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.