<html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>Actually I am using fortran. But I also tried with C and yes I am casting A to PetscObject.</div>
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<div>To confirm, are you casting A to PetscObject? e.g.
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<div> MPI_Comm comm;</div>
<div> /* ... */</div>
PetscObjectGetComm((PetscObject)A,&comm);
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<div class="gmail_attr">Am Mi., 22. Apr. 2020 um 07:11 Uhr schrieb Marius Buerkle <<a href="mailto:mbuerkle@web.de" onclick="parent.window.location.href='mailto:mbuerkle@web.de'; return false;" target="_blank">mbuerkle@web.de</a>>:</div>
<blockquote class="gmail_quote" style="margin: 0.0px 0.0px 0.0px 0.8ex;border-left: 1.0px solid rgb(204,204,204);padding-left: 1.0ex;">Hi,<br/>
<br/>
What is PetscObjectGetComm expected to return? I thought it would give the MPI communicator the object lives on. So if I create A matrix on PETSC_COMM_WORLD a call of PetscObjectGetComm for A it would return PETSC_COMM_WORLD? But it seems to return something else, and while most of the nodes return a similar communicator some are giving a different one. That said, is there a way to get the MPI communicator a matrix lives on?<br/>
<br/>
Best,<br/>
Marius</blockquote>
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