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Re: Basic question about MPI

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In article <31beb7a0-0dd0-4647-8c63-12a67b9c0f6a@googlegroups.com>,
 <pradeep.kumar.jha@gmail.com> wrote:
> 
> Hello,
> 
> I have a very basic question about MPI.
> 
> I have a computer with 8 processors (each with 8 cores).  What is the difference between if I run a program simply by "./program" and "mpirun -np 6 /path/to/program" ? In the first case does the program just use one processor of the 8? If I want the program to use all the 8 processors at the same time, then I have to do with mpirun?

"./program" just runs the program (i.e., creates one process).  

"mpirun -np 6 ...." starts six copies of the program (i.e., creates six
processes).  As best I know this is the normal way of starting an MPI
program meant to run on multiple processors.

> 
> Something fundamental is buggin me. Any explanations will be highly appreciated.
> 

So I hope you're still checking the group ....


> Thank you,
> Pradeep
> 

-- 
B. L. Massingill
ObDisclaimer:  I don't speak for my employers; they return the favor.

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Basic question about MPI pradeep.kumar.jha@gmail.com - 2013-01-28 20:38 -0800
  Re: Basic question about MPI blmblm@myrealbox.com <blmblm.myrealbox@gmail.com> - 2013-02-02 19:13 +0000

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