数学建模必备

%空间曲线图

% PLOT3(x,y,z,s)其中x,y,z为向量，每一组分量代表一个数据点。

%                    s为表示颜色、连线和标记选择的字符串

%例如 曲线x=exp(-0.2*z)*cos(0.5*pi*z),y=exp(-0.2*z)*sin(0.5*pi*z), 0<z<20。

%

%  clear;close;z=0:0.1:20;r=exp(-0.2*z);th=0.5*pi*z;

%  x=r.*cos(th);y=r.*sin(th);plot3(x,y,z,'r');

%

%PLOT3  Plot lines and points in 3-D space.

%   PLOT3() is a three-dimensional analogue of PLOT().

% 

%   PLOT3(x,y,z), where x, y and z are three vectors of the same length,

%   plots a line in 3-space through the points whose coordinates are the

%   elements of x, y and z.

% 

%   PLOT3(X,Y,Z), where X, Y and Z are three matrices of the same size,

%   plots several lines obtained from the columns of X, Y and Z.

% 

%   Various line types, plot symbols and colors may be obtained with

%   PLOT3(X,Y,Z,s) where s is a 1, 2 or 3 character string made from

%   the characters listed under the PLOT command.

% 

%   PLOT3(x1,y1,z1,s1,x2,y2,z2,s2,x3,y3,z3,s3,...) combines the plots

%   defined by the (x,y,z,s) fourtuples, where the x's, y's and z's are

%   vectors or matrices and the s's are strings.

% 

%   Example: A helix:

% 

%       t = 0:pi/50:10*pi;

%       plot3(sin(t),cos(t),t);

% 

%   PLOT3 returns a column vector of handles to LINE objects, one

%   handle per line. The X,Y,Z triples, or X,Y,Z,S quads, can be 

%   followed by parameter/value pairs to specify additional 

%   properties of the lines.

%

%   See also PLOT, LINE, AXIS, VIEW, MESH, SURF.



%-------------------------------

%   Additional details:

%

%

%   If the NextPlot axis property is REPLACE (HOLD is off), PLOT3 resets 

%   all axis properties, except Position, to their default values, and

%   deletes all axis children (line, patch, text, surface, and

%   image objects).



%   Copyright (c) 1984-98 by The MathWorks, Inc.

%   $Revision: 5.3 $  $Date: 1997/11/21 23:34:01 $

%   Built-in function.

%二维图（一元函数图）

%用法 plot(x,y,s) 其中x,y为向量，每一对分量代表一个数据点。

%                    s为表示颜色、连线和标记选择的字符串

%图形的线型，标记，颜色均可设定，常用有

%       颜色           |                线型                        标记

% ---------------------      -------------------  -------------------

%   b          蓝(默认)               -      实线(默认)        无(默认)

%   g           绿             --     虚线         *          星

%   r           红             :      粗点线       .          点

%   y           黄             -.     点划线       o          圈

%   m           洋红                               x          叉

%   c           青                                 +          十字

%   w           白                                 s          方块

%   k           黑                                 d          菱形

%                                                  v          下三角形

%                                                  ^          上三角形

%                                                  <          左三角形

%                                                  >          右三角形

%                                                  h          六角形

%                                                  p          五角形

%例如

%    x=0:0.2:2*pi;y=sin(x);

%    plot(x,y,'r*')

%

%PLOT   Linear plot. 

%   PLOT(X,Y) plots vector Y versus vector X. If X or Y is a matrix,

%   then the vector is plotted versus the rows or columns of the matrix,

%   whichever line up. 

%

%   PLOT(Y) plots the columns of Y versus their index.

%   If Y is complex, PLOT(Y) is equivalent to PLOT(real(Y),imag(Y)).

%   In all other uses of PLOT, the imaginary part is ignored.

%

%   Various line types, plot symbols and colors may be obtained with

%   PLOT(X,Y,S) where S is a character string made from one element

%   from any or all the following 3 colunms:

%

%          y     yellow        .     point              -     solid

%          m     magenta       o     circle             :     dotted

%          c     cyan          x     x-mark             -.    dashdot 

%          r     red           +     plus               --    dashed   

%          g     green         *     star

%          b     blue          s     square

%          w     white         d     diamond

%          k     black         v     triangle (down)

%                              ^     triangle (up)

%                              <     triangle (left)

%                              >     triangle (right)

%                              p     pentagram

%                              h     hexagram

%                         

%   For example, PLOT(X,Y,'c+:') plots a cyan dotted line with a plus 

%   at each data point; PLOT(X,Y,'bd') plots blue diamond at each data 

%   point but does not draw any line.

%

%   PLOT(X1,Y1,S1,X2,Y2,S2,X3,Y3,S3,...) combines the plots defined by

%   the (X,Y,S) triples, where the X's and Y's are vectors or matrices 

%   and the S's are strings.  

