Dynamic for loops?

So my question is a bit complicated so hopefully I will be able to describe it adequately. I currently have a function that takes in parameter values a, b, c, d and returns vectors x, y. I am plotting the results for a wide range of parametric combinations. For plotting reasons I need the user to be able to specify the order the for loops occur. This is because I want to produce figures that uses subplot to display graphs for all the plots of two of the variables in a single figure. I think it will make more sense if I write a short pseudo-code.

EXAMPLE:

a = [1,2]; 
b = [3,4,5];
c = [6,7,8];
d = [9,10,11,12];
XAXIS = ‘a’
YAXIS = ‘b’

for ci=1:length(c)
for di=1:length(d)
  CASE = 0;
  for ai=1:length(a)
  for bi=1:length(b)
    CASE = CASE+1
    [x,y] = myfunction(a(ai),b(bi),c(ci),d(di));

      figure(1)
      subplot(length(a),length(b),CASE)
      plot(x,y)
  end
  end
  %SOME CODE TO SAVE THE CURRENT GRAPH TO A FILE
end
end

So the above code would save 12 figures that each had a 2x3 grid of plots. Is there a way to generalize the above code so that the user can specify XAXIS and YAXIS and have those two variables be the last ones looped over? I tried to put the for statement inside an eval, but matlab refuses to run it because it doesn’t match up right with the end statements. I feel like I am not explaining this well and so I would be happy to provide additional details if wanted.

Answer 1

[Walter Roberson]

Create a cell array of the variables. Create a vector of order indices according to user input.

paramcell = {a, b, c, d};
paramlengths = cellfun(@length, paramcell);

order = randperm(4);     %except use user input to decide the order

vals = cell(1,4);
for idx1 = 1 : paramlengths(order(1))
 vals{order(1)} = paramcell{order(1)}(idx1);
 for idx2 = 1 : paramlengths(order(2))
   vals{order(2)} = paramcell{order(2)}(idx2);
   CASE = 0;
   for idx3 = 1 : paramlengths(order(3))
     vals{order(3)} = paramcell{order(3)}(idx3);
     for idx4 = 1 : paramlengths(order(4))
       vals{order(4)} = paramcell{order(4)}(idx4);
       CASE = CASE+1;
       [x, y] = myfunction( vals{:} );
       ...
     end
   end
 end
end