tutorial step-36 failed with PETSc error number 76 while calling a SLEPc function

[Pragalv Karki]

Dear deal.II community,

                   I am new to deal.II and I had posted a question about this same issue yesterday. Perhaps I did not ask it correctly. I have been trying to simulate the wave equation on a particular kind of surface (I have attached a picture of that surface and the mesh). I created the mesh for that surface using gmsh. I was able to simulate the wave equation from step-23 on that surface and I am currently working to change the initial excitation, density, and tension. I also want to get the eigenfrequencies for this surface and as a start, I just wanted to learn how deal.II solves eigenspectrum using PETSc and SlEPc from step-36. But, when I try to run that tutorial as is it shows the error I have posted below. I thought the problem was not having the PETSc and SlEPc libraries so I went ahead and installed them but that still does not resolve the issue. Please let me know if you have run into this issue before and what you did to solve it. Thank you!

THE ERROR message:

[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------

[0]PETSC ERROR: Error in external library

[0]PETSC ERROR: Error in LAPACK subroutine steqr: info=0

[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.

[0]PETSC ERROR: Petsc Release Version 3.10.0, Sep, 12, 2018 

[0]PETSC ERROR: ./step-36 on a  named Pragalvs-MacBook-Air.local by pragalvkarki Tue Sep 10 15:29:22 2019

 

(Lot of unnecessary stuff (I think ) in between these error messages)

 

An error occurred in line <182> of file </Applications/deal.II.app/Contents/Resources/spack/src/dealii-v9.1.1/source/lac/slepc_solver.cc> in function

    void dealii::SLEPcWrappers::SolverBase::solve(const unsigned int, unsigned int *)

The violated condition was: 

    ierr == 0

Additional information: 

        An error with error number 76 occurred while calling a SLEPc function 

 

Thank you for your time,

Pragalv

[Wolfgang Bangerth]

Pragalv,
I've tried to run step-36 on my workstation and it works just fine. Are
you running in parallel? You might also want to try a different version
of PETSc/SLEPc -- I am using 3.7.4/3.7.3 for the two.

I also tried to find out what error 76 actually means. I *think* that it
is this error defined in include/petscerror.h:
#define PETSC_ERR_LIB 76 /* error in library called by PETSc */
This error code is, unfortunately, widely used. Here's the part of the
error message that gives more information:

> [0]PETSC ERROR: Error in external library
>
> [0]PETSC ERROR: Error in LAPACK subroutine steqr: info=0

This is not particularly useful. I've tried to find where that error
message is generated in PETSc or SLEPc, but am unable to find the
location -- maybe that was only added in versions between my 3.7.x and
your 3.10.x. You might want to look into this -- but generally, all it
means that the LAPACK function steqr has returned an error, and you
still have to find out why that happened...

I know that's not what you were looking for, but that's the best I can
suggest for the moment. Since the program works for me, I can't really
debug it. But it provides you an avenue: Try a different machine and/or
a different PETSc/SLEPc version and see whether that makes a difference
for you!

Best
W.


--
------------------------------------------------------------------------
Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[Pragalv Karki]

Dear Prof. Wolfgang,

                Thank you very much for your reply and insight. I will change the PETSc/SLEPc versions to 3.7.4/3.7.3 and see if that will solve the issue.