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1 ## Copyright (C) 2003 Shai Ayal |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, write to the Free |
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17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {[@var{c}, @var{lev}] =} contourc (@var{x}, @var{y}, @var{z}, @var{vn}) |
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22 ## Compute isolines (countour lines) of the matrix @var{z}. |
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23 ## Parameters @var{x}, @var{y} and @var{vn} are optional. |
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24 ## |
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25 ## The return value @var{lev} is a vector of the contour levels. |
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26 ## The return value @var{c} is a 2 by @var{n} matrix containing the |
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27 ## contour lines in the following format |
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28 ## |
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29 ## @example |
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30 ## @var{c} = [lev1, x1, x2, ..., levn, x1, x2, ... |
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31 ## len1, y1, y2, ..., lenn, y1, y2, ...] |
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32 ## @end example |
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33 ## |
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34 ## @noindent |
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35 ## in which contour line @var{n} has a level (height) of @var{levn} and |
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36 ## length of @var{lenn}. |
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37 ## |
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38 ## If @var{x} and @var{y} are omitted they are taken as the row/column |
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39 ## index of @var{z}. @var{vn} is either a scalar denoting the number of lines |
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40 ## to compute or a vector containing the values of the lines. If only one |
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41 ## value is wanted, set @code{@var{vn} = [val, val]}; |
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42 ## If @var{vn} is omitted it defaults to 10. |
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43 ## |
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44 ## For example, |
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45 ## @example |
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46 ## @group |
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47 ## x = 0:2; |
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48 ## y = x; |
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49 ## z = x' * y; |
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50 ## contourc (x, y, z, 2:3) |
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51 ## @result{} 2.0000 2.0000 1.0000 3.0000 1.5000 2.0000 |
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52 ## 2.0000 1.0000 2.0000 2.0000 2.0000 1.5000 |
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53 ## |
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54 ## @end group |
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55 ## @end example |
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56 ## @seealso{contour} |
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57 ## @end deftypefn |
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58 |
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59 ## Author: shaia |
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60 |
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61 function [c, lev] = contourc (varargin) |
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62 |
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63 if (nargin == 1) |
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64 vn = 10; |
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65 z = varargin{1}; |
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66 x = 1:size(z,2); |
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67 y = 1:size(z,1); |
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68 elseif (nargin == 2) |
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69 vn = varargin{2}; |
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70 z = varargin{1}; |
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71 x = 1:size(z,2); |
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72 y = 1:size(z,1); |
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73 elseif (nargin == 3) |
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74 vn = 10; |
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75 x = varargin{1}; |
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76 y = varargin{2}; |
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77 z = varargin{3}; |
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78 elseif (nargin == 4) |
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79 vn = varargin{4}; |
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80 x = varargin{1}; |
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81 y = varargin{2}; |
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82 z = varargin{3}; |
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83 else |
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84 print_usage (); |
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85 endif |
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86 |
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87 if (isscalar (vn)) |
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88 vv = linspace (min (z(:)), max (z(:)), vn+2)(2:end-1); |
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89 else |
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90 vv = unique (sort (vn)); |
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91 endif |
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92 |
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93 ## Vectorize the x,y vectors, assuming they are output from meshgrid. |
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94 if (! isvector (x)) |
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95 x = x(1,:); |
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96 endif |
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97 |
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98 if (! isvector (y)) |
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99 y = y(:,1); |
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100 endif |
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101 |
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102 ## Make everyone the right dimensions. |
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103 if (size (x, 2) == 1) |
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104 x = x'; |
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105 endif |
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106 if (size (y, 2) == 1) |
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107 y = y'; |
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108 endif |
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109 |
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110 ## Now call __contourc__ for the real work... |
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111 c=__contourc__(x,y,z,vv); |
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112 if nargout==2, |
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113 lev = vv; |
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114 endif |
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115 |
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116 endfunction |
