## [f62e8c]: inst / @galois / deconv.m Maximize Restore History

Download this file

### deconv.m    84 lines (71 with data), 2.5 kB

 ``` 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 81 82 83``` ```## Copyright (C) 2002 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 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 . ## -*- texinfo -*- ## @deftypefn {Function File} {} deconv (@var{y}, @var{a}) ## Deconvolve two Galois vectors. ## ## @code{[b, r] = deconv (y, a)} solves for @var{b} and @var{r} such that ## @code{y = conv (a, b) + r}. ## ## If @var{y} and @var{a} are polynomial coefficient vectors, @var{b} will ## contain the coefficients of the polynomial quotient and @var{r} will be ## a remainder polynomial of lowest order. ## @seealso{conv} ## @end deftypefn function [b, r] = deconv (y, a) if (nargin != 2) print_usage (); endif if (!isgalois (y) && !isgalois (a)) error ("deconv: at least one argument must be a galois variable"); elseif (!isgalois (y)) y = gf (y, a.m, a.prim_poly); elseif (!isgalois (a)) a = gf (a, y.m, y.prim_poly); elseif (a.m != y.m && a.prim_poly != y.prim_poly) error ("deconv: both vectors must be in the same galois field"); endif if (min (size (a)) > 1 || min (size (y)) > 1) error ("deconv: both arguments must be vectors"); endif la = length (a); ly = length (y); lb = ly - la + 1; ## Ensure that both vectors are row vectors. if (rows (a) > 1) a = reshape (a, 1, la); endif if (rows (y) > 1) y = reshape (y, 1, ly); endif if (ly > la) b = filter (y, a, [1, (zeros (1, ly - la))]); elseif (ly == la) b = filter (y, a, 1); else b = gf (0, y.m, y.prim_poly); endif lc = la + length (b) - 1; if (ly == lc) r = y - conv (a, b); else ## Can't concatenate galois variables like this yet ## r = [(zeros (1, lc - ly)), y] - conv (a, b); r = gf ([(zeros (1, lc - ly)), y], y.m, y.prim_poly) - conv (a, b); endif endfunction %%Test input validation %!error deconv (gf (1, 2), gf (1, 3)) %!error deconv (gf (eye (3), 3), gf (eye (3), 3)) ```