** 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. **

** **