MATLAB Answers

Matlab performance handling large arrays

2 views (last 30 days)
Daniel on 10 Aug 2012
I have a code which depending on how many iterations I choose, may end up with arrays in excess of 5,000,000 by 3. I soon started running into "out of memory" type problems because of the individual size of the large matrices.
I initialised my matrices beforehand, so all memory should have been allocated. Still sometimes I would get memory probs, but more interesting is that as the simulation progressed, it got gradually slower, eventually reaching 100% but at an exponentially slower pace it seemed.
I solved it by using smaller arrays, and after a set number of steps, assigning those matrices to other fixed matrices (which are not accessed in every loop), and then restarting the "looping array". So for e.g. say A is an array accessed in every loop. After the first 100 loops, i assign A to B (which is fixed and not accssed). I clean out A, then use it to fill in the next 101-200 steps, assign that portion to say array C, etc etc. So A is the only "dynamic" variable here.
So I fixed the issue it runs much better now, I am just curious to know why this would happen? Can anyone shed some light?

Answers (1)

Jan on 19 Aug 2012
A [5e6 x 3] double array needs 120MB RAM. This should not cause out-of-error messages. To understand the cause of your problems, we have to see the code.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!