out of memory error

I am facing a continuous out of memory error and I am wondering if these codes can be modified to avoid it:where RG,PC,and Acr are 6000x14771 matrices. The error pops when i=4792 so I am not far from reaching i=6000:

for i=2:size(PC,1)
    for j=2:size(PC,2)
RG(i,j)=((PC(i,j)-PC(i-1,j))+(Acr(i,j)-Acr(i-1,j)))./PC(i-1,j);
    end
end

Answer 1

[Fangjun Jiang]

Did you pre-allocate RG? The three matrices take about 2G bytes of memory. Do you need keep PC and Acr? If not, there might be a way to vectorize to get RG without for-loop.

>> 6000*14771*3*8

ans =

2.1270e+009

[joseph Frank]

pre-allocating RG solved the problem and the program finished very quickly. Thanks