[petsc-users] Preallocation of sequential matrix

[Maahi Talukder]

Thank you all. I will look into that.

Maahi

On Tue, Apr 23, 2019, 11:40 PM Zhang, Junchao <jczhang at mcs.anl.gov> wrote:

> The error message has
>
> [0]PETSC ERROR: New nonzero at (61,124) caused a malloc
> [0]PETSC ERROR: New nonzero at (124,186) caused a malloc
>
> You can check your code to see if you allocated spots for these nonzeros.
>
> --Junchao Zhang
>
>
> On Tue, Apr 23, 2019 at 8:57 PM Maahi Talukder via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
>> Dear All,
>>
>>
>> I am trying to preallocate the no of nonzeros in my matrix using the
>> parameter 'nnz'. Here 'row' is the parameter 'nnz'. The part of the code
>> that does that is the following-
>>
>>
>> ..........................................................................................................................................................................................
>> *Do j = 2,xmax-1*
>>
>> *Do i = 2,ymax-1*
>>
>> *a = (ymax-2)*(j-2)+i-1-1*
>>
>> *If(j.eq.2 .and. i .ge. 3 .and. i .le. (ymax-2))then*
>> *row(a) = 6*
>>
>> *else if (j.eq.(xmax-1) .and. i.ge.3 .and. i .le. (ymax-2)) then*
>> *row(a) = 6*
>>
>> *else if(i.eq.2 .and. j.ge.3 .and. j.le.(xmax-2))then*
>> *row(a) = 6*
>>
>> *else if(i.eq.(ymax-1) .and. j.ge.3 .and. j.le.(xmax-2)) then*
>> *row(a) = 6*
>>
>> *else if(i.eq.2 .and. j.eq.2) then*
>> *row(a) = 4*
>>
>> *else if (i.eq.2 .and. j .eq. (xmax-1)) then*
>> *row(a)= 4*
>>
>> *else if (i.eq.(ymax-1) .and. j .eq. 2) then*
>> *row(a) = 4*
>>
>> *else if (i .eq. (ymax-1) .and. j .eq. (xmax-1)) then*
>> *row(a) = 4*
>>
>> *else*
>> *row(a) = 9*
>>
>> *end if*
>>
>>
>> *end do *
>>
>> *end do *
>>
>>
>> *call MatCreateSeqAIJ(PETSC_COMM_SELF,N,N,ze,row,Mp,ierr)*
>>
>>
>> .................................................................................................................................................................................................
>>
>> But I get the following error message :
>>
>> [0]PETSC ERROR: --------------------- Error Message
>> --------------------------------------------------------------
>> [0]PETSC ERROR: Argument out of range
>> [0]PETSC ERROR: New nonzero at (61,124) caused a malloc
>> Use MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE) to turn
>> off this check
>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html
>> for trouble shooting.
>> [0]PETSC ERROR: Petsc Release Version 3.10.2, unknown
>> [0]PETSC ERROR: ./Test5 on a arch-opt named CB272PP-THINK1 by maahi Tue
>> Apr 23 21:39:26 2019
>> [0]PETSC ERROR: Configure options --with-debugging=0
>> --download-fblaslapack=1 PETSC_ARCH=arch-opt
>> [0]PETSC ERROR: #1 MatSetValues_SeqAIJ() line 481 in
>> /home/maahi/petsc/src/mat/impls/aij/seq/aij.c
>> [0]PETSC ERROR: #2 MatSetValues() line 1349 in
>> /home/maahi/petsc/src/mat/interface/matrix.c
>> [0]PETSC ERROR: --------------------- Error Message
>> --------------------------------------------------------------
>> [0]PETSC ERROR: Argument out of range
>> [0]PETSC ERROR: New nonzero at (124,186) caused a malloc
>> Use MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE) to turn
>> off this check
>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html
>> for trouble shooting.
>> [0]PETSC ERROR: Petsc Release Version 3.10.2, unknown
>> [0]PETSC ERROR: ./Test5 on a arch-opt named CB272PP-THINK1 by maahi Tue
>> Apr 23 21:39:26 2019
>> [0]PETSC ERROR: Configure options --with-debugging=0
>> --download-fblaslapack=1 PETSC_ARCH=arch-opt
>> [0]PETSC ERROR: #3 MatSetValues_SeqAIJ() line 481 in
>> /home/maahi/petsc/src/mat/impls/aij/seq/aij.c
>> [0]PETSC ERROR: #4 MatSetValues() line 1349 in
>> /home/maahi/petsc/src/mat/interface/matrix.c
>> [0]PETSC ERROR: --------------------- Error Message
>> --------------------------------------------------------------
>>
>> .................................................................................................................................................................................
>>
>> But instead of using 'nnz', if I put a upper bound for 'nz',  the code
>> works fine.
>>
>> Any idea what went wrong?
>>
>> Thanks,
>> Maahi Talukder
>>
>>
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