## Copyright (C) 2000 Paul Kienzle
##
## This program 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 of the License, or
## (at your option) any later version.
##
## This program 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 this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

## -*- texinfo -*-
## @deftypefn {Function File} {} factor (@var{n})
## Return prime factorization of @var{n}.  If n==1, returns 1.
## @end deftypefn

## Author: Paul Kienzle

function x = factor(n)
  if n < 4
    x = n;
  else
    p = primes(sqrt(n));
    q = n./p;
    idx = find (q == fix(q));
    if isempty(idx)
      x = n;
    else
      x = p(idx);
      q = factor(n/prod(p(idx)));
      if q != 1
	x = sort([x, q]);
      endif
    endif
  endif
endfunction