RE: How to know number of processors and size of RAM that should be used.

From: yueh wang <cw5b_at_msn.com>
Date: Sat, 12 Mar 2011 01:16:21 -0800

After you compiled the code, you can Unix command 'size' to know the size of your executable file.
The execuable size increases with the resolution (and may depend on the machine and compilers).
For a single node computing, if the size of your executable exceeds the RAM of your computer,
then your code cannot be executed on that machine (node).

Similarly, for parallel computings with domain decomposition, the executable size on each node must not exceed the RAM of a single node.


From: honeysh24_at_gmail.com
Date: Thu, 10 Mar 2011 17:47:05 +0530
To: gadget-list_at_MPA-Garching.MPG.DE
Subject: [gadget-list] How to know number of processors and size of RAM that should be used.

Hello all,
I am new to gadget2.
I want to know that how many processors should I use?
Followings are details:
Number of particles= 1500^3 = 3,375,000,000
PMGRID=1500
RAM per processor = 4GB
 ParallelFactor=1.5
TreeFactor=0.75

The formula
M1=ParallelFactor* (Ntot/Np) * (68 + TreeFactor*64)

I do not know the use of Np(number of processor).
How to use this formula. What is M1. Please tell in detail.
Please also tell me how to calculate total RAM required to run this simulation.
Thanks in advance.
                                               
Received on 2011-03-12 10:16:24