help me to reduce my function time runing

Hi every body

This is my code

if true
  for r = 1:100
  U = 1 * (r-1);
  for c = 1:100
  V = 2 * (c-1);
  F(r,c) = 10 * sin(U + V);
  end
  end
  imagesc(F);
  colormap(gray);

end

Its generate a replicate pattern which I upload it here. Is there any suggestion to reduce the running time for this code?

Thanks

Answer 1

[Roger Stafford]

   U = (0:99).';
   V = 0:2:198;
   F = (10*sin(U))*cos(V)+(10*cos(U))*sin(V);
   imagesc(F);
   colormap(gray);

Answer 2

[Henrik]

This should work:

if true
F=zeros(100,100); %always preallocate
c = 1:100;
V = 2 * (c-1);
for r = 1:100
U = 1 * (r-1);
F(r,:) = 10 * sin(U + V);
end
imagesc(F);
colormap(gray);
end

You can get rid of the r loop too with e.g. bsxfun, but I don't have time to test it right now

[mostafa]

your answer is true but if i change the size to 150*100 it wouldn't work.