Mercurial > forge
view main/comm/de2bi.m @ 770:039e2a73aa8d octave-forge
R13 compatible galois field support
author | pkienzle |
---|---|
date | Thu, 06 Feb 2003 05:14:59 +0000 |
parents | 6b33357c7561 |
children | 1ecdc9a0ab5e |
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## Copyright (C) 2001 Laurent Mazet ## ## 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} {@var{b} = } de2bi (@var{d}) ## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n}) ## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n},@var{p}) ## @deftypefnx {Function File} {@var{b} = } de2bi (@var{d},@var{n},@var{p},@var{f}) ## ## Convert a non-negative integer to bit vector. ## ## The variable @var{d} must be a vector of non-negative integers. @dfn{de2bi} ## then returns a matrix where each row represents the binary representation ## of elements of @var{d}. If @var{n} is defined then the returned matrix ## will have @var{n} columns. This number of columns can be either larger ## than the minimum needed and zeros will be added to the msb of the ## binary representation or smaller than the minimum in which case the ## least-significant part of the element is returned. ## ## If @var{p} is defined then it is used as the base for the decomposition ## of the returned values. That is the elements of the returned value are ## between '0' and 'p-1'. ## ## The variable @var{f} defines whether the first or last element of @var{b} ## is considered to be the most-significant. Valid values of @var{f} are ## 'right-msb' or 'left-msb'. By default @var{f} is 'right-msb'. ## @end deftypefn ## @seealso{bi2de} ## 2001-02-02 ## initial release ## 2003-02-02 ## add orientation of b and help in texinfo function b = de2bi(d, n, p, f) if (nargin == 1) p = 2; n = floor ( log (max (max (d), 1)) ./ log (p) ) + 1; f = 'right-msb'; elseif (nargin == 2) p = 2; if (isstr(n)) f = n; n = floor ( log (max (max (d), 1)) ./ log (p) ) + 1; else f = 'right-msb'; endif elseif (nargin == 3) if (isstr(n)) f = n; n = p p = 2; elseif (isstr(p)) f = p; p = 2; else f = 'right-msb'; endif elseif (nargin == 3) if (isstr(n)) tmp = f f = n; n = p p = tmp; elseif (isstr(p)) tmp = f; f = p; p = tmp; endif else error ("usage: b = de2bi (d [, n [, p]])"); endif d = d(:); if ( any (d < 0) || any (d != floor (d)) ) error ("de2bi: only handles non-negative integers"); endif power = ones (length (d), 1) * (p .^ [0 : n-1] ); d = d * ones (1, n); b = floor (rem (d, p*power) ./ power); if (strcmp(f,'left-msb')) b = b(:,length(b):-1:1); elseif (!strcmp(f,'right-msb')) error("de2bi: unrecognized flag"); endif endfunction