[petsc-users] Getting Eigenvectors from a SLEPc run (in python)

[Jose E. Roman]

El 09/06/2014, a las 20:45, Alex Eftimiades escribió:

> Hi
> 
> I am trying solve a sparse generalized Hermitian matrix eigenvalue problem. I am trying to use slepc4py to get both the eigenvalues and eigenvectors, but I am unable to get the eigenvectors. Instead, I keep getting None. Do you have any example code that can do this? I copied the code I have tried below.
> 
> Thanks,
> Alex Eftimiades
> 
>    xr, tmp = A.getVecs()
>    xi, tmp = A.getVecs()
> 
>    # Setup the eigensolver
>    E = SLEPc.EPS().create()
>    E.setOperators(A,M)
>    E.setDimensions(50, PETSc.DECIDE)
> 
>    E.setWhichEigenpairs("SM")
> 
>    E.solve()
> 
>    vals = []
>    vecs = []
>    for i in range(E.getConverged()):
>        val = E.getEigenpair(i, xr, xi)
>        vecr, veci = E.getEigenvector(i, xr, xi)
>        vals.append(val)
>        vecs.append(complex(vecr, veci))
> 
>    vals = asarray(vals)
>    vecs = asarray(vecs).T

Eigenvectors are not obtained as return values. Instead, the arguments of getEigenvector() are mutable, so after the call they contain the eigenvector.

Jose