Petsc parallel vectors with two communicators

[Khan, Irfan]

Thanks Matt. That helped a lot. Things seem to be working now. 

Regards 
Irfan 

----- Original Message ----- 
From: "Matthew Knepley" <knepley at gmail.com> 
To: "PETSc users list" <petsc-users at mcs.anl.gov> 
Sent: Wednesday, March 25, 2009 9:08:24 AM GMT -05:00 US/Canada Eastern 
Subject: Re: Petsc parallel vectors with two communicators 

On Wed, Mar 25, 2009 at 1:05 AM, Khan, Irfan < irfan.khan at gatech.edu > wrote: 



Hi 
Can the petsc parallel vectors be used with two different communicators? For instance, I have created two different communicators called FEA_Comm and FSI_Comm. The total number of processes are x+y. FSI_Comm works on x+y but FEA_Comm works only on x. 

Now I am trying to create parallel vectors a1 and a2 such that a1 has entries from x+y processes but a2 has entries from only y processes. 

After splitting the communicators I assign PETSC_COMM_WORLD to FEA_Comm which works on only x processes. Subsequently petsc is initialized (PetscInitialize()). But when the parallel vectors are created, the processes hang. 

PETSC_COMM_WORLD should encompass all processes you wish to use in PETSc, so that means x+y. You can create Vec 
objects on subcommunicators, like x. 

Matt 



Any suggestions will be helpful 

Thankyou 
Irfan 
Graduate Research Assistant 
Woodruff school of Mechanical Engineering 
Atlanta, GA (30307) 
-- 
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 
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