Memory Allocation Error

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Esperanza
Posts: 4
Joined: 02 Jun 2011, 17:51

Memory Allocation Error

Post by Esperanza » 06 Jun 2011, 13:38

Hello,
I am running a bunched_beam with 1e8 particles. Code runs fine with 1e7 or less particles, but I get the following error when I try larger numbers:
PS_MemAllocError.jpg
The available memory is:
PS_Memory.jpg
So I don't understand this error.
Any Help?
Thanks, Esperanza Arab

ywang25
Posts: 52
Joined: 10 Jun 2008, 19:48

Re: Memory Allocation Error

Post by ywang25 » 06 Jun 2011, 14:12

The minimum theoretical memory requirement for this simulation is
8(double) x 7(6-dimensions+1ID) x 1e8=5.6GB, while it requires much more in practice. So a 32-bit system with memory limit of 4GB will not meet the memory requirement. The program tries to allocate in a contiguous space. It could fail to find a big trunk even you have swap space available. It will be extremely slow because of the limited memory, even if the computer is able to find enough space to hold the data out of the memory.

There are two possible solutions:
1) Use Pelegant on a distributed memory system. You can expect the simulation time to be reduced significantly as well;
2) Run the simulation on a 64-bit system with at least 16GB memory -- not recommended;

Yusong
Last edited by ywang25 on 06 Jun 2011, 14:27, edited 2 times in total.

Esperanza
Posts: 4
Joined: 02 Jun 2011, 17:51

Re: Memory Allocation Error

Post by Esperanza » 06 Jun 2011, 14:15

Thank you for your help.
-Esperanza

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