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include/Eigen/src/SparseLU/SparseLU_copy_to_ucol.h

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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/.
+/*
+
+ * NOTE: This file is the modified version of [s,d,c,z]copy_to_ucol.c file in SuperLU
+
+ * -- SuperLU routine (version 2.0) --
+ * Univ. of California Berkeley, Xerox Palo Alto Research Center,
+ * and Lawrence Berkeley National Lab.
+ * November 15, 1997
+ *
+ * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
+ * EXPRESSED OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program for any
+ * purpose, provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is
+ * granted, provided the above notices are retained, and a notice that
+ * the code was modified is included with the above copyright notice.
+ */
+#ifndef SPARSELU_COPY_TO_UCOL_H
+#define SPARSELU_COPY_TO_UCOL_H
+
+// IWYU pragma: private
+#include "./InternalHeaderCheck.h"
+
+namespace Eigen {
+namespace internal {
+
+/**
+ * \brief Performs numeric block updates (sup-col) in topological order
+ *
+ * \param jcol current column to update
+ * \param nseg Number of segments in the U part
+ * \param segrep segment representative ...
+ * \param repfnz First nonzero column in each row  ...
+ * \param perm_r Row permutation
+ * \param dense Store the full representation of the column
+ * \param glu Global LU data.
+ * \return 0 - successful return
+ *         > 0 - number of bytes allocated when run out of space
+ *
+ */
+template <typename Scalar, typename StorageIndex>
+Index SparseLUImpl<Scalar, StorageIndex>::copy_to_ucol(const Index jcol, const Index nseg, IndexVector& segrep,
+                                                       BlockIndexVector repfnz, IndexVector& perm_r,
+                                                       BlockScalarVector dense, GlobalLU_t& glu) {
+  Index ksub, krep, ksupno;
+
+  Index jsupno = glu.supno(jcol);
+
+  // For each nonzero supernode segment of U[*,j] in topological order
+  Index k = nseg - 1, i;
+  StorageIndex nextu = glu.xusub(jcol);
+  Index kfnz, isub, segsize;
+  Index new_next, irow;
+  Index fsupc, mem;
+  for (ksub = 0; ksub < nseg; ksub++) {
+    krep = segrep(k);
+    k--;
+    ksupno = glu.supno(krep);
+    if (jsupno != ksupno)  // should go into ucol();
+    {
+      kfnz = repfnz(krep);
+      if (kfnz != emptyIdxLU) {  // Nonzero U-segment
+        fsupc = glu.xsup(ksupno);
+        isub = glu.xlsub(fsupc) + kfnz - fsupc;
+        segsize = krep - kfnz + 1;
+        new_next = nextu + segsize;
+        while (new_next > glu.nzumax) {
+          mem = memXpand<ScalarVector>(glu.ucol, glu.nzumax, nextu, UCOL, glu.num_expansions);
+          if (mem) return mem;
+          mem = memXpand<IndexVector>(glu.usub, glu.nzumax, nextu, USUB, glu.num_expansions);
+          if (mem) return mem;
+        }
+
+        for (i = 0; i < segsize; i++) {
+          irow = glu.lsub(isub);
+          glu.usub(nextu) = perm_r(irow);  // Unlike the L part, the U part is stored in its final order
+          glu.ucol(nextu) = dense(irow);
+          dense(irow) = Scalar(0.0);
+          nextu++;
+          isub++;
+        }
+
+      }  // end nonzero U-segment
+
+    }  // end if jsupno
+
+  }                             // end for each segment
+  glu.xusub(jcol + 1) = nextu;  // close U(*,jcol)
+  return 0;
+}
+
+}  // namespace internal
+}  // end namespace Eigen
+
+#endif  // SPARSELU_COPY_TO_UCOL_H