any fast funcitons to do this triple for loop?

I have this code. Is there any way to make it faster. My data is huge. Thanks. I am simple restoring everthing into vector instead of 3D array:

ii = 1
for z = 1:data_size(3)
 for y = 1:data_size(2)
  for x = 1:data_size(1)
    data_tmp(ii) = data(x,y,z);
    ii           = ii+1;
  end
 end
end

[Daniel Shub]

If your data is huge, you will definitely want to preallocate data_tmp.

Answer 1

[Daniel Shub]

I believe

data_tmp = data(:);

should work, although the collapsing across dimension might not perfectly match your loops.

Edit: A simple check

data = reshape(1:8, 2, 2, 2)
data_size = size(data);

ii = 1;
for z = 1:data_size(3)
 for y = 1:data_size(2)
  for x = 1:data_size(1)
    data_tmp(ii) = data(x,y,z);
    ii           = ii+1;
  end
 end
end

isequal(data_tmp, data(:))

reveals that my solution does not match your solution. But,

isequal(data_tmp, data(:)')

does match. So the answer is

data_tmp = data(:)';

[jenka]

what do you mean: "collapsing across dimension might not perfectly match your loops"?

It is essential for my goal that the things are stored into my vector the way I put them through my loop (i.e. x first, then y, then z). Also, my starting point should be lower left corner. So I need some flipping?

[Daniel Shub]

See my edit.