[petsc-users] Problem With MatRestoreRow

[ked1 at rice.edu]

I am attempting to build a matrix and then get a row (or the number of  
nonzeros in the row) in Fortran 90. I can build the matrix and use it  
for calculations such as matrix multiplication, but if I call  
MatGetRow and then MatRestoreRow, I get an error about object type.

However, if I reduce the size of the arrays I'm using in the  
MatSetValues command, everything works (except that I'm not building  
what I want).


The section of my code giving trouble is below.

---------------------- CODE  BEGINS ----------------------------
Mat  M
PetscInt  dnnz(locneq), onnz(locneq), rows(64)
PetscScalar Me(64*64)

...

dnnz = 64
onnz = 0
call  
MatCreateMPIAIJ(petsc_comm_world,locneq,locneq,gnngu,gnngu,petsc_null,dnnz,petsc_null,onnz,M,ierr)

Me = 1.0D0
if (procid==0) then
   do ii=1,ne        ! for all elements
     do jj=1,64      ! for number of rows
       kk = uconn(ii,jj)  ! get local node number
       rows(jj) = gnoden(kk)-1  ! get global node number
     end do
     call MatSetValues(M,64,rows,64,rows,Me,add_values,ierr)
   end do
end if

! Assemble
call MatAssemblyBegin(M,mat_final_assembly,ierr)
call MatAssemblyEnd(M,mat_final_assembly,ierr)

! Get number of nonzero columns
if (procid==0) then
   call MatGetRow(M,0,ii,petsc_null,petsc_null,ierr)
   print *, ii
   call MatRestoreRow(M,0,ii,petsc_null,petsc_null,ierr)
end if
---------------------- CODE  ENDS ----------------------------

The error I get is

[0]PETSC ERROR: --------------------- Error Message  
------------------------------------
[0]PETSC ERROR: Invalid argument!
[0]PETSC ERROR: Wrong type of object: Parameter # 1!
[0]PETSC ERROR:  
------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Release Version 3.1.0, Patch 8, Thu Mar 17  
13:37:48 CDT 2011
[0]PETSC ERROR: See docs/changes/index.html for recent updates.
[0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[0]PETSC ERROR: See docs/index.html for manual pages.
[0]PETSC ERROR:  
------------------------------------------------------------------------
[0]PETSC ERROR: ./semg3par on a linux-gnu named login1.sugar.rice.edu  
by ked1 Thu Aug 11 10:52:46 2011
[0]PETSC ERROR: Libraries linked from  
/projects/bch3862/petsc/linux-gnu-c-debug/lib
[0]PETSC ERROR: Configure run at Sun Jul 17 15:34:01 2011
[0]PETSC ERROR: Configure options --with-cc=icc --with-fc=ifort  
--download-f-blas-lapack=1 --download-mpich=1
[0]PETSC ERROR:  
------------------------------------------------------------------------
[0]PETSC ERROR: MatRestoreRow() line 388 in src/mat/interface/matrix.c

Line 388 in matrix.c is

PetscValidHeaderSpecific(mat,MAT_COOKIE,1);

Again, if I lower the number of rows, it will not give an error. In  
this case, replacing all instances of 64 with 46 will give no error.  
Going to 47 gives a error.

Thanks for any help.

Kenny