Hello, I was able to fix the problem. You are correct that the matrix B is singular although that was not the intention. I am using fortran and although i knew that PETSc uses 0-based indexing for fortran, I forgot to take this into account while filling out the B matrix. This resulted in the program accessing matrix elements which are essentially zero.
Also I am not using the *-st_pc_factor_shift_amount* option or the *-st_pc_factor_shift_type *and it works fine. Thank you for your time. Best wishes, Pranay. On Sun, Dec 1, 2019 at 9:33 AM Matthew Knepley <[email protected]> wrote: > On Sat, Nov 30, 2019 at 3:56 PM baikadi pranay <[email protected]> > wrote: > >> Hello, >> >> The entire output is the following: >> > > Okay, you are definitely getting an infinity in the output vector from the > LU solve, so you are giving it a singular matrix. > I am guessing this is B? How can you justify using a singular B? > Also, -st_pc_factor_shift_amount 1 is strange. You > would normally use a very small offset like 1.0e-10 or something. > > Thanks, > > Matt > > >> [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 >> for trouble shooting. >> [0]PETSC ERROR: Petsc Release Version 3.11.1, Apr, 12, 2019 >> [0]PETSC ERROR: ./a.out on a linux-gnu-c-debug named >> agave1.agave.rc.asu.edu by pbaikadi Sat Nov 30 14:54:31 2019 >> [0]PETSC ERROR: Configure options >> [0]PETSC ERROR: #1 VecValidValues() line 28 in >> /packages/7x/petsc/3.11.1/petsc-3.11.1/src/vec/vec/interface/rvector.c >> [0]PETSC ERROR: #2 PCApply() line 464 in >> /packages/7x/petsc/3.11.1/petsc-3.11.1/src/ksp/pc/interface/precon.c >> [0]PETSC ERROR: #3 KSP_PCApply() line 281 in >> /packages/7x/petsc/3.11.1/petsc-3.11.1/include/petsc/private/kspimpl.h >> [0]PETSC ERROR: #4 KSPSolve_PREONLY() line 22 in >> /packages/7x/petsc/3.11.1/petsc-3.11.1/src/ksp/ksp/impls/preonly/preonly.c >> [0]PETSC ERROR: #5 KSPSolve() line 782 in >> /packages/7x/petsc/3.11.1/petsc-3.11.1/src/ksp/ksp/interface/itfunc.c >> [0]PETSC ERROR: #6 STMatSolve() line 193 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/sys/classes/st/interface/stsles.c >> [0]PETSC ERROR: #7 STApply_Shift() line 25 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/sys/classes/st/impls/shift/shift.c >> [0]PETSC ERROR: #8 STApply() line 57 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/sys/classes/st/interface/stsolve.c >> [0]PETSC ERROR: #9 EPSGetStartVector() line 797 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/eps/interface/epssolve.c >> [0]PETSC ERROR: #10 EPSSolve_KrylovSchur_Symm() line 32 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/eps/impls/krylov/krylovschur/ks-symm.c >> [0]PETSC ERROR: #11 EPSSolve() line 149 in >> /packages/7x/slepc/3.11.1/slepc-3.11.1/src/eps/interface/epssolve.c >> >> Regards, >> Pranay. >> >> On Sat, Nov 30, 2019 at 2:46 PM Matthew Knepley <[email protected]> >> wrote: >> >>> On Sat, Nov 30, 2019 at 3:19 PM baikadi pranay <[email protected]> >>> wrote: >>> >>>> 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* >>>> >>> >>> You need to show the entire stack trace that is output here. >>> >>> Thanks, >>> >>> Matt >>> >>> >>>> 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. >>>> >>> >>> >>> -- >>> What most experimenters take for granted before they begin their >>> experiments is infinitely more interesting than any results to which their >>> experiments lead. >>> -- Norbert Wiener >>> >>> https://www.cse.buffalo.edu/~knepley/ >>> <http://www.cse.buffalo.edu/~knepley/> >>> >> > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> >
