solve_GEP_shiftinvert

module opensg.utils.solid

opensg.utils.solid.solve_GEP_shiftinvert(A: petsc4py.PETSc.Mat, B: petsc4py.PETSc.Mat, problem_type: slepc4py.SLEPc.EPS.ProblemType = slepc4py.SLEPc.EPS.ProblemType.GHEP, solver: slepc4py.SLEPc.EPS.Type = slepc4py.SLEPc.EPS.Type.KRYLOVSCHUR, nev: int = 2, tol: float = 1e-06, max_it: int = 1000, target: float = 5, shift: float = 1) → slepc4py.SLEPc.EPS

Solve generalized eigenvalue problem A*x=lambda*B*x using shift-and-invert as spectral transform method. Parameters ———- A

The matrix A

B

The matrix B

problem_type

The problem type, for options see: https://bit.ly/3gM5pth

solver:

Solver type, for options see: https://bit.ly/35LDcMG

nev

Number of requested eigenvalues.

tol

Tolerance for slepc solver

max_it

Maximum number of iterations.

target

Target eigenvalue. Also used for sorting.

shift

Shift ‘sigma’ used in shift-and-invert.

interval

A tuple (min_val, max_val) to restrict the search to a specific interval on the real axis. To search for only positive eigenvalues, you could use interval=(1e-9, PETSc.DECIMAL_MAX). This feature is supported by solvers like KRYLOVSCHUR.

Returns:

• EPS

• The SLEPc solver