs_traits<IndexVector, ScalarVector> traits(jcol, jsuper, glu, *this);
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| 102 |
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| 103 | // For each nonzero in A(*,jcol) do dfs
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| 104 | for (Index k = 0; ((k < m) ? lsub_col[k] != emptyIdxLU : false) ; k++)
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| 105 | {
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| 106 | Index krow = lsub_col(k);
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| 107 | lsub_col(k) = emptyIdxLU;
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| 108 | Index kmark = marker2(krow);
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| 109 |
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| 110 | // krow was visited before, go to the next nonz;
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| 111 | if (kmark == jcol) continue;
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| 112 |
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| 113 | dfs_kernel(jcol, perm_r, nseg, glu.lsub, segrep, repfnz, xprune, marker2, parent,
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| 114 | xplore, glu, nextl, krow, traits);
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| 115 | } // for each nonzero ...
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| 116 |
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| 117 | Index fsupc, jptr, jm1ptr, ito, ifrom, istop;
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| 118 | Index nsuper = glu.supno(jcol);
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| 119 | Index jcolp1 = jcol + 1;
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| 120 | Index jcolm1 = jcol - 1;
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| 121 |
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| 122 | // check to see if j belongs in the same supernode as j-1
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| 123 | if ( jcol == 0 )
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| 124 | { // Do nothing for column 0
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| 125 | nsuper = glu.supno(0) = 0 ;
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| 126 | }
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| 127 | else
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| 128 | {
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| 129 | fsupc = glu.xsup(nsuper);
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| 130 | jptr = glu.xlsub(jcol); // Not yet compressed
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| 131 | jm1ptr = glu.xlsub(jcolm1);
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| 132 |
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| 133 | // Use supernodes of type T2 : see SuperLU paper
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| 134 | if ( (nextl-jptr != jptr-jm1ptr-1) ) jsuper = emptyIdxLU;
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| 135 |
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| 136 | // Make sure the number of columns in a supernode doesn't
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| 137 | // exceed threshold
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| 138 | if ( (jcol - fsupc) >= maxsuper) jsuper = emptyIdxLU;
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| 139 |
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| 140 | /* If jcol starts a new supernode, reclaim storage space in
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| 141 | * glu.lsub from previous supernode. Note we only store
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| 142 | * the subscript set of the first and last columns of
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| 143 | * a supernode. (first for num values, last for pruning)
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| 144 | */
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| 145 | if (jsuper == emptyIdxLU)
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| 146 | { // starts a new supernode
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| 147 | if ( (fsupc < jcolm1-1) )
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| 148 | { // >= 3 columns in nsuper
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| 149 | ito = glu.xlsub(fsupc+1);
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| 150 | glu.xlsub(jcolm1) = ito;
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| 151 | istop = ito + jptr - jm1ptr;
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| 152 | xprune(jcolm1) = istop; // intialize xprune(jcol-1)
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| 153 | glu.xlsub(jcol) = istop;
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| 154 |
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| 155 | for (ifrom = jm1ptr; ifrom < nextl; ++ifrom, ++ito)
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| 156 | glu.lsub(ito) = glu.lsub(ifrom);
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| 157 | nextl = ito; // = istop + length(jcol)
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| 158 | }
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| 159 | nsuper++;
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| 160 | glu.supno(jcol) = nsuper;
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| 161 | } // if a new supernode
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| 162 | } // end else: jcol > 0
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| 163 |
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| 164 | // Tidy up the pointers before exit
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| 165 | glu.xsup(nsuper+1) = jcolp1;
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| 166 | glu.supno(jcolp1) = nsuper;
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| 167 | xprune(jcol) = nextl; // Intialize upper bound for pruning
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| 168 | glu.xlsub(jcolp1) = nextl;
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| 169 |
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| 170 | return 0;
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| 171 | }
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| 172 |
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| 173 | } // end namespace internal
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| 174 |
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| 175 | } // end namespace Eigen
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| 176 |
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| 177 | #endif
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