Mercurial > octave
view libinterp/dldfcn/dmperm.cc @ 25054:6652d3823428 stable
maint: Update copyright dates in all source files.
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 30 Mar 2018 09:19:05 -0400 |
parents | 2365c2661b3c |
children | b2917b7858ba |
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/* Copyright (C) 2005-2018 David Bateman Copyright (C) 1998-2005 Andy Adler This file is part of Octave. Octave is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Octave is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Octave; see the file COPYING. If not, see <https://www.gnu.org/licenses/>. */ #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include "CSparse.h" #include "dRowVector.h" #include "dSparse.h" #include "oct-sparse.h" #include "defun-dld.h" #include "errwarn.h" #include "ov.h" #include "ovl.h" #include "utils.h" #if defined (OCTAVE_ENABLE_64) # define CXSPARSE_NAME(name) cs_dl ## name #else # define CXSPARSE_NAME(name) cs_di ## name #endif #if defined (HAVE_CXSPARSE) static RowVector put_int (octave::suitesparse_integer *p, octave_idx_type n) { RowVector ret (n); for (octave_idx_type i = 0; i < n; i++) ret.xelem (i) = p[i] + 1; return ret; } static octave_value_list dmperm_internal (bool rank, const octave_value arg, int nargout) { octave_value_list retval; octave_idx_type nr = arg.rows (); octave_idx_type nc = arg.columns (); SparseMatrix m; SparseComplexMatrix cm; CXSPARSE_NAME () csm; csm.m = nr; csm.n = nc; csm.x = nullptr; csm.nz = -1; if (arg.isreal ()) { m = arg.sparse_matrix_value (); csm.nzmax = m.nnz (); csm.p = octave::to_suitesparse_intptr (m.xcidx ()); csm.i = octave::to_suitesparse_intptr (m.xridx ()); } else { cm = arg.sparse_complex_matrix_value (); csm.nzmax = cm.nnz (); csm.p = octave::to_suitesparse_intptr (cm.xcidx ()); csm.i = octave::to_suitesparse_intptr (cm.xridx ()); } if (nargout <= 1 || rank) { octave::suitesparse_integer *jmatch = CXSPARSE_NAME (_maxtrans) (&csm, 0); if (rank) { octave_idx_type r = 0; for (octave_idx_type i = 0; i < nc; i++) if (jmatch[nr+i] >= 0) r++; retval(0) = static_cast<double>(r); } else retval(0) = put_int (jmatch + nr, nc); CXSPARSE_NAME (_free) (jmatch); } else { CXSPARSE_NAME (d) *dm = CXSPARSE_NAME(_dmperm) (&csm, 0); //retval(5) = put_int (dm->rr, 5); //retval(4) = put_int (dm->cc, 5); retval = ovl (put_int (dm->p, nr), put_int (dm->q, nc), put_int (dm->r, dm->nb+1), put_int (dm->s, dm->nb+1)); CXSPARSE_NAME (_dfree) (dm); } return retval; } #endif DEFUN_DLD (dmperm, args, nargout, doc: /* -*- texinfo -*- @deftypefn {} {@var{p} =} dmperm (@var{S}) @deftypefnx {} {[@var{p}, @var{q}, @var{r}, @var{S}] =} dmperm (@var{S}) @cindex @nospell{Dulmage-Mendelsohn} decomposition Perform a @nospell{Dulmage-Mendelsohn} permutation of the sparse matrix @var{S}. With a single output argument @code{dmperm} performs the row permutations @var{p} such that @code{@var{S}(@var{p},:)} has no zero elements on the diagonal. Called with two or more output arguments, returns the row and column permutations, such that @code{@var{S}(@var{p}, @var{q})} is in block triangular form. The values of @var{r} and @var{S} define the boundaries of the blocks. If @var{S} is square then @code{@var{r} == @var{S}}. The method used is described in: @nospell{A. Pothen & C.-J. Fan.} @cite{Computing the Block Triangular Form of a Sparse Matrix}. @nospell{ACM} Trans. Math. Software, 16(4):303-324, 1990. @seealso{colamd, ccolamd} @end deftypefn */) { #if defined (HAVE_CXSPARSE) if (args.length () != 1) print_usage (); return dmperm_internal (false, args(0), nargout); #else octave_unused_parameter (args); octave_unused_parameter (nargout); err_disabled_feature ("dmperm", "CXSparse"); #endif } /* %!testif HAVE_CXSPARSE %! n = 20; %! a = speye (n,n); %! a = a(randperm (n),:); %! assert (a(dmperm (a),:), speye (n)); %!testif HAVE_CXSPARSE %! n = 20; %! d = 0.2; %! a = tril (sprandn (n,n,d), -1) + speye (n,n); %! a = a(randperm (n), randperm (n)); %! [p,q,r,s] = dmperm (a); %! assert (tril (a(p,q), -1), sparse (n, n)); */ DEFUN_DLD (sprank, args, nargout, doc: /* -*- texinfo -*- @deftypefn {} {@var{p} =} sprank (@var{S}) @cindex structural rank Calculate the structural rank of the sparse matrix @var{S}. Note that only the structure of the matrix is used in this calculation based on a @nospell{Dulmage-Mendelsohn} permutation to block triangular form. As such the numerical rank of the matrix @var{S} is bounded by @code{sprank (@var{S}) >= rank (@var{S})}. Ignoring floating point errors @code{sprank (@var{S}) == rank (@var{S})}. @seealso{dmperm} @end deftypefn */) { #if defined (HAVE_CXSPARSE) if (args.length () != 1) print_usage (); return dmperm_internal (true, args(0), nargout); #else octave_unused_parameter (args); octave_unused_parameter (nargout); err_disabled_feature ("sprank", "CXSparse"); #endif } /* %!testif HAVE_CXSPARSE %! assert (sprank (speye (20)), 20); %!testif HAVE_CXSPARSE %! assert (sprank ([1,0,2,0;2,0,4,0]), 2); %!error sprank (1,2) */