[petsc-users] Problem in MatSetValues

[Eda Oktay]

Dear Matt,

I understood that you are right. I changed sizeof(values) with ncols, it
gives matrix correctly.

However, now I get an error in EPSGetEigenpair:

0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[0]PETSC ERROR: Argument out of range
[0]PETSC ERROR: Argument 2 out of range
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.10.3, Dec, 18, 2018
[0]PETSC ERROR: ./ENYENI_FINAL on a arch-linux2-c-debug named
70a.wls.metu.edu.tr by edaoktay Mon Mar 11 16:17:25 2019
[0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++
--with-fc=gfortran --with-cxx-dialect=C++11 --download-openblas
--download-metis --download-parmetis --download-superlu_dist
--download-slepc --download-mpich
[0]PETSC ERROR: #1 EPSGetEigenpair() line 398 in
/home/edaoktay/petsc-3.10.3/arch-linux2-c-debug/externalpackages/git.slepc/src/eps/interface/epssolve.c

I understood from this error that the matrix does not converge. However, I
tested in MATLAB and it converges. The matrix is true now, so this cannot
be from the matrix.

Thanks,

Eda

Eda Oktay <eda.oktay at metu.edu.tr>, 11 Mar 2019 Pzt, 16:07 tarihinde şunu
yazdı:

> Dear Matt,
>
> I printed in wrong state, ncols gives right solution.
>
> But I still can't understand the first problem.
>
> Eda
>
> Eda Oktay <eda.oktay at metu.edu.tr>, 11 Mar 2019 Pzt, 16:05 tarihinde şunu
> yazdı:
>
>> Dear Matt,
>>
>> Thank you for answering. First of all, sizeof(vals) returns to number of
>> entries, I checked. Secondly, I found a problem:
>>
>> ncols gives me 6.95328e-310. However, I checked the matrix L, it was
>> computed properly.
>>
>> Why can ncols give such a value?
>>
>> Thanks,
>>
>> Eda
>>
>> Matthew Knepley <knepley at gmail.com>, 11 Mar 2019 Pzt, 15:56 tarihinde
>> şunu yazdı:
>>
>>> On Mon, Mar 11, 2019 at 8:27 AM Eda Oktay via petsc-users <
>>> petsc-users at mcs.anl.gov> wrote:
>>>
>>>> Hello,
>>>>
>>>> I have a following part of a code which tries to change the nonzero
>>>> values of matrix L with -1. However in MatSetValues line, something happens
>>>> and some of the values in matrix turns into 1.99665e-314 instead of -1.
>>>> Type of arr is defined as PetscScalar and arr is produced correctly. What
>>>> can be the problem, is there a mistake about types?
>>>>
>>>> Thanks,
>>>>
>>>> Eda
>>>>
>>>>
>>>> for(rw = mm; rw<nn; ++rw){
>>>>
>>>>             ierr = MatGetRow(L,rw,&ncols,&cols,&vals);CHKERRQ(ierr);
>>>>
>>>>             s = sizeof(vals);
>>>>
>>>
>>> This is wrong. sizeof(vals) gives bytes, not entries. Why don't you just
>>> use ncols here?
>>>
>>>   Matt
>>>
>>>
>>>>             ierr = PetscMalloc1(s,&arr);CHKERRQ(ierr);
>>>>
>>>>             for(j=0;j<s;++j){
>>>>
>>>>                 arr[j]=-1.0;
>>>>             }
>>>>             ierr =
>>>> MatSetValues(NSymmA,1,&rw,ncols,cols,arr,INSERT_VALUES);CHKERRQ(ierr);
>>>>             ierr = MatRestoreRow(L,rw,&ncols,&cols,&vals);CHKERRQ(ierr);
>>>>         }
>>>>
>>>
>>>
>>> --
>>> 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
>>>
>>> https://www.cse.buffalo.edu/~knepley/
>>> <http://www.cse.buffalo.edu/~knepley/>
>>>
>>
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