Summation with (Dependent summation)

I need to write a code in Matlab for the following equation:

Σ i=0 to 100 ( (f(x). Σ j=0 to k f(y) )

where f(x), f(y) and k returns constant values. I have tried to write this code. Kindly tell me if this code is logically correct or if we can avoid loops; it would be better.

fx=0.08092; 
fy=0.01932;
k=300
YY1 = [];
sum2=0;
for i=1:100
     Y2 = [];
    for j=1:k

            Y1=sum(f2);
      end
       Y2=sum(f1*Y1)
      YY1 = [YY1 Y2];
  end 
  Final=sum(YY1)

Answer 1

[Sean de Wolski]

This line will slow it down a lot:

YY1 = [YY1 Y1];

It resizes YY! on each iteration. Instead, rpeallocate YY1 and then fill it in:

YY1 = zeros(100*jj,1);

then

YY1(ii+jj-1) = Y1;

Of course if you don't need YY1 for anything other than the sum, then just add it on each iteration:

YY1 = YY1+Y1;

Also, your function is not dependent on the for loop variables, so the same answer will be returned on each iteration. This you could also just multiple

sum2 = sum(fx*sum(fy))*100*jj

Answer 2

[Usman Khalid]

Thanks for your answer. Please tell me why did you write jj instead of j? and there is another error at YY1(ii+jj-1) = Y1; Error: Attempted to access YY1(-1); index must be a positive integer or logical