Storing the results from nested loop

Hello, I have reviewed other posts and videos on this but those solutions did not work - well, not elegantly. How do I store each iteration of the following nested loop?

for a=0:3
  A= 2*a
  for b=a+1:6
      B=3*b
      for c=b+1:10
          C=4*c
          vec=[A B C]  % to store output of each iteration
      end
      plot(vec,'r--') % plot each iteration in its entirety, each time
  end
end

Answer 1

[KSSV]

count = 0 ;
vec = zeros([],3) ;
for a=0:3
    A= 2*a ;
    for b=a+1:6 
        B=3*b ;
        for c=b+1:10
            count = count+1 ;
            C=4*c ;
            vec(count,:)=[A B C] ;  % to store output of each iteration
        end
        plot(vec(count,:),'r--') % plot each iteration in its entirety, each time
    end
end

[Guillaume]

I think this needs a

figure;
hold on;

before the first loop to avoid overwriting each plot at each iteration.

[Pit Probst]

thanks both!

KSSV, to retrieve the values of a,b,c for which the sum maximum. And plot the calcuated A,B,C up to these values on a,b,c. How could I do that?

 %
  count = 0 ;
vec = zeros([],3) ;
for a=0:3
    A= 2*a ;
    for b=a+1:6 
        B=3*b ;
        for c=b+1:10
            C=4*c ;
            count = count+1 ;
            vec(count,:)=sum([A B C]) ;  
        end
        max(vec) % what were the values of a, b,c for this 
        % plot 
    end
end

Answer 2

[Guillaume]

You could of course not bother with the loops at all:

a = 0:3;
b = a(1)+1:6;  %too many elements, the extra will be removed later
c = b(1)+1:10; %too many elements, the extra will be removed later
[A, B, C] = ndgrid(a, b, c);
abc = [A(:), B(:), C(:)];
%now remove unwanted entries
abc(abc(:, 2) <= abc(:, 1) | abc(:, 3) <= abc(:, 2), :) = [];
%calculate vec and plot all
vec = abc .* [2 3 4];  
plot([1 2 3], vec, 'r--');

[Pit Probst]

Im coding an optimization. compared with KSSV and my own code, yours gives a slightly different answer - might be the actual right answer too but ill check on it. thanks for the vectorized format!

[Guillaume]

The orders of the rows is different, but I'm assuming it does not matter. If it does, at the end:

vec = sortrows(vec);