Re: Varying the Execution time (problem size)

From: Sanjay H A <>
Date: Wed, 05 Mar 2008 23:34:40 -0500 (EST)
Hi Yves

---------[ Received Mail Content ]----------

Subject : Re: [gadget-list] Varying the Execution time (problem size)

Date : Wed, 05 Mar 2008 14:58:24 +0100

From : Revaz Yves <>

To : Gadget General Discussion <gadget-list_at_MPA-Garching.MPG.DE>


Well, I'm not sure to understand clearly what you want to do.

Yes I want increase the cpu time needed to run ( i.e to vary the Execution time of an application).

If you want to increase the CPU time needed to run the example


you can of course increase the number of particles, i.e, creating a new


How to create a new gassphere_littleendian.dat?

file, which is not so easy at the beginning.

Easier to do is to vary the accuracy of time integration (see section

Accuracy of time integration

in gassphere.param). For example, decreasing ErrTolIntAccuracy will

increase the CPU time.

Or decreasing ErrTolTheta will also strongly increase the CPU time.

I want vary any one importatant parameter ( either number of particals, accuracy of time integration, etc...)
Just I want to know which is the important parameter which affects the execution time(CPU time), for each parameter file. ( Also guide me how to change those parameters)




Sanjay H A wrote:

> Hi All

> I am new to Gadget2.

> I am able to install Gadget2 and able to run one of the example

> program (lcdm_gas.param) using


> /usr/local/mpich-1.2.6/ch_p4/bin/mpirun -np 4 -machinefile hosts

> Gadget2 lcdm_gas.param


> Now I want to know, how to vary the execution time of the same example

> (on same number of processor) by varying any one of the parameter (

> which affects more on execution time, like in Molecular Dynamics

> Simulation, we can observe variation in Execution time by changing the

> number of particals).


> Can I know the parameter name for each example and also procedure to

> vary that parameter.


> Thanx in Advance

> Regards

> Sanjay







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Received on 2008-03-06 05:34:45

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