## [05b386]: inst / @gf / diag.m  Maximize  Restore  History

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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``` ```## 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 . ## -*- texinfo -*- ## @deftypefn {Function File} {} diag (@var{v}, @var{k}) ## Return a diagonal matrix with Galois vector @var{v} on diagonal @var{k}. ## The second argument is optional. If it is positive, the vector is placed on ## the @var{k}-th super-diagonal. If it is negative, it is placed on the ## @var{-k}-th sub-diagonal. The default value of @var{k} is 0, and the ## vector is placed on the main diagonal. For example, ## ## @example ## diag (gf([1, 2, 3],2), 1) ## ans = ## GF(2^2) array. Primitive Polynomial = D^2+D+1 (decimal 7) ## ## Array elements = ## ## 0 1 0 0 ## 0 0 2 0 ## 0 0 0 3 ## 0 0 0 0 ## @end example ## @end deftypefn function y = diag (g, varargin) y = g; y._x = diag (y._x, varargin{:}); endfunction %!assert(diag(gf([1; 2; 3], 3)), gf([1, 0, 0; 0, 2, 0; 0, 0, 3], 3)); %!assert(diag (gf([1; 2; 3], 3), 1), gf([0, 1, 0, 0; 0, 0, 2, 0; 0, 0, 0, 3; 0, 0, 0, 0], 3)); %!assert(diag (gf([1; 2; 3], 3), 2), gf([0, 0, 1, 0, 0; 0, 0, 0, 2, 0; 0, 0, 0, 0, 3; 0, 0, 0, 0, 0; 0, 0, 0, 0, 0], 3)); %!assert(diag (gf([1; 2; 3], 3),-1), gf([0, 0, 0, 0; 1, 0, 0, 0; 0, 2, 0, 0; 0, 0, 3, 0], 3)); %!assert(diag (gf([1; 2; 3], 3),-2), gf([0, 0, 0, 0, 0; 0, 0, 0, 0, 0; 1, 0, 0, 0, 0; 0, 2, 0, 0, 0; 0, 0, 3, 0, 0], 3)); %!assert(diag (gf([1, 0, 0; 0, 2, 0; 0, 0, 3], 3)), gf([1; 2; 3], 3)); %!assert(diag (gf([0, 1, 0, 0; 0, 0, 2, 0; 0, 0, 0, 3; 0, 0, 0, 0], 3), 1), gf([1; 2; 3],3)); %!assert(diag (gf([0, 0, 0, 0; 1, 0, 0, 0; 0, 2, 0, 0; 0, 0, 3, 0], 3), -1), gf([1; 2; 3], 3)); %!assert(diag (gf(ones(1, 0), 3), 2), gf(zeros (2), 3)); %!assert(diag (gf(1:3, 3), 4, 2), gf([1, 0; 0, 2; 0, 0; 0, 0], 3)); ```