There is an element of too many commands in scilab lets try to list
the ones we need.

*****
ode -- seems logical that we will need an ode command. The help page is
under "Optimization and simulation". The calling order is
	y = ode(y0, t0, t, f)
		y0 is the initial vector (or value)
		t0 is the initial time
		t is a row vector of times where the solution is computed
		f is the  function in the ode y' = f(t, y) [see function below]
We can decide the method the ode solver uses or let it default. Changes
are we will use either the default and/or 'rkf' 

*****
function -- (this is different from matlab which .m files) this is in line.
for example for the ode y' = t + y^2 we would use
	function ydot = f(t, y)
	ydot = t + y^2;
	endfunction
A more complex example from the system x' = -y, y' = x the "y" variable is
really the vector [x; y] = [ x ]
                           [ y ]
and our example function becomes
	function ydot = f(t, y)
	ydot = [-y(2,1),y(1,1)];
	endfunction


****
plot the function. The help page for plot is in the graphics library
help section. Warning there two separate plot systems you want the
new one which uses "plot" and not "plot2d" etc. Plots have too many
features.

### plot y = f(x)
	x = -1:0.1:1; // colon operator this makes x the vector
	-1, -0.9, -0.8, ... 0.8, 0.9, 1
	y = f(x) for example y = x .* x - 1 which make y
	0, -0.19, -0.26, ... -0.26, -0.19, 0
the command plot(x,y) will now plot x^2-1.

*** plot colors and markers (LineSpec help page)
plot(x,y,"rx") will plot the data with red crosses.
plot(x,y,"r-x") will plot the data with red crosses and connect the crosses.
"go" green circles, "b--" blue dotted lines, "kd" black diamonds, "y+"
yellow plus signs, "c." cyan points, "ms" magenta squares.

*** more plot commands add more to the graph. clf() clears the graph,
xgrid() adds a grid, xtitle("title", "x axis label", "y axis label")
adds some text. xs2eps(<window-number>,"foo.eps") saves the file to
a postscript file which can be printed or added to a word processor
document.

*** plot parametric x = x(t), y = y(t) use plot(x,y)  
	t = 0:0.1:2*%pi; // t goes from 0 to two pi.
	plot(cos(t),sin(t)); // a circle almost
	square(-1.2,-1.2,1.2,1.2); // make scale isometric

*** writing data