为了方便测试立体绘图，MATLAB提供了一个peaks函数，可产生一个凹凸有致的曲面，包含了三个局部极大点及三个局部极小点，其方程式为：
要画出此函数的最快方法即是直接键入
peaks：
z = 3*(1-x).^2.*exp(-(x.^2) – (y+1).^2) …
– 10*(x/5 – x.^3 – y.^5).*exp(-x.^2-y.^2) …
– 1/3*exp(-(x+1).^2 – y.^2)
我们亦可对peaks函数取点，再以各种不同方法进行绘图。
——————————————————————-
MATLAB中的帮助信息：
PEAKS A sample function of two variables.
PEAKS is a function of two variables, obtained by translating and
scaling Gaussian distributions, which is useful for demonstrating
MESH, SURF, PCOLOR, CONTOUR, etc.
There are several variants of the calling sequence:
Z = PEAKS;
Z = PEAKS(N);
Z = PEAKS(V);
Z = PEAKS(X,Y);
PEAKS;
PEAKS(N);
PEAKS(V);
PEAKS(X,Y);
[X,Y,Z] = PEAKS;
[X,Y,Z] = PEAKS(N);
[X,Y,Z] = PEAKS(V);
The first variant produces a 49-by-49 matrix.
The second variant produces an N-by-N matrix.
The third variant produces an N-by-N matrix where N = length(V).
The fourth variant evaluates the function at the given X and Y,
which must be the same size. The resulting Z is also that size.
The next four variants, with no output arguments, do a SURF
plot of the result.
The last three variants also produce two matrices, X and Y, for
use in commands such as PCOLOR(X,Y,Z) or SURF(X,Y,Z,DEL2(Z)).
If not given as input, the underlying matrices X and Y are
[X,Y] = MESHGRID(V,V)
where V is a given vector, or V is a vector of length N with
elements equally spaced from -3 to 3. If no input argument is
given, the default N is 49.
Reference page in Help browser
doc peaks
z = 3*(1-x).^2.*exp(-(x.^2) - (y+1).^2) ...
- 10*(x/5 - x.^3 - y.^5).*exp(-x.^2-y.^2) ...
- 1/3*exp(-(x+1).^2 - y.^2)