Run script using a group of values?

Hi,

I am trying to do a sort of brute-force optimisation method on my script. I have 3 parameters, and I want to use 3 values for each of those 3 parameters.

I want to script to run with all possible values, giving a total of 27 results.

What is the best way of doing this? Should I just use 3 nested "for" loops?

Thanks

Answer 1

[Matt J]

You can generate a matrix with all combinations using ndgrid, e.g.,

[p1,p2,p3]=ndgrid(1:3,10:10:30,100:100:300 );

Combinations = [p1(:),p2(:),p3(:)]

Combinations = 27×3

1 10 100 2 10 100 3 10 100 1 20 100 2 20 100 3 20 100 1 30 100 2 30 100 3 30 100 1 10 200

Should I just use 3 nested "for" loops?

You could, or you could use a single loop over the rows of Combinations. Ideally, though, you would look for some vectorized way to process the entire Combinations matrix.

[TOK]

Thank you, this is something I wasn't aware of and will definitely be using!

I suppose I then have a single "for" loop for my whole script which then accesses the data using the indexing of the matrix?

[Matt J]

Yes, you could do that.

[TOK]

Thanks for your help with this Matt! In the end I just used nested for loops in my case, as it gave me the flexibility to specify a different number of values for each of my 3 parameters.