[petsc-users] Precision Problem in computing Eigenvalue
Jose E. Roman
jroman at dsic.upv.es
Mon Jan 5 05:19:14 CST 2015
El 05/01/2015, a las 11:28, Ajay Manwani escribió:
> Hello, Thank you very much for your reply.
> i installed PETSC in quad and complex mode without C++,(./configure --download-mpich --with-fc-gfortran --with-cc=gcc --with-cxx=g++ --with-scalar-type=complex --with-precision=__float128 --download-f2cblaslapack )
>
> It worked fine but problem is eigenvalues we get by PEPSolve() are correct and then as i use PEPGetPair(), i get absurd values.
> I want to write eigenvalues and eigenpairs to a text file hence i need to use PEPGetEigenpair command
>
>
> --Ajay
In quad precision you need to explicitly cast to double in printf statements, see e.g.
http://www.grycap.upv.es/slepc/documentation/current/src/eps/examples/tutorials/ex1.c.html
Is this your problem? Otherwise, send the code excerpt where you extract and print eigenpairs.
Jose
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