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dbleSCHUR.cc
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1996-03-03
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/*
Copyright (C) 1996 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 2, 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, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#if defined (__GNUG__)
#pragma implementation
#endif
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <iostream.h>
#include "dbleSCHUR.h"
#include "f77-fcn.h"
#include "lo-error.h"
#include "mx-inlines.cc"
extern "C"
{
int F77_FCN (dgeesx, DGEESX) (const char*, const char*,
SCHUR::select_function, const char*,
const int&, double*, const int&,
int&, double*, double*, double*,
const int&, double&, double&, double*,
const int&, int*, const int&, int*,
int&, long, long);
}
static int
select_ana (const double& a, const double&)
{
return (a < 0.0);
}
static int
select_dig (const double& a, const double& b)
{
return (hypot (a, b) < 1.0);
}
int
SCHUR::init (const Matrix& a, const string& ord)
{
int a_nr = a.rows ();
int a_nc = a.cols ();
if (a_nr != a_nc)
{
(*current_liboctave_error_handler) ("SCHUR requires square matrix");
return -1;
}
char jobvs = 'V';
char sense = 'N';
char sort = 'N';
char ord_char = ord.empty () ? 'U' : ord[0];
if (ord_char == 'A' || ord_char == 'D' || ord_char == 'a' || ord_char == 'd')
sort = 'S';
if (ord_char == 'A' || ord_char == 'a')
selector = select_ana;
else if (ord_char == 'D' || ord_char == 'd')
selector = select_dig;
else
selector = 0;
int n = a_nc;
int lwork = 8 * n;
int liwork = 1;
int info;
int sdim;
double rconde;
double rcondv;
schur_mat = a;
unitary_mat.resize (n, n);
double *s = schur_mat.fortran_vec ();
double *q = unitary_mat.fortran_vec ();
Array<double> wr (n);
double *pwr = wr.fortran_vec ();
Array<double> wi (n);
double *pwi = wi.fortran_vec ();
Array<double> work (lwork);
double *pwork = work.fortran_vec ();
// These are not referenced for the non-ordered Schur routine.
Array<int> bwork;
Array<int> iwork;
if (ord_char == 'A' || ord_char == 'D' || ord_char == 'a' || ord_char == 'd')
{
bwork.resize (n);
iwork.resize (liwork);
}
int *pbwork = bwork.fortran_vec ();
int *piwork = iwork.fortran_vec ();
F77_XFCN (dgeesx, DGEESX, (&jobvs, &sort, selector, &sense, n, s,
n, sdim, pwr, pwi, q, n, rconde, rcondv,
pwork, lwork, piwork, liwork, pbwork,
info, 1L, 1L));
if (f77_exception_encountered)
(*current_liboctave_error_handler) ("unrecoverable error in dgeesx");
return info;
}
ostream&
operator << (ostream& os, const SCHUR& a)
{
os << a.schur_matrix () << "\n";
os << a.unitary_matrix () << "\n";
return os;
}
/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/