Store function results from for loop

This is a project for a class.

Three variables d_o_shaft, h and w are the inputs.

Two outputs are Defl and Nf.

I'd like to store the three inputs in a 3xn matrix every time they meet a certain criteria; 1.3 <= Nf < 1.31 and Defl < .01.

This is the basic structure of my code, I simplified the equations for visual ease.

for do_shaft = .04:.001:.14

for h = .01:.001:.10

for w = .01:.001:.10

Nf = func(inputs)

Defl = func(inputs)

end

end

end

Answer 1

[Torsten]

i = 0;
for do_shaft = .04:.001:.14
  for h = .01:.001:.10
    for w = .01:.001:.10            
      Nf = func(inputs)
      Defl = func(inputs)
      if Nf >= 1.3 && Nf <= 1.31 && Defl <= 0.01
        i = i + 1;
        matrix(1:3,i) =[do_shaft,h,w]
      end
    end
  end
end

[Nicolas Caride]

Thanks for the input! I don't see that result in the workspace on the right- how can I access that matrix to see what kind of results I get?

[Torsten]

Sorry, should be:

matrix(i,1:3) = [do_shaft,h,w]

instead of

matrix(1:3,i) = [do_shaft,h,w]

You can inspect the matrix after the loop.

[Voss]

@Nicolas Caride It is a good idea to initialize matrix to empty before the loop (as in my answer), especially if you are running this in the base workspace. For instance, if the conditions are never met, matrix will be whatever it was before you ran this code, which may be something completely unrelated or it may not exist at all. In general, without initializing first, you're attempting to add a column (or row) to a matrix that may be the wrong size, in which case you'll run into an error.

[Nicolas Caride]

Thanks so much for the help. That was exactly what I needed.

Answer 2

[Voss]

matrix = [];
for do_shaft = .04:.001:.14
    for h = .01:.001:.10
        for w = .01:.001:.10 
            Nf = func(inputs);
            Defl = func(inputs);
            if Nf >= 1.3 && Nf < 1.31 && Defl < 0.01
                matrix(:,end+1) = [do_shaft; h; w];
            end
        end
    end
end