## Copyright (C) 2003, 2005, 2006, 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/>.

## -*- texinfo -*-
## @deftypefn {Function File} {} logm (@var{a})
## Compute the matrix logarithm of the square matrix @var{a}.  Note that
## this is currently implemented in terms of an eigenvalue expansion and
## needs to be improved to be more robust.
## @end deftypefn

function B = logm (A)

  if (nargin != 1)
    print_usage ();
  endif

  [V, D] = eig (A);
  B = V * diag (log (diag (D))) * inv (V);

endfunction