[petsc-users] eps eigenvectors error

[Jose E. Roman]

El 08/04/2015, a las 06:40, siddhesh godbole escribió:

> hello 
> 
> i am trying to retrieve the solution after EPSSolve but i am unable to get the eigenvectors when i call EPSGetEigenpair or EPSGetEigenvector
> 
> i am getting following error
> 
> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
> [0]PETSC ERROR: Null argument, when expecting valid pointer
> [0]PETSC ERROR: Null Object: Parameter # 3
> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
> [0]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014 
> [0]PETSC ERROR: ./eps13D on a arch-linux2-c-debug named iitm by iitm Wed Apr  8 10:04:57 2015
> [0]PETSC ERROR: Configure options --download-mpich --download-f2cblaslapack=1
> [0]PETSC ERROR: #1 EPSGetEigenvector() line 488 in /home/iitm/Downloads/slepc-3.5.2/src/eps/interface/epssolve.c
> [0]PETSC ERROR: #2 main() line 266 in /home/iitm/Desktop/project/eps13D.c
> [0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint at mcs.anl.gov----------
> 
> 
> what could be the reason?
> 

EPSGetEigenvector() needs to receive one (or two) valid vector object, where it will place the requested eigenvector. In other words, you must create the vector yourself and pass it. See for instance ex7.c

Jose