Example function of two variables

`Z = peaks;`

Z = peaks(n);

Z = peaks(V);

Z = peaks(X,Y);

peaks(...)

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

`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.