Scilab Function
Last update : April 1993

artest - arnold dynamical system

### Calling Sequence

  `artest(f_l,[odem,xdim,npts])`
  `arnold(t,x)`
  `iarf([a])`

### Parameters

- `f_l`: can be "arnold" or arnold. It is the name of the external for the arnold system. If `f_l` is set to "arnold" a Fortran coded version of the arnold system where a(1:6)=1 will be used and if `f_l` is set to arnold a Scilab coded version will be used . `arnold` is a Scilab macro coding the Arnold system. This macro is loaded when calling `artest`.
- `iarf`: is used to fix the values of `a` in the Scilab coded case. `a` is a vector of size 6.
- `odem,xdim,npts`: are optional arguments. Their meaning and syntax can be found in the `portr3d` help

### Description

A call to the function `artest()` will interactively display a phase portrait of a the following dynamical system :

          ydot(1)=a(1)*cos(y(2)) +a(2)*sin(y(3))
          ydot(2)=a(3)*cos(y(3)) +a(4)*sin(y(1))
          ydot(3)=a(5)*cos(y(1)) +a(6)*sin(y(2))

### See Also

`portr3d`, `ode`, `chaintest`, `lotest`,