What is the equivalent of --map-by-node

[AThar2]

To briefly explain what I want to achieve: 

I am running two codes coupled with mpi like the following:

   mpirun -np X ./exe1 : -np Y ./exe2

However, I have to control  how this is distributed across each nodes - so say we got three nodes I would create such hostfile

comp00
comp00
comp01
comp01
comp02
comp02
comp00
comp00
comp01
comp01
comp02
comp02

I would then run the following:

mpirun --hostfile myhost -np 6 ./exe1  : -np 6 ./exe2

So basically the first 6 instances in the "myhost" will be reserved for exe1 and the last 6 for exe2. 

This works all fine.
However, the rank numbering is not what I want. With Intel MPI I get the following for say the first 6 ranks on exe1 

0 rank: comp00 
1 rank:comp01

2 rank: comp02

3 rank:comp00

4 rank: comp01

5 rank: comp02

I want to make sure that rank 0 and 1 belong to comp00 and 2-3 to comp01 etc etc 

With OpenMPI I achieve this by doing the following

mpirun --hostfile myhost -np 6 ./exe1  : --map-by node -np 6 ./exe2

Notice the map-by node has to be on the second code 'exe2' - but this ensures that both exe1 and exe2 have their associated ranks clustered to the same node. 

How can I do the same with intelMPI -

[GouthamK_Intel · Accepted solution]

Hi Ali Thari,

Thanks for briefly explaining the issue which you are facing, from the explanation provided by you I assume that you wanted to run the consecutive ranks on a single node in a round-robin fashion instead of the default one which assigns a single rank on a single node and then assigns other ranks on round-robin manner.

If this is the information you wanted to seek, then please use -ppn (# of processes per node) option to set the number of processes to launch on each node.

Example:

for more details of ppn please refer to the below link:

https://software.intel.com/content/www/us/en/develop/documentation/mpi-developer-guide-linux/top/running-applications/running-an-mpi-program.html

If your issue still persists/if your issue is something else, please let us know.

Have a Good day!

Thanks & Regards

Goutham

[GouthamK_Intel]

Hi, 

Thanks for the confirmation!

As this issue has been resolved, we will no longer respond to this thread. 

If you require any additional assistance from Intel, please start a new thread. 

Any further interaction in this thread will be considered community only. 

Have a Good day.

Thanks & Regards

Goutham