%

%   For example, PLOT(X,Y,'y-',X,Y,'go') plots the data twice, with a

%   solid yellow line interpolating green circles at the data points.

%

%   The PLOT command, if no color is specified, makes automatic use of

%   the colors specified by the axes ColorOrder property.  The default

%   ColorOrder is listed in the table above for color systems where the

%   default is yellow for one line, and for multiple lines, to cycle

%   through the first six colors in the table.  For monochrome systems,

%   PLOT cycles over the axes LineStyleOrder property.

%

%   PLOT returns a column vector of handles to LINE objects, one

%   handle per line. 

%

%   The X,Y pairs, or X,Y,S triples, can be followed by 

%   parameter/value pairs to specify additional properties 

%   of the lines.

%                                   

%   See also SEMILOGX, SEMILOGY, LOGLOG, GRID, CLF, CLC, TITLE,

%   XLABEL, YLABEL, AXIS, AXES, HOLD, COLORDEF, and SUBPLOT.



%   If the NextPlot axes property is "replace" (HOLD is off), PLOT resets 

%   all axes properties, except Position, to their default values,

%   deletes all axes children (line, patch, text, surface, and

%   image objects), and sets the View property to [0 90].



%   Copyright (c) 1984-98 by The MathWorks, Inc.

%   $Revision: 5.7 $  $Date: 1997/11/21 23:33:07 $

%   Built-in function.

function h = mesh(x,y,z,c)

%空间曲面图

%  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。

%

%例如 曲面 z=x.*exp(-x^2-y^2),-2<x<2,-2<y<2。

%

%     clear;close;xa=-2:.2:2;ya=xa;

%     [x,y]=meshgrid(xa,ya);z=x.*exp(-x.^2-y.^2);

%     mesh(x,y,z);%网格图

%

%MESH   3-D mesh surface.

%   MESH(X,Y,Z,C) plots the colored parametric mesh defined by

%   four matrix arguments.  The view point is specified by VIEW.

%   The axis labels are determined by the range of X, Y and Z,

%   or by the current setting of AXIS.  The color scaling is determined

%   by the range of C, or by the current setting of CAXIS.  The scaled

%   color values are used as indices into the current COLORMAP.

%

%   MESH(X,Y,Z) uses C = Z, so color is proportional to mesh height.

%

%   MESH(x,y,Z) and MESH(x,y,Z,C), with two vector arguments replacing

%   the first two matrix arguments, must have length(x) = n and

%   length(y) = m where [m,n] = size(Z).  In this case, the vertices

%   of the mesh lines are the triples (x(j), y(i), Z(i,j)).

%   Note that x corresponds to the columns of Z and y corresponds to

%   the rows.

%

%   MESH(Z) and MESH(Z,C) use x = 1:n and y = 1:m.  In this case,

%   the height, Z, is a single-valued function, defined over a

%   geometrically rectangular grid.

%

%   MESH returns a handle to a SURFACE object.

%

%   AXIS, CAXIS, COLORMAP, HOLD, SHADING and VIEW set figure, axes, and 

%   surface properties which affect the display of the mesh.

%

%   See also SURF, MESHC, MESHZ, WATERFALL.



%-------------------------------

%   Additional details:

%

%   MESH sets the FaceColor property to background color and the EdgeColor

%   property to 'flat'.

%

%   If the NextPlot axis property is REPLACE (HOLD is off), MESH resets 

%   all axis properties, except Position, to their default values

%   and deletes all axis children (line, patch, surf, image, and 

%   text objects).



%   Copyright (c) 1984-98 by The MathWorks, Inc.

%   $Revision: 5.7 $  $Date: 1997/11/21 23:33:57 $



%   J.N. Little 1-5-92

%   Modified 2-3-92, LS.



user_view = 0;

cax = newplot;

fc = get(gca,'color');

if strcmp(lower(fc),'none')

    fc = get(gcf,'color');

end



if nargin == 1

    hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

elseif nargin == 2

        if isstr(y), error('Invalid argument.'); end

    [my ny] = size(y);

    [mx nx] = size(x);

    if mx == my & nx == ny

        hh = surface(x,y,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

    else

        if my*ny == 2 % must be [az el]

            hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

            set(gca,'View',y);

            user_view = 1;

        else

            error('Invalid input arguments.');

        end

    end

elseif nargin == 3

        if isstr(y) | isstr(z), error('Invalid argument.'); end

    if min(size(y)) == 1 & min(size(z)) == 1 % old style

        hh = surface(x,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

        set(gca,'View',y);

        user_view = 1;

    else

        hh = surface(x,y,z,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

    end

elseif nargin == 4

    hh = surface(x,y,z,c,'FaceColor',fc,'EdgeColor','flat', 'FaceLighting', 'none', 'EdgeLighting', 'flat');

else

    error('Requires 1, 2, 3, or 4 input arguments.');

end

if ~ishold & ~user_view

    view(3); grid on

end

if nargout == 1

    h = hh;

end