[petsc-users] Floating point exception

[baikadi pranay]

Hello PETSc users,

I am currently trying to build a 1-D Schrodinger solver. I have built my
hamiltonian matrix (of size 121 x 121) and i'm trying to find the
eigenvalues. I have the following lines of code for the solver:

*call EPSCreate(PETSC_COMM_WORLD,eps,ierr)*

*call EPSSetOperators(eps,ham,S,ierr)call
EPSSetProblemType(eps,EPS_GHEP,ierr)*



*call EPSSetFromOptions(eps,ierr)call
EPSSetDimensions(eps,10,PETSC_DEFAULT_INTEGER,PETSC_DEFAULT_INTEGER,ierr)call
EPSSolve(eps,ierr)call EPSDestroy(eps,ierr)*

At the EPSSolve line, i get the following error:





*[0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------[0]PETSC
ERROR: Floating point exception[0]PETSC ERROR: Vec entry at local location
0 is not-a-number or infinite at end of function: Parameter number
3[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html
<http://www.mcs.anl.gov/petsc/documentation/faq.html> for trouble
shooting.[0]PETSC ERROR: Petsc Release Version 3.11.1, Apr, 12, 2019*

I am using the options *-st_pc_factor_shift_type NONZERO
-st_pc_factor_shift_amount 1*     ( else I end up getting the "zero pivot
in LU factorization" error ).

I outputted my matrix to matlab and confirmed that the null space is empty
and the matrix is not singular. I am not sure why I'm getting this error.
Could you provide me a hint as to how to solve this problem.

Sincerely,
Pranay.
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