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# peaks

Example function of two variables

## Syntax

Z = peaks;
Z = peaks(n);
Z = peaks(V);
Z = peaks(X,Y);
peaks(...)
[X,Y,Z] = peaks(...);

## Description

peaks is a function of two variables, obtained by translating and scaling Gaussian distributions, which is useful for demonstrating mesh, surf, pcolor, contour, and so on.

Z = peaks; returns a 49-by-49 matrix.

Z = peaks(n); returns an n-by-n matrix.

Z = peaks(V); returns an n-by-n matrix, where n = length(V).

Z = peaks(X,Y); evaluates peaks at the given X and Y (which must be the same size) and returns a matrix the same size.

peaks(...) (with no output argument) plots the peaks function with surf. Use any of the input argument combinations in the previous syntaxes.

[X,Y,Z] = peaks(...); returns two additional matrices, X and Y, for parametric plots, for example, 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.

## Examples

expand all

### Peaks Surface

Create a 5-by-5 matrix of peaks and display the surface.

```figure
peaks(5);
```
```
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)

```