Mercurial > octave
view liboctave/array/PermMatrix.cc @ 30564:796f54d4ddbf stable
update Octave Project Developers copyright for the new year
In files that have the "Octave Project Developers" copyright notice,
update for 2021.
In all .txi and .texi files except gpl.txi and gpl.texi in the
doc/liboctave and doc/interpreter directories, change the copyright
to "Octave Project Developers", the same as used for other source
files. Update copyright notices for 2022 (not done since 2019). For
gpl.txi and gpl.texi, change the copyright notice to be "Free Software
Foundation, Inc." and leave the date at 2007 only because this file
only contains the text of the GPL, not anything created by the Octave
Project Developers.
Add Paul Thomas to contributors.in.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Tue, 28 Dec 2021 18:22:40 -0500 |
parents | 29a1f8fd8ee6 |
children | 597f3ee61a48 |
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//////////////////////////////////////////////////////////////////////// // // Copyright (C) 2008-2022 The Octave Project Developers // // See the file COPYRIGHT.md in the top-level directory of this // distribution or <https://octave.org/copyright/>. // // 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 "PermMatrix.h" #include "idx-vector.h" #include "Array-util.h" #include "oct-locbuf.h" OCTAVE_NORETURN static void err_invalid_permutation (void) { (*current_liboctave_error_handler) ("PermMatrix: invalid permutation vector"); } void PermMatrix::setup (const Array<octave_idx_type>& p, bool colp, bool check) { if (check) { if (! octave::idx_vector (p).is_permutation (p.numel ())) err_invalid_permutation (); } if (! colp) *this = this->transpose (); } PermMatrix::PermMatrix (const Array<octave_idx_type>& p, bool colp, bool check) : Array<octave_idx_type> (p) { setup (p, colp, check); } void PermMatrix::setup (const octave::idx_vector& idx, bool colp, octave_idx_type n) { octave_idx_type len = idx.length (n); if (! idx.is_permutation (len)) err_invalid_permutation (); Array<octave_idx_type> idxa (dim_vector (len, 1)); for (octave_idx_type i = 0; i < len; i++) idxa(i) = idx(i); Array<octave_idx_type>::operator = (idxa); if (! colp) *this = this->transpose (); } PermMatrix::PermMatrix (const octave::idx_vector& idx, bool colp, octave_idx_type n) : Array<octave_idx_type> () { setup (idx, colp, n); } PermMatrix::PermMatrix (octave_idx_type n) : Array<octave_idx_type> (dim_vector (n, 1)) { for (octave_idx_type i = 0; i < n; i++) xelem (i) = i; } octave_idx_type PermMatrix::checkelem (octave_idx_type i, octave_idx_type j) const { octave_idx_type len = Array<octave_idx_type>::numel (); if (i < 0 || j < 0 || i > len || j > len) (*current_liboctave_error_handler) ("index out of range"); return elem (i, j); } PermMatrix PermMatrix::transpose (void) const { octave_idx_type len = Array<octave_idx_type>::numel (); PermMatrix retval (len); for (octave_idx_type i = 0; i < len; ++i) retval.xelem (xelem (i)) = i; return retval; } PermMatrix PermMatrix::inverse (void) const { return transpose (); } octave_idx_type PermMatrix::determinant (void) const { // Determine the sign of a permutation in linear time. // Is this widely known? octave_idx_type len = perm_length (); const octave_idx_type *pa = data (); OCTAVE_LOCAL_BUFFER (octave_idx_type, p, len); OCTAVE_LOCAL_BUFFER (octave_idx_type, q, len); for (octave_idx_type i = 0; i < len; i++) { p[i] = pa[i]; q[p[i]] = i; } bool neg = false; for (octave_idx_type i = 0; i < len; i++) { octave_idx_type j = p[i]; octave_idx_type k = q[i]; if (j != i) { p[k] = p[i]; q[j] = q[i]; neg = ! neg; } } return neg ? -1 : 1; } PermMatrix PermMatrix::power(octave_idx_type m) const { if (m < 0) return inverse ().pos_power (-m); else if (m > 0) return pos_power (m); else return PermMatrix (rows ()); } PermMatrix PermMatrix::pos_power (octave_idx_type m) const { octave_idx_type n = rows (); const octave_idx_type *p = data (); Array<octave_idx_type> res_pvec (dim_vector (n, 1), -1); octave_idx_type *q = res_pvec.fortran_vec (); for (octave_idx_type ics = 0; ics < n; ics++) { if (q[ics] > 0) continue; // go forward m steps or until a cycle is found. octave_idx_type ic, j; for (j = 1, ic = p[ics]; j != m && ic != ics; j++, ic = p[ic]) ; if (ic == ics) { // reduce power. octave_idx_type mm = m % j; // go forward mm steps. for (j = 0, ic = ics; j != mm; j++, ic = p[ic]) ; } // now ic = p^m[ics]. Loop through the whole cycle. octave_idx_type jcs = ics; do { q[jcs] = ic; jcs = p[jcs]; ic = p[ic]; } while (jcs != ics); } return PermMatrix (res_pvec, true, false); } PermMatrix PermMatrix::eye (octave_idx_type n) { return PermMatrix (n); } PermMatrix operator *(const PermMatrix& a, const PermMatrix& b) { PermMatrix r; const Array<octave_idx_type> ia = a.col_perm_vec (); const Array<octave_idx_type> ib = b.col_perm_vec (); octave_idx_type n = a.columns (); if (n != b.rows ()) octave::err_nonconformant ("operator *", n, n, b.rows (), b.rows ()); r = PermMatrix (ia.index (octave::idx_vector (ib)), true, false); return r; }