Multiple communicators

[irfan.khan at gatech.edu]

I don't explicitly use the communicator PETSC_COMM_WORLD. Instead I used MPI_COMM_WORLD, which according to the manual should be the same. 

However, I create two new communicator from MPI_COMM_WORLD using MPI_Comm_split(). LBM_Comm and FEA_Comm. Only the ranks in FEA_Comm make use of KSP solver and PARMETIS. When creating objects for mesh partitioning (MatPartitioningCreate()) and solver (KSPCreate()), I use the new communicator FEA_Comm. Would this have any effect on the command line options? 

Regards 
Irfan 


I am not sure what you are doing, but something is wrong in this code. Using different communicators does not 
have much to do with options. Any object (like a KSP) can be created using a subcomm of WORLD. Are you 
setting PETSC_COMM_WORLD to something different? That is not necessary here. 

Matt 






Thank you 
Irfan 

----- Original Message ----- 
From: "Matthew Knepley" < knepley at gmail.com > 
To: "PETSc users list" < petsc-users at mcs.anl.gov > 
Sent: Tuesday, November 24, 2009 8:03:00 PM GMT -05:00 US/Canada Eastern 
Subject: Re: Multiple communicators 

On Tue, Nov 24, 2009 at 6:59 PM, < irfan.khan at gatech.edu > wrote: 





Hello 

Does the procedure for providing command line options and to obtain profiling data through -log_summary change if there are multiple MPI communicators in a petsc code? 


There is always WORLD, so it should be fine unless I misunderstand your question. 

Matt 




If so, can somebody point me to information, references on how to provide command line options if there are multiple communicators? 

Thank you 
Irfan 

-- 
PhD Candidate 
G.W. Woodruff School of Mechanical Engineering 
Georgia Institute of Technology 
Atlanta, GA (30332) 



-- 
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. 
-- Norbert Wiener 


-- 
PhD Candidate 
G.W. Woodruff School of Mechanical Engineering 
Georgia Institute of Technology 
Atlanta, GA (30332) 



-- 
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. 
-- Norbert Wiener 


-- 
PhD Candidate 
G.W. Woodruff School of Mechanical Engineering 
Georgia Institute of Technology 
Atlanta, GA (30332) 
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