diff scripts/plot/contourc.m @ 6257:44c91c5dfe1d

[project @ 2007-01-30 19:16:52 by jwe]
author jwe
date Tue, 30 Jan 2007 19:16:55 +0000
parents
children 2f357df626cb
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/plot/contourc.m	Tue Jan 30 19:16:55 2007 +0000
@@ -0,0 +1,105 @@
+## Copyright (C) 2003 Shai Ayal
+##
+## 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, or (at your option)
+## any later version.
+##
+## OctPlot 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 OctPlot; see the file COPYING.  If not, write to the Free
+## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+## 02111-1307, USA.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} [@var{c}, @var{lev}] =  contourc (@var{x}, @var{y}, @var{z}, @var{vv})
+## Compute isolines (countour lines) of the matrix @var{z}. 
+## Parameters @var{x}, @var{y} and @var{vn} are optional.
+##
+## The return value @var{lev} is a vector of the contour levels.
+## The return value @var{c} is a 2 by @var{n} matrix containing the
+## contour lines in the following format
+##
+## @example
+## @var{c} = [lev1 , x1 , x2 , ... , levn , x1 , x2 , ... 
+##      len1   , y1 , y2 , ... , lenn   , y1 , y2 , ...  ]
+## @end example
+##
+## @noindent
+## in which contour line @var{n} has a level (height) of @var{levn} and
+## length of @var{lenn}.
+## 
+## If @var{x} and @var{y} are omitted they are taken as the row/column 
+## index of @var{z}.  @var{vn} is either a scalar denoting the number of lines 
+## to compute or a vector containing the values of the lines. If only one 
+## value is wanted, set @code{@var{vn} = [val, val]};
+## If @var{vn} is omitted it defaults to 10.
+##
+## @example
+## @var{c}=contourc (@var{x}, @var{y}, @var{z}, linspace(0,2*pi,10))
+## @end example
+## @seealso{contour}
+## @end deftypefn
+
+## Author: shaia
+
+function [c, lev] = contourc (varargin)
+
+  if (nargin == 1)
+    vn = 10;
+    z = varargin{1};
+    x = 1:size(z,1);
+    y = 1:size(z,2);
+  elseif (nargin == 2)
+    vn = varargin{2};
+    z = varargin{1};
+    x = 1:size(z,1);
+    y = 1:size(z,2);
+  elseif (nargin == 3)
+    vn = 10;
+    x = varargin{1};
+    y = varargin{2};
+    z = varargin{3};
+  elseif (nargin == 4)
+    vn = varargin{4};
+    x = varargin{1};
+    y = varargin{2};
+    z = varargin{3};
+  else
+    print_usage ();
+  endif
+
+  if (isscalar (vn))
+    vv = linspace (min (z(:)), max (z(:)), vn+2)(2:end-1);
+  else
+    vv = unique (sort (vn));
+  endif
+
+  ## Vectorize the x,y vectors, assuming they are output from meshgrid.
+  if (! isvector (x))
+    x = x(1,:);
+  endif
+
+  if (! isvector (y))
+    y = y(:,1);
+  endif
+
+  ## Make everyone the right dimensions.
+  if (size (x, 2) == 1)
+    x = x';
+  endif
+  if (size (y, 2) == 1)
+    y = y';
+  endif
+
+  ## Now call __contourc__ for the real work...
+  c=__contourc__(x,y,z,vv);
+  if nargout==2,
+    lev = vv;
+  endif
+
+endfunction