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[CreaPhase.git] / octave_packages / m / sparse / sprand.m

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+## Copyright (C) 2004-2012 Paul Kienzle
+##
+## This file is part of Octave.
+##
+## Octave 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.
+##
+## Octave 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 Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+##
+## Original version by Paul Kienzle distributed as free software in the
+## public domain.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} sprand (@var{m}, @var{n}, @var{d})
+## @deftypefnx {Function File} {} sprand (@var{s})
+## Generate a random sparse matrix.  The size of the matrix will be
+## @var{m} by @var{n}, with a density of values given by @var{d}.
+## @var{d} should be between 0 and 1.  Values will be uniformly
+## distributed between 0 and 1.
+##
+## If called with a single matrix argument, a random sparse matrix is
+## generated wherever the matrix @var{S} is non-zero.
+## @seealso{sprandn, sprandsym}
+## @end deftypefn
+
+## Author: Paul Kienzle <pkienzle@users.sf.net>
+##
+## Changelog:
+##
+## Piotr Krzyzanowski <przykry2004@users.sf.net>
+##      2004-09-27      use Paul's hint to allow larger random matrices
+##                      at the price of sometimes lower density than desired
+## David Bateman
+##      2004-10-20      Texinfo help and copyright message
+
+function S = sprand (m, n, d)
+
+  if (nargin == 1 )
+    S = __sprand_impl__ (m, @rand);
+  elseif ( nargin == 3)
+    S = __sprand_impl__ (m, n, d, "sprand", @rand);
+  else
+    print_usage ();
+  endif
+
+endfunction
+
+%!test
+%! s = sprand (4, 10, 0.1);
+%! assert (size (s), [4, 10]);
+%! assert (nnz (s) / numel (s), 0.1);
+
+%% Test 1-input calling form
+%!test
+%! s = sprand (sparse ([1 2 3], [3 2 3], [2 2 2]));
+%! [i, j, v] = find (s);
+%! assert (sort (i), [1 2 3]');
+%! assert (sort (j), [2 3 3]');
+%! assert (all (v > 0 & v < 1));
+
+%% Test input validation
+%!error sprand ()
+%!error sprand (1, 2)
+%!error sprand (1, 2, 3, 4)
+%!error sprand (ones(3), 3, 0.5)
+%!error sprand (3.5, 3, 0.5)
+%!error sprand (0, 3, 0.5)
+%!error sprand (3, ones(3), 0.5)
+%!error sprand (3, 3.5, 0.5)
+%!error sprand (3, 0, 0.5)
+%!error sprand (3, 3, -1)
+%!error sprand (3, 3, 2)
+