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1 ## Copyright (C) 1996, 1997 John W. Eaton |
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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, 59 Temple Place - Suite 330, Boston, MA |
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18 ## 02111-1307, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} contour (@var{z}, @var{n}, @var{x}, @var{y}) |
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22 ## Make a contour plot of the three-dimensional surface described by |
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23 ## @var{z}. Someone needs to improve @code{gnuplot}'s contour routines |
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24 ## before this will be very useful. |
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25 ## @end deftypefn |
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26 ## @seealso{plot, semilogx, semilogy, loglog, polar, mesh, contour, |
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27 ## bar, stairs, gplot, gsplot, replot, xlabel, ylabel, and title} |
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28 |
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29 ## Author: jwe |
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30 |
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31 function contour (z, n, x, y) |
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32 |
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33 if (nargin == 1) |
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34 n = 10; |
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35 endif |
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36 |
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37 ## XXX FIXME XXX -- these plot states should really just be set |
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38 ## temporarily, probably inside an unwind_protect block, but there is |
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39 ## no way to determine their current values. |
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40 |
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41 if (nargin == 1 || nargin == 2) |
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42 if (is_matrix (z)) |
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43 gset nosurface; |
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44 gset contour; |
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45 gset cntrparam bspline; |
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46 if (is_scalar (n)) |
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47 command = sprintf ("gset cntrparam levels %d", n); |
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48 elseif (is_vector (n)) |
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49 tmp = sprintf ("%f", n(1)); |
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50 for i = 2:length (n) |
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51 tmp = sprintf ("%s, %f", tmp, n(i)); |
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52 endfor |
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53 command = sprintf ("gset cntrparam levels discrete %s", tmp); |
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54 endif |
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55 eval (command); |
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56 gset noparametric; |
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57 gset view 0, 0, 1, 1; |
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58 gsplot z w l 1; |
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59 else |
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60 error ("contour: argument must be a matrix"); |
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61 endif |
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62 elseif (nargin == 4) |
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63 if (is_vector (x) && is_vector (y) && is_matrix (z)) |
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64 xlen = length (x); |
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65 ylen = length (y); |
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66 if (xlen == rows (z) && ylen == columns (z)) |
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67 if (rows (x) == 1) |
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68 x = x'; |
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69 endif |
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70 len = 3 * ylen; |
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71 zz = zeros (xlen, len); |
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72 k = 1; |
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73 for i = 1:3:len |
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74 zz(:,i) = x; |
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75 zz(:,i+1) = y(k) * ones (xlen, 1); |
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76 zz(:,i+2) = z(:,k); |
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77 k++; |
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78 endfor |
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79 gset nosurface; |
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80 gset contour; |
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81 gset cntrparam bspline; |
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82 if (is_scalar (n)) |
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83 command = sprintf ("gset cntrparam levels %d", n); |
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84 elseif (is_vector (n)) |
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85 tmp = sprintf ("%f", n(1)); |
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86 for i = 2:length (n) |
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87 tmp = sprintf ("%s, %f", tmp, n(i)); |
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88 endfor |
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89 command = sprintf ("gset cntrparam levels discrete %s", tmp); |
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90 endif |
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91 eval (command); |
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92 gset parametric; |
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93 gset view 0, 0, 1, 1; |
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94 gsplot zz w l 1; |
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95 else |
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96 msg = "contour: rows (z) must be the same as length (x) and"; |
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97 msg = sprintf ("%s\ncolumns (z) must be the same as length (y)", msg); |
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98 error (msg); |
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99 endif |
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100 else |
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101 error ("contour: x and y must be vectors and z must be a matrix"); |
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102 endif |
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103 else |
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104 usage ("contour (z, levels, x, y)"); |
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105 endif |
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106 |
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107 endfunction |
