--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/liboctave/fCmplxSVD.cc	Sun Apr 27 22:34:17 2008 +0200
@@ -0,0 +1,173 @@
+/*
+
+Copyright (C) 1994, 1995, 1996, 1997, 1999, 2002, 2003, 2004, 2005,
+              2007 John W. Eaton
+
+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
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "fCmplxSVD.h"
+#include "f77-fcn.h"
+#include "lo-error.h"
+
+extern "C"
+{
+  F77_RET_T
+  F77_FUNC (cgesvd, CGESVD) (F77_CONST_CHAR_ARG_DECL,
+			     F77_CONST_CHAR_ARG_DECL,
+			     const octave_idx_type&, const octave_idx_type&, FloatComplex*,
+			     const octave_idx_type&, float*, FloatComplex*, const octave_idx_type&,
+			     FloatComplex*, const octave_idx_type&, FloatComplex*, const octave_idx_type&,
+			     float*, octave_idx_type&
+			     F77_CHAR_ARG_LEN_DECL
+			     F77_CHAR_ARG_LEN_DECL);
+}
+
+FloatComplexMatrix
+FloatComplexSVD::left_singular_matrix (void) const
+{
+  if (type_computed == SVD::sigma_only)
+    {
+      (*current_liboctave_error_handler)
+	("FloatComplexSVD: U not computed because type == SVD::sigma_only");
+      return FloatComplexMatrix ();
+    }
+  else
+    return left_sm;
+}
+
+FloatComplexMatrix
+FloatComplexSVD::right_singular_matrix (void) const
+{
+  if (type_computed == SVD::sigma_only)
+    {
+      (*current_liboctave_error_handler)
+	("FloatComplexSVD: V not computed because type == SVD::sigma_only");
+      return FloatComplexMatrix ();
+    }
+  else
+    return right_sm;
+}
+
+octave_idx_type
+FloatComplexSVD::init (const FloatComplexMatrix& a, SVD::type svd_type)
+{
+  octave_idx_type info;
+
+  octave_idx_type m = a.rows ();
+  octave_idx_type n = a.cols ();
+
+  FloatComplexMatrix atmp = a;
+  FloatComplex *tmp_data = atmp.fortran_vec ();
+
+  octave_idx_type min_mn = m < n ? m : n;
+  octave_idx_type max_mn = m > n ? m : n;
+
+  char jobu = 'A';
+  char jobv = 'A';
+
+  octave_idx_type ncol_u = m;
+  octave_idx_type nrow_vt = n;
+  octave_idx_type nrow_s = m;
+  octave_idx_type ncol_s = n;
+
+  switch (svd_type)
+    {
+    case SVD::economy:
+      jobu = jobv = 'S';
+      ncol_u = nrow_vt = nrow_s = ncol_s = min_mn;
+      break;
+
+    case SVD::sigma_only:
+
+      // Note:  for this case, both jobu and jobv should be 'N', but
+      // there seems to be a bug in dgesvd from Lapack V2.0.  To
+      // demonstrate the bug, set both jobu and jobv to 'N' and find
+      // the singular values of [eye(3), eye(3)].  The result is
+      // [-sqrt(2), -sqrt(2), -sqrt(2)].
+      //
+      // For Lapack 3.0, this problem seems to be fixed.
+
+      jobu = 'N';
+      jobv = 'N';
+      ncol_u = nrow_vt = 1;
+      break;
+
+    default:
+      break;
+    }
+
+  type_computed = svd_type;
+
+  if (! (jobu == 'N' || jobu == 'O'))
+    left_sm.resize (m, ncol_u);
+
+  FloatComplex *u = left_sm.fortran_vec ();
+
+  sigma.resize (nrow_s, ncol_s);
+  float *s_vec = sigma.fortran_vec ();
+
+  if (! (jobv == 'N' || jobv == 'O'))
+    right_sm.resize (nrow_vt, n);
+
+  FloatComplex *vt = right_sm.fortran_vec ();
+
+  octave_idx_type lrwork = 5*max_mn;
+
+  Array<float> rwork (lrwork);
+
+  // Ask ZGESVD what the dimension of WORK should be.
+
+  octave_idx_type lwork = -1;
+
+  Array<FloatComplex> work (1);
+
+  F77_XFCN (cgesvd, CGESVD, (F77_CONST_CHAR_ARG2 (&jobu, 1),
+			     F77_CONST_CHAR_ARG2 (&jobv, 1),
+			     m, n, tmp_data, m, s_vec, u, m, vt,
+			     nrow_vt, work.fortran_vec (), lwork,
+			     rwork.fortran_vec (), info
+			     F77_CHAR_ARG_LEN (1)
+			     F77_CHAR_ARG_LEN (1)));
+
+  lwork = static_cast<octave_idx_type> (work(0).real ());
+  work.resize (lwork);
+
+  F77_XFCN (cgesvd, CGESVD, (F77_CONST_CHAR_ARG2 (&jobu, 1),
+			     F77_CONST_CHAR_ARG2 (&jobv, 1),
+			     m, n, tmp_data, m, s_vec, u, m, vt,
+			     nrow_vt, work.fortran_vec (), lwork,
+			     rwork.fortran_vec (), info
+			     F77_CHAR_ARG_LEN (1)
+			     F77_CHAR_ARG_LEN (1)));
+
+  if (! (jobv == 'N' || jobv == 'O'))
+    right_sm = right_sm.hermitian ();
+
+  return info;
+}
+
+/*
+;;; Local Variables: ***
+;;; mode: C++ ***
+;;; End: ***
+*/