surf函數

surf函數可以繪製3d圖，調用格式爲surf(x,y,z,C)，其中x和y爲自變量，z爲關於x和y的函數，z以矩陣形式存在，C可以省略，默認情況下與z相同。
示例：

>>[x,y]=meshgrid(-3:.2:3,-2:.2:2);z=(x.^2-2*x).*exp(-x.^2-y.^2-x.*y);
>>surf(x,y,z)
>>surf(x,y,z,z-10)

雖然c爲z-10但我沒有發現有什麼變化 !!!∑(ﾟДﾟノ)ノ

MATLAB中的解釋爲

>> help surf
 SURF   3-D colored surface.
    SURF(X,Y,Z,C) plots the colored parametric surface 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.
    The shading model is set by SHADING.

    SURF(X,Y,Z) uses C = Z, so color is proportional to surface height.

    SURF(x,y,Z) and SURF(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 surface patches 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.

    SURF(Z) and SURF(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.

    SURF(...,'PropertyName',PropertyValue,...) sets the value of the
    specified surface property.  Multiple property values can be set
    with a single statement.

    SURF(AX,...) plots into AX instead of GCA.

    SURF returns a handle to a surface plot object.

    AXIS, CAXIS, COLORMAP, HOLD, SHADING and VIEW set figure, axes, and
    surface properties which affect the display of the surface.

    See also surfc, surfl, mesh, shading.

    Reference page in Help browser
       doc surf