<div dir="ltr">Hi Barry<div><br></div><div>Thanks for pointing out the error. I think the problem coming from the zero fieldsplit in proc 0. In this modified example, I parameterized the matrix size and block size, so when you're executing</div><div><br></div><div>mpirun -np 2 ./ex -mat_size 40 -block_size 2 -method 1<br></div><div class="gmail_extra"><br></div><div class="gmail_extra">everything was fine. With method = 1, fieldsplit size of B is nonzero and is divided by the block size.</div><div class="gmail_extra"><br></div><div class="gmail_extra">With method=2, i.e mpirun -np 2 ./ex -mat_size 40 -block_size 2 -method 2, the fieldsplit B is zero on proc 0, and the error is thrown</div><div class="gmail_extra"><br></div><div class="gmail_extra"><div class="gmail_extra"><div class="gmail_extra">[1]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------</div><div class="gmail_extra">[1]PETSC ERROR: Arguments are incompatible</div><div class="gmail_extra">[1]PETSC ERROR: Local size 11 not compatible with block size 2</div><div><br></div><div>This is somehow not logical, because 0 is divided by block_size.</div><div><br></div><div>Furthermore, if you execute "mpirun -np 2 ./ex -mat_size 20 -block_size 2 -method 2", the code hangs at ISSetBlockSize, which is pretty similar to my original problem. Probably the original one also hangs at ISSetBlockSize, which I may not realize at that time.</div><div><br></div></div></div><div class="gmail_extra"><div><div class="gmail-m_-1790415243529344442gmail_signature"><div dir="ltr">Giang</div></div></div>
<br><div class="gmail_quote">On Wed, Jun 14, 2017 at 5:29 PM, Barry Smith <span dir="ltr"><<a href="mailto:bsmith@mcs.anl.gov" target="_blank">bsmith@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
You can't do this<br>
<br>
ierr = MatSetSizes(A,PETSC_DECIDE,N,N<wbr>,N);CHKERRQ(ierr);<br>
<br>
use PETSC_DECIDE for the third argument<br>
<br>
Also this is wrong<br>
<br>
for (i = Istart; i < Iend; ++i)<br>
{<br>
ierr = MatSetValue(A,i,i,2,INSERT_VAL<wbr>UES);CHKERRQ(ierr);<br>
ierr = MatSetValue(A,i+1,i,-1,INSERT_<wbr>VALUES);CHKERRQ(ierr);<br>
ierr = MatSetValue(A,i,i+1,-1,INSERT_<wbr>VALUES);CHKERRQ(ierr);<br>
}<br>
<br>
you will get<br>
<br>
$ petscmpiexec -n 2 ./ex1<br>
0: Istart = 0, Iend = 60<br>
1: Istart = 60, Iend = 120<br>
<span class="gmail-m_-1790415243529344442gmail-">[1]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--<br>
</span>[1]PETSC ERROR: Argument out of range<br>
[1]PETSC ERROR: Row too large: row 120 max 119<br>
[1]PETSC ERROR: See <a href="http://www.mcs.anl.gov/petsc/documentation/faq.html" rel="noreferrer" target="_blank">http://www.mcs.anl.gov/petsc/d<wbr>ocumentation/faq.html</a> for trouble shooting.<br>
[1]PETSC ERROR: Petsc Development GIT revision: v3.7.6-4103-g93161b8192 GIT Date: 2017-06-11 14:49:39 -0500<br>
[1]PETSC ERROR: ./ex1 on a arch-basic named Barrys-MacBook-Pro.local by barrysmith Wed Jun 14 18:26:52 2017<br>
[1]PETSC ERROR: Configure options PETSC_ARCH=arch-basic<br>
[1]PETSC ERROR: #1 MatSetValues_MPIAIJ() line 550 in /Users/barrysmith/Src/petsc/sr<wbr>c/mat/impls/aij/mpi/mpiaij.c<br>
[1]PETSC ERROR: #2 MatSetValues() line 1270 in /Users/barrysmith/Src/petsc/sr<wbr>c/mat/interface/matrix.c<br>
[1]PETSC ERROR: #3 main() line 30 in /Users/barrysmith/Src/petsc/te<wbr>st-dir/ex1.c<br>
[1]PETSC ERROR: PETSc Option Table entries:<br>
[1]PETSC ERROR: -malloc_test<br>
<br>
You need to get the example working so it ends with the error you reported previously not these other bugs.<br>
<div><div class="gmail-m_-1790415243529344442gmail-h5"><br>
<br>
> On Jun 12, 2017, at 10:19 AM, Hoang Giang Bui <<a href="mailto:hgbk2008@gmail.com" target="_blank">hgbk2008@gmail.com</a>> wrote:<br>
><br>
> Dear Barry<br>
><br>
> I made a small example with 2 process with one empty split in proc 0. But it gives another strange error<br>
><br>
> [1]PETSC ERROR: --------------------- Error Message ------------------------------<wbr>------------------------------<wbr>--<br>
> [1]PETSC ERROR: Arguments are incompatible<br>
> [1]PETSC ERROR: Local size 31 not compatible with block size 2<br>
><br>
> The local size is always 60, so this is confusing.<br>
><br>
> Giang<br>
><br>
> On Sun, Jun 11, 2017 at 8:11 PM, Barry Smith <<a href="mailto:bsmith@mcs.anl.gov" target="_blank">bsmith@mcs.anl.gov</a>> wrote:<br>
> Could be, send us a simple example that demonstrates the problem and we'll track it down.<br>
><br>
><br>
> > On Jun 11, 2017, at 12:34 PM, Hoang Giang Bui <<a href="mailto:hgbk2008@gmail.com" target="_blank">hgbk2008@gmail.com</a>> wrote:<br>
> ><br>
> > Hello<br>
> ><br>
> > I noticed that my code stopped very long, possibly hang, at PCFieldSplitSetIS. There are two splits and one split is empty in one process. May that be the possible reason that PCFieldSplitSetIS hang ?<br>
> ><br>
> > Giang<br>
><br>
><br>
</div></div>> <ex.c><br>
<br>
</blockquote></div><br></div></div>