## Copyright (C) 2015 Markus Bergholz <markuman@gmail.com>
##
## 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 3 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, see <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn {Function File} {} roundn (@var{X})
## Returns the integer nearest to @var{x} when no 2nd argument is given.
##
## @deftypefnx {Function File} {} roundn (@var{X}, @var{n})
## Returns the double nearest multiply of 10^@var{n}, while @var{n} has to be an integer scalar.
##
## When @var{X} is an integer, it rounds to the nearest decimal power.
##
## @seealso{round ceil floor fix roundb}
## @end deftypefn



function ret = roundn(x, n = 0)

  if (mod(x, 1) ~= 0)

    ret = round(10^abs(n)*x)/(10^abs(n));
    
  else
  
    ret = round(x / 10^abs(n)) * 10 ^ abs(n);
  
  endif  

endfunction

%!assert (roundn(pi), 3)
%!assert (roundn(e, -2), 2.7200)
%!assert (roundn(pi,4), 3.1416)
%!assert (roundn(e, 3), 2.718)
%!assert (roundn([0.197608841252122, 0.384415323084123; 0.213847642260694, 0.464622347858917],2), [0.20, 0.38; 0.21, 0.46])
%!assert (roundn(401189, 3), 401000)
%!assert (roundn(5), 5)
%!assert (roundn(-5), -5)

