# Copyright (C) 1993 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, 675 Mass Ave, Cambridge, MA 02139, USA.

function retval = cond (a)

# usage: cond (a)
#
# Return the condition number of a, computed using the singular values
# of a.
#
# See also: norm, svd

  if (nargin == 1)
    [nr, nc] = size (a);
    if (nr == 0 && nc == 0)
      if (strcmp (propagate_empty_matrices, "false"))
        error ("cond: empty matrix is invalid as argument");
      endif
      if (strcmp (propagate_empty_matrices, "warn"))
        printf ("warning: cond: argument is empty matrix\n");
      endif
      retval = 0.0;
    endif
    sigma = svd (a);
    retval = sigma (1) / sigma (length (sigma));
  else
    error ("usage: cond (a)");
  endif

endfunction