Matlab程序：二元函数空间曲面

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1. function h = mesh(x,y,z,c)
   
2. %空间曲面图
   
3. %  mesh(x,y,z)其中x,y,z为同阶矩阵，每一组对应元素代表一个网格点。
   
4. %
   
5. %例如 曲面 z=x.*exp(-x^2-y^2),-2<x<2,-2<y<2。
   
6. %
   
7. %     clear;close;xa=-2:.2:2;ya=xa;
   
8. %     [x,y]=meshgrid(xa,ya);z=x.*exp(-x.^2-y.^2);
   
9. %     mesh(x,y,z);%网格图
   
10. %
    
11. %MESH   3-D mesh surface.
    
12. %   MESH(X,Y,Z,C) plots the colored parametric mesh defined by
    
13. %   four matrix arguments.  The view point is specified by VIEW.
    
14. %   The axis labels are determined by the range of X, Y and Z,
    
15. %   or by the current setting of AXIS.  The color scaling is determined
    
16. %   by the range of C, or by the current setting of CAXIS.  The scaled
    
17. %   color values are used as indices into the current COLORMAP.
    
18. %
    
19. %   MESH(X,Y,Z) uses C = Z, so color is proportional to mesh height.
    
20. %
    
21. %   MESH(x,y,Z) and MESH(x,y,Z,C), with two vector arguments replacing
    
22. %   the first two matrix arguments, must have length(x) = n and
    
23. %   length(y) = m where [m,n] = size(Z).  In this case, the vertices
    
24. %   of the mesh lines are the triples (x(j), y(i), Z(i,j)).
    
25. %   Note that x corresponds to the columns of Z and y corresponds to
    
26. %   the rows.
    
27. %
    
28. %   MESH(Z) and MESH(Z,C) use x = 1:n and y = 1:m.  In this case,
    
29. %   the height, Z, is a single-valued function, defined over a
    
30. %   geometrically rectangular grid.
    
31. %
    
32. %   MESH returns a handle to a SURFACE object.
    
33. %
    
34. %   AXIS, CAXIS, COLORMAP, HOLD, SHADING and VIEW set figure, axes, and
    
35. %   surface properties which affect the display of the mesh.
    
36. %
    
37. %   See also SURF, MESHC, MESHZ, WATERFALL.
    
38. 
    
39. %-------------------------------
    
40. %   Additional details:
    
41. %
    
42. %   MESH sets the FaceColor property to background color and the EdgeColor
    
43. %   property to 'flat'.
    
44. %
    
45. %   If the NextPlot axis property is REPLACE (HOLD is off), MESH resets
    
46. %   all axis properties, except Position, to their default values
    
47. %   and deletes all axis children (line, patch, surf, image, and
    
48. %   text objects).
    
49. 
    
50. %   Copyright (c) 1984-98 by The MathWorks, Inc.
    
51. %   $Revision: 5.7 $  $Date: 1997/11/21 23:33:57 $
    
52. 
    
53. %   J.N. Little 1-5-92
    
54. %   Modified 2-3-92, LS.
    
55. 
    
56. user_view = 0;
    
57. cax = newplot;
    
58. fc = get(gca,'color');
    
59. if strcmp(lower(fc),'none')
    
60.     fc = get(gcf,'color');
    
61. end
    
62. 
    
63. if nargin == 1
    
64.     hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
65. elseif nargin == 2
    
66.         if isstr(y), error('Invalid argument.'); end
    
67.     [my ny] = size(y);
    
68.     [mx nx] = size(x);
    
69.     if mx == my & nx == ny
    
70.         hh = surface(x,y,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
71.     else
    
72.         if my*ny == 2 % must be [az el]
    
73.             hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
74.             set(gca,'View',y);
    
75.             user_view = 1;
    
76.         else
    
77.             error('Invalid input arguments.');
    
78.         end
    
79.     end
    
80. elseif nargin == 3
    
81.         if isstr(y) | isstr(z), error('Invalid argument.'); end
    
82.     if min(size(y)) == 1 & min(size(z)) == 1 % old style
    
83.         hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
84.         set(gca,'View',y);
    
85.         user_view = 1;
    
86.     else
    
87.         hh = surface(x,y,z,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
88.     end
    
89. elseif nargin == 4
    
90.     hh = surface(x,y,z,c,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');
    
91. else
    
92.     error('Requires 1, 2, 3, or 4 input arguments.');
    
93. end
    
94. if ~ishold & ~user_view
    
95.     view(3); grid on
    
96. end
    
97. if nargout == 1
    
98.     h = hh;
    
99. end
    

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