## Copyright (C) 2003 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} {@var{w} = } gfweight (@var{gen}) ## @deftypefnx {Function File} {@var{w} = } gfweight (@var{gen},'gen') ## @deftypefnx {Function File} {@var{w} = } gfweight (@var{par},'par') ## @deftypefnx {Function File} {@var{w} = } gfweight (@var{p},n) ## ## Calculate the minimum weight or distance of a linear block code. The ## code can be either defined by its generator or parity check matrix, or ## its generator polynomial. By default if the first argument is a matrix, ## it is assumed to be the generator matrix of the code. The type of the ## matrix can be defined by a flag 'gen' for the generator matrix or ## 'par' for the parity check matrix. ## ## If the first argument is a vector, it is assumed that it defines the ## generator polynomial of the code. In this case a second argument is ## required that defines the codeword length. ## ## @end deftypefn ## @seealso{hammgen,cyclpoly,bchpoly} function w = gfweight (arg1, arg2) if ((nargin < 1) || (nargin > 2)) usage ("gfweight(mat,typ) or gfweight(poly,n)"); endif if (isvector(arg1)) if (nargin != 2) error ("gfweight: need the codeword length if passing generator polynomial"); endif [ign, gen] = cyclgen(arg2, arg1); elseif (ismatrix(arg1)) if (nargin == 2) if (ischar(arg2)) if (strcmp(arg2,"gen")) gen = arg1; elseif (strcmp(arg2,"par")) gen = gen2par(arg1); else error ("gfweight: unrecognized string argument"); endif else error ("gfweight: if first argument is a matrix, the second must be a string"); endif else gen = arg1; endif else error ("gfweight: first argument must be a matrix or a vector"); endif [k, n] = size(gen); if (n < k) error ("gfweight: generator matrix in an illegal form"); endif ## We only need to test codewords 1:2^k-1 against the zero code word ## We do the equivalent of ## w = min(sum((mod(de2bi([1:2^k-1]') * gen, 2))')); ## But in a more memory efficient manner in an oct-file w = __gfweight__(gen); endfunction

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