/usr/share/octave/packages/communications-1.1.1/ricedeco.m is in octave-communications-common 1.1.1-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 | ## Copyright (C) 2006 Muthiah Annamalai <muthiah.annamalai@uta.edu>
##
## 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} {} ricedeco (@var{code}, @var{K})
##
## Returns the Rice decoded signal vector using @var{code} and @var{K}.
## Compulsory K is need to be specified.
## A restrictions is that a signal set must strictly be non-negative.
## The value of code is a cell array of row-vectors which have the
## encoded rice value for a single sample. The Rice algorithm is
## used to encode the 'code' and only that can be meaningfully
## decoded. @var{code} is assumed to have been of format generated
## by the function @code{riceenco}.
##
## Reference: Solomon Golomb, Run length Encodings, 1966 IEEE Trans Info' Theory
##
## An exmaple of the use of @code{ricedeco} is
## @example
## @group
## ricedec(riceenco(1:4,2),2)
##
## @end group
## @end example
## @end deftypefn
## @seealso{riceenco}
##
##
##! /usr/bin/octave -q
##A stress test routine
##for i=1:100
## sig=abs(randint(1,10,[0,255]));
## [code,k]=riceenco(sig)
## sig_d=ricedeco(code,k)
## if(isequal(sig_d,sig)~=1)
## error('Some mistake in ricedeco/enco pair');
## end
##end
##
function sig_op=ricedeco(code,K)
if ( nargin < 2 ) || (strcmp(class(code),"cell")~=1)
error('usage: ricedeco(code,K)');
end
L=length(code);
K_pow_2=2**K;
if(K ~= 0)
power_seq=[2.^((K-1):-1:0)];
for j=1:L
word=code{j};
idx=find(word==0)(1);
val=sum(word(1:idx));
sig_op(j)=val*K_pow_2 + sum(word(idx+1:end).*power_seq);
end
else
for j=1:L
sig_op(j)=sum(code{j});
end
end
return
end
%!
%! assert(ricedeco(riceenco(1:4,2),2),[1:4])
%!
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