home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Cream of the Crop 26
/
Cream of the Crop 26.iso
/
os2
/
octa209s.zip
/
octave-2.09
/
src
/
balance.cc
< prev
next >
Wrap
C/C++ Source or Header
|
1996-11-03
|
6KB
|
287 lines
/*
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.
*/
// Written by A. S. Hodel <scotte@eng.auburn.edu>
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string>
#include "CmplxAEPBAL.h"
#include "CmplxAEPBAL.h"
#include "dbleAEPBAL.h"
#include "dbleAEPBAL.h"
#include "dbleGEPBAL.h"
#include "defun-dld.h"
#include "error.h"
#include "gripes.h"
#include "help.h"
#include "oct-obj.h"
#include "utils.h"
DEFUN_DLD (balance, args, nargout,
"AA = balance (A [, OPT]) or [[DD,] AA] = balance (A [, OPT])\n\
\n\
generalized eigenvalue problem:\n\
\n\
[cc, dd, aa, bb] = balance (a, b [, opt])\n\
\n\
where OPT is an optional single character argument as follows: \n\
\n\
N: no balancing; arguments copied, transformation(s) set to identity\n\
P: permute argument(s) to isolate eigenvalues where possible\n\
S: scale to improve accuracy of computed eigenvalues\n\
B: (default) permute and scale, in that order. Rows/columns\n\
of a (and b) that are isolated by permutation are not scaled\n\
\n\
[DD, AA] = balance (A, OPT) returns aa = dd*a*dd,\n\
\n\
[CC, DD, AA, BB] = balance (A, B, OPT) returns AA (BB) = CC*A*DD (CC*B*DD)")
{
octave_value_list retval;
int nargin = args.length ();
if (nargin < 1 || nargin > 3 || nargout < 0 || nargout > 4)
{
print_usage ("balance");
return retval;
}
string bal_job;
int my_nargin; // # args w/o optional string arg
// Determine if balancing option is listed. Set my_nargin to the
// number of matrix inputs.
if (args(nargin-1).is_string ())
{
bal_job = args(nargin-1).string_value ();
my_nargin = nargin-1;
}
else
{
bal_job = "B";
my_nargin = nargin;
}
octave_value arg_a = args(0);
int a_nr = arg_a.rows ();
int a_nc = arg_a.columns ();
// Check argument 1 dimensions.
int arg_is_empty = empty_arg ("balance", a_nr, a_nc);
if (arg_is_empty < 0)
return retval;
if (arg_is_empty > 0)
return octave_value_list (2, Matrix ());
if (a_nr != a_nc)
{
gripe_square_matrix_required ("balance");
return retval;
}
// Extract argument 1 parameter for both AEP and GEP.
Matrix aa;
ComplexMatrix caa;
if (arg_a.is_complex_type ())
caa = arg_a.complex_matrix_value ();
else
aa = arg_a.matrix_value ();
if (error_state)
return retval;
// Treat AEP/GEP cases.
switch (my_nargin)
{
case 1:
// Algebraic eigenvalue problem.
if (arg_a.is_complex_type ())
{
ComplexAEPBALANCE result (caa, bal_job);
if (nargout == 0 || nargout == 1)
retval(0) = result.balanced_matrix ();
else
{
retval(1) = result.balanced_matrix ();
retval(0) = result.balancing_matrix ();
}
}
else
{
AEPBALANCE result (aa, bal_job);
if (nargout == 0 || nargout == 1)
retval(0) = result.balanced_matrix ();
else
{
retval(1) = result.balanced_matrix ();
retval(0) = result.balancing_matrix ();
}
}
break;
case 2:
{
// Generalized eigenvalue problem.
// 1st we have to check argument 2 dimensions and type...
octave_value arg_b = args(1);
int b_nr = arg_b.rows ();
int b_nc = arg_b.columns ();
// Check argument 2 dimensions -- must match arg 1.
if (b_nr != b_nc || b_nr != a_nr)
{
gripe_nonconformant ();
return retval;
}
// Now, extract the second matrix...
// Extract argument 1 parameter for both AEP and GEP.
Matrix bb;
ComplexMatrix cbb;
if (arg_b.is_complex_type ())
cbb = arg_b.complex_matrix_value ();
else
bb = arg_b.matrix_value ();
if (error_state)
return retval;
// Both matrices loaded, now let's check what kind of arithmetic:
if (arg_a.is_complex_type () || arg_b.is_complex_type ())
{
if (arg_a.is_real_type ())
caa = aa;
if (arg_b.is_real_type ())
cbb = bb;
// Compute magnitudes of elements for balancing purposes.
// Surely there's a function I can call someplace!
for (int i = 0; i < a_nr; i++)
for (int j = 0; j < a_nc; j++)
{
aa (i, j) = abs (caa (i, j));
bb (i, j) = abs (cbb (i, j));
}
}
GEPBALANCE result (aa, bb, bal_job);
if (arg_a.is_complex_type () || arg_b.is_complex_type ())
{
caa = result.left_balancing_matrix () * caa
* result.right_balancing_matrix ();
cbb = result.left_balancing_matrix () * cbb
* result.right_balancing_matrix ();
switch (nargout)
{
case 0:
case 1:
warning ("balance: should use two output arguments");
retval(0) = caa;
break;
case 2:
retval(1) = cbb;
retval(0) = caa;
break;
case 4:
retval(3) = cbb;
retval(2) = caa;
retval(1) = result.right_balancing_matrix ();
retval(0) = result.left_balancing_matrix ();
break;
default:
error ("balance: invalid number of output arguments");
break;
}
}
else
{
switch (nargout)
{
case 0:
case 1:
warning ("balance: should use two output arguments");
retval(0) = result.balanced_a_matrix ();
break;
case 2:
retval(1) = result.balanced_b_matrix ();
retval(0) = result.balanced_a_matrix ();
break;
case 4:
retval(3) = result.balanced_b_matrix ();
retval(2) = result.balanced_a_matrix ();
retval(1) = result.right_balancing_matrix ();
retval(0) = result.left_balancing_matrix ();
break;
default:
error ("balance: invalid number of output arguments");
break;
}
}
}
break;
default:
error ("balance requires one (AEP) or two (GEP) numeric arguments");
break;
}
return retval;
}
/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/