update packages

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

diff --git a/octave_packages/m/sparse/spy.m b/octave_packages/m/sparse/spy.m
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+## Copyright (C) 1998-2012 Andy Adler
+##
+## 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/>.
+
+## -*- texinfo -*-
+## @deftypefn  {Function File} {} spy (@var{x})
+## @deftypefnx {Function File} {} spy (@dots{}, @var{markersize})
+## @deftypefnx {Function File} {} spy (@dots{}, @var{line_spec})
+## Plot the sparsity pattern of the sparse matrix @var{x}.  If the argument
+## @var{markersize} is given as a scalar value, it is used to determine the
+## point size in the plot.  If the string @var{line_spec} is given it is
+## passed to @code{plot} and determines the appearance of the plot.
+## @seealso{plot}
+## @end deftypefn
+
+function spy (x, varargin)
+
+  if (nargin < 1)
+    print_usage ();
+  endif
+
+  markersize = NaN;
+  if (numel (x) < 1000)
+    line_spec = "*";
+  else
+    line_spec = ".";
+  endif
+  for i = 1:length (varargin)
+    if (ischar (varargin{i}))
+      if (length (varargin{i}) == 1)
+        line_spec = [line_spec, varargin{i}];
+      else
+        line_spec = varargin{i};
+      endif
+    elseif (isscalar (varargin{i}))
+      markersize = varargin{i};
+    else
+      error ("spy: expected markersize or linespec");
+    endif
+  endfor
+
+  [i, j, s] = find (x);
+  [m, n] = size (x);
+
+  if (isnan (markersize))
+    plot (j, i, line_spec);
+  else
+    plot (j, i, line_spec, "markersize", markersize);
+  endif
+
+  axis ([0, n+1, 0, m+1], "ij");
+
+endfunction
+
+
+%!demo
+%! clf;
+%! spy (sprand (10,10, 0.2));
+
+%% Mark graphical function as tested by demo block
+%!assert (1);