Using mod output to isolate variables

Question

I am not sure I am using the correct terms here, I will try to be descriptive.

I want to isolate (or control for) selected variables. That is, from a dataset (x,y,z,result) to create a model and then plot (x,result) considering y,z to be fixed. The final plot will be extrapolated to a wider range of x values.
I am at the point of having the model created (I used linear regression for testing purposes). The remaining steps, which I can't find out how to perform, are to create the appropriate dataset and apply the model.
Is there a data generator suitable for that or should I manually create the tables like (1,0,0),(2,0,0),(3,0,0),(4,0,0)... ?
After data is entered, or generated, how do I use the "mod" output to predict the result value?

Finally, am I using a totally wrong approach for the task I am trying to achieve? Is there a better way to visualize that kind of dependancy than this one?

Thank you all in advance.

iason · Answer

Actually the exact form of a(r,t), b(r,t), c(r,t) is not known. But it is not needed.
A visual representation of mes vs res for 4-5 pairs of (r,t) would be enough.
Still, is it reasonable to ask for enough data values with the same t and r? Gathering 100 examples for each pair will take around 8 months.
And then I could train the model 5 times and get the required 5 values for a,b,c.
I was hoping I could find a workaround and work with randomly collected values but it seems quite difficult.

wessel · Answer

And what is the form of a(t,r), b(t,r) and c(t,r)?

This does not seem like a problem suitable for Rapid Miner.

You can use a fuzzy neural network, or a genetic algorithm to solve this problem.
But you will have to write your own Java code.

Best regards,

Wessel

iason · Answer

Thank you again for replying. Your help is very much appreciated.

The problem is that with mes=f(res)=a*res^2 + b*res + c the values of a,b,c are not independent of t,r.
Doing that kind of regression would only acounf for c=g(t,r).
What I want to do is find a and b, given the values of t,r.
To put it in a proper form, the function is:

mes(res, t, r) = a(t,r)*res^2 + b(t,r)*res + c(t,r)

The quest is to find a(t,r), b(t,r) and c(t,r).