if you really just want to draw a graph using your stored values in your arrays..

use something like this

stroke(0);
noFill();
beginShape();
for(int i = 0; i<array.length;i++){
vertex(arrayX[i],arrayY[i]);
}
endShape();

depending on your values it might be useful to use map() to map them to your screen coordinates.

Yes, you can do that, have a look at the ScatterPlot example included in the library. Depending on how you want to draw the data this might not be exactly what you need but it shows how to handle data points rather than equations.

I guess we should include a dedicated 'load and plot 2D data' example in the next version.

Andreas

thx for the replies.  I will try it out and see what happens.  

hi I have done what you said  cedrickiefer but the graph plotted seems to be up side down.  

ok got it using popmatrix

did you get the result you were looking for ?