/usr/share/octave/packages/communications-1.1.1/randerr.m is in octave-communications-common 1.1.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | ## 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 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} {@var{b} = } randerr (@var{n})
## @deftypefnx {Function File} {@var{b} = } randerr (@var{n},@var{m})
## @deftypefnx {Function File} {@var{b} = } randerr (@var{n},@var{m},@var{err})
## @deftypefnx {Function File} {@var{b} = } randerr (@var{n},@var{m},@var{err},@var{seed})
##
## Generate a matrix of random bit errors. The size of the matrix is
## @var{n} rows by @var{m} columns. By default @var{m} is equal to @var{n}.
## Bit errors in the matrix are indicated by a 1.
##
## The variable @var{err} determines the number of errors per row. By
## default the return matrix @var{b} has exactly one bit error per row.
## If @var{err} is a scalar, there each row of @var{b} has exactly this
## number of errors per row. If @var{err} is a vector then each row has
## a number of errors that is in this vector. Each number of errors has
## an equal probability. If @var{err} is a matrix with two rows, then
## the first row determines the number of errors and the second their
## probabilities.
##
## The variable @var{seed} allows the random number generator to be seeded
## with a fixed value. The initial seed will be restored when returning.
## @end deftypefn
## 2003 FEB 13
## initial release
function b = randerr (n, m, err, seed)
switch (nargin)
case 0,
m = 1;
n = 1;
err = 1;
seed = Inf;
case 1,
m = n;
err = 1;
seed = Inf;
case 2,
err = 1;
seed = Inf;
case 3,
seed = Inf;
case 4,
otherwise
usage ("b = randerr (n, [m, [err, [seed]]])");
endswitch
## Check error vector
[ar,ac] = size (err);
if (ac == 1)
if (ar > 1)
err = err';
endif
elseif ((ac > 1) && (ar != 1) && (ar != 2))
error ("randerr: err must be a scalar, vector or two row matrix");
endif
for i=1:ac
if (err(1,i) > m)
error ("randerr: illegal number of errors per row");
endif
end
# Use randsrc to calculate the number of errors per row
nerrs = randsrc (n, 1, err, seed);
# Now put to errors into place in the return matrix
b = zeros (n, m);
for i=1:n
if (nerrs(i) > 0)
if (nerrs(i) == 1)
indx = sort(randint(1,nerrs(i),m,seed));
else
do
indx = sort(randint(1,nerrs(i),m,seed));
until (! any(indx(1:nerrs(i)-1) == indx(2:nerrs(i))))
endif
b(i,indx+1) = ones(1,nerrs(i));
endif
end
endfunction
%!shared n, err1, err2, seed, a1, a2, a3, a4, a5, a6
%! n = 10; err1 = 2; err2 = [1,2;0.7,0.3] ; seed = 1;
%! a1 = randerr(n); a2 = randerr(n,n);
%! a3 = randerr(n,n,err1); a4 = randerr(n,n,err2);
%! a5 = randerr(n,n,err1,seed); a6 = randerr(n,n,err1,seed);
%!error randerr (n,n,n,n,n);
%!assert (size(a1) == [n, n] && size(a2) == [n, n]);
%!assert (all (sum (a1.') == 1) && all (sum (a2.') == 1))
%!assert (all((a1(:) == 1 | a1(:) == 0)) &&all((a2(:) == 1 | a2(:) == 0)))
%!assert (size(a3) == [n, n] && size(a4) == [n, n]);
%!assert (all (sum (a3.') == err1))
%!assert (all((a3(:) == 1 | a3(:) == 0)))
%!assert (all ((sum (a4.') == err2(1,1)) | (sum (a4.') == err2(1,2))))
%!assert (all((a4(:) == 1 | a4(:) == 0)))
%!assert (a5(:) == a6(:));
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