GNU Octave  3.8.0
A high-level interpreted language, primarily intended for numerical computations, mostly compatible with Matlab
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CmplxQRP.cc
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1 /*
2 
3 Copyright (C) 1994-2013 John W. Eaton
4 Copyright (C) 2009 VZLU Prague
5 
6 This file is part of Octave.
7 
8 Octave is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 3 of the License, or (at your
11 option) any later version.
12 
13 Octave is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17 
18 You should have received a copy of the GNU General Public License
19 along with Octave; see the file COPYING. If not, see
20 <http://www.gnu.org/licenses/>.
21 
22 */
23 
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27 
28 #include <cassert>
29 
30 #include "CmplxQRP.h"
31 #include "f77-fcn.h"
32 #include "lo-error.h"
33 #include "oct-locbuf.h"
34 
35 extern "C"
36 {
37  F77_RET_T
38  F77_FUNC (zgeqp3, ZGEQP3) (const octave_idx_type&, const octave_idx_type&,
39  Complex*, const octave_idx_type&,
40  octave_idx_type*, Complex*, Complex*,
41  const octave_idx_type&, double*,
42  octave_idx_type&);
43 }
44 
45 // It would be best to share some of this code with ComplexQR class...
46 
48  : ComplexQR (), p ()
49 {
50  init (a, qr_type);
51 }
52 
53 void
55 {
56  assert (qr_type != qr_type_raw);
57 
58  octave_idx_type m = a.rows ();
59  octave_idx_type n = a.cols ();
60 
61  octave_idx_type min_mn = m < n ? m : n;
62  OCTAVE_LOCAL_BUFFER (Complex, tau, min_mn);
63 
64  octave_idx_type info = 0;
65 
66  ComplexMatrix afact = a;
67  if (m > n && qr_type == qr_type_std)
68  afact.resize (m, m);
69 
70  MArray<octave_idx_type> jpvt (dim_vector (n, 1), 0);
71 
72  if (m > 0)
73  {
74  OCTAVE_LOCAL_BUFFER (double, rwork, 2*n);
75 
76  // workspace query.
77  Complex clwork;
78  F77_XFCN (zgeqp3, ZGEQP3, (m, n, afact.fortran_vec (),
79  m, jpvt.fortran_vec (), tau,
80  &clwork, -1, rwork, info));
81 
82  // allocate buffer and do the job.
83  octave_idx_type lwork = clwork.real ();
84  lwork = std::max (lwork, static_cast<octave_idx_type> (1));
85  OCTAVE_LOCAL_BUFFER (Complex, work, lwork);
86  F77_XFCN (zgeqp3, ZGEQP3, (m, n, afact.fortran_vec (),
87  m, jpvt.fortran_vec (), tau,
88  work, lwork, rwork, info));
89  }
90  else
91  for (octave_idx_type i = 0; i < n; i++) jpvt(i) = i+1;
92 
93  // Form Permutation matrix (if economy is requested, return the
94  // indices only!)
95 
96  jpvt -= static_cast<octave_idx_type> (1);
97  p = PermMatrix (jpvt, true);
98 
99 
100  form (n, afact, tau, qr_type);
101 }
102 
103 RowVector
104 ComplexQRP::Pvec (void) const
105 {
106  Array<double> pa (p.pvec ());
107  RowVector pv (MArray<double> (pa) + 1.0);
108  return pv;
109 }