MatDestroy(&B) should not be called, for the same reason as the PC - it is
owned by the PC object, it just gives you a pointer. This is stated in the
manpage of PCFactorGetMatrix:
Notes:
Does not increase the reference count for the matrix so DO NOT destroy it
As a general rule, objects returned by functions XXXGetYYY() should not be
destroyed, while objects returned by functions XXXCreateYYY() should.
Jose
> El 24 mar 2020, a las 18:26, Perceval Desforges
> <perceval.desfor...@polytechnique.edu> escribió:
>
> Thank you but I am still confused, I still get the same error message when
> calling KSPDestroy(). My code looks something like this:
>
>
>
> ierr = MatShift(M,-E);
> ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);
> ierr = KSPSetOperators(ksp,M,M);
> ierr = KSPSetType(ksp,KSPPREONLY);
> ierr = KSPGetPC(ksp,&pc);
> ierr = PCSetType(pc,PCCHOLESKY);
> ierr = KSPSetUp(ksp);
> ierr = PCFactorGetMatrix(pc,&B);
> ierr = MatGetInertia(B,&nneg,&nzero,&npos);
> ierr = PetscPrintf(PETSC_COMM_WORLD,"nneg: %D nzero: %D npos: %D
> \n",nneg,nzero,npos);
> ierr = MatDestroy(&B);
> ierr = MatDestroy(&M);
> ierr = KSPDestroy(&ksp);
>
> where I've defined the matrix M beforehand. What am I doing wrong?
>
> Thanks again,
>
> Best regards,
>
> Perceval,
>
>
>
>> If you obtained the PC object with KSPGetPC() then you do not have to
>> destroy it, only the KSP object. KSPGetPC() only gives a pointer to the
>> internal object, which is managed by the KSP.
>> Jose
>>
>>
>>> El 24 mar 2020, a las 17:18, Perceval Desforges
>>> <perceval.desfor...@polytechnique.edu> escribió:
>>>
>>> Thank you very much, this seems to work well.
>>>
>>> I have another question linked to this which is probably a bit basic so I
>>> apologize.
>>>
>>> At the end of my program, I want to destroy all the petsc objects. I start
>>> by destroying the matrixes, then the ksp and pc objects similarly to how
>>> it's done in the examples. However I get an error when attempting to
>>> destroy the KSP and PC objects :
>>>
>>> [0]PETSC ERROR: Invalid argument
>>>
>>> [0]PETSC ERROR: Wrong type of object: Parameter # 1
>>>
>>> I've tried switching the order around, but I still get the same errors.
>>>
>>> And if I don't destroy these objects I get a memory leak, which I'd like to
>>> avoid.
>>>
>>> My question is I don't really understand when and how I'm supposed to
>>> destroy the KSP and PC objects?
>>>
>>> Thanks again,
>>>
>>> Best regards,
>>>
>>> Perceval,
>>>
>>>
>>>
>>>
>>>
>>>> You can do this directly in PETSc. Create a KSP object with PREONLY and
>>>> PCCHOLESKY (or just a PC object). Then call KSPSetUp (or PCSetUp) and
>>>> extract the factored matrix with PCFactorGetMatrix(). Then call
>>>> MatGetInertia() on the factored matrix. Repeat this for each value of E.
>>>>
>>>> I guess it can be even shorter if you call MatCholeskyFactor() directly.
>>>>
>>>> Jose
>>>>
>>>>
>>>>> El 24 mar 2020, a las 11:07, Perceval Desforges
>>>>> <perceval.desfor...@polytechnique.edu> escribió:
>>>>>
>>>>> Dear petsc developers,
>>>>>
>>>>> I am interested in calculating the inertias of matrixes. Specifically,
>>>>> for a certain matrix A, and for different real numbers E, I want to
>>>>> calculate the inertias of (A - E * I), in order to get the number of
>>>>> eigenvalues less than E.
>>>>>
>>>>> In order to do this I have been setting up a slepc EPS object with
>>>>> spectrum slicing, and using EPSKrylovSchurGetInertias. I realize this is
>>>>> a bit convoluted, and was wondering if there is a better way to do this?
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Perceval,
>>>>>
>>>>> P.S. my last email seems to not have been sent (I couldn't find it in the
>>>>> archives) so I am trying again...
>>>>>
>>>
>>>
>
>
