fplot3d1 3D gray or color level plot of a surface defined by a function

## Syntax

    fplot3d1(xr,yr,f,[theta,alpha,leg,flag,ebox])
                fplot3d1(xr,yr,f,<opt_args>)

## Arguments

xr

  row vector of size n1.

yr

  row vector of size n2.

f

  external of type z=f(x,y).

theta,alpha,leg,flag,ebox

  see `plot3d1`.

<opt_args>

  see `plot3d`.

## Description

`fplot3d1` plots a 3D gray or color level plot of a surface defined by the external function `f` on the grid defined by `xr` and `yr`.

Enter the command `fplot3d1()` to see a demo.

## Examples

    deff('z=f(x,y)','z=x^4-y^4')
    x=-3:0.2:3 ;y=x ;
    clf() ;fplot3d1(x,y,f,alpha=5,theta=31)

deff('z=f(x,y)','z=x^4-y^4') x=-3:0.2:3 ;y=x ; clf() ;fplot3d1(x,y,f,alpha=5,theta=31)

## See also

- plot3d1