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...
