--- a +++ b/inst/@gf/sqrt.m @@ -0,0 +1,30 @@ +## Copyright (C) 2011 David Bateman +## +## 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, see <http://www.gnu.org/licenses/>. + +## -*- texinfo -*- +## @deftypefn {Function File} {} sqrt (@var{x}) +## Compute the square-root for each element of @var{x} for a Galois +## array. +## @end deftypefn + +function y = sqrt (g) + tmp = g._index_of(g._x + 1); + y = g._alpha_to(floor((tmp + bitand(tmp, 1) * g._n) / 2 + 1)); +endfunction + +%!shared g +%! g = gf([0,2,4,6;1,3,5,7],3); +%!assert(sqrt(g), gf([0,6,2,4;1,7,3,5],3) +%!assert(sqrt(g) .* sqrt(g), g)