optimized complex number kernel

Satish Balay balay at mcs.anl.gov
Wed Dec 2 11:09:50 CST 2009

The performance difference between c/c++ kernels and fortran kernels -
or c-complex/c++-complex can be compiler specific. You can build all
relavent versions [each with a different PETSC_ARCH] and see if it
makes a difference for you code.

The relavent configure options are:
--with-fortran-kernels=generic [default 'none']
--with-clanguage=cxx [or default 'c']
--with-scalar-type=complex [default 'real']


On Wed, 2 Dec 2009, Craig Tanis wrote:

> Hi,
> The Petsc 3 manual (pdf)mentions using an optimized fortran kernel for complex numbers, that somehow uses the same C interface.  It refers to a document on how to build these kernels, but that document does not appear to be in the tarball (or on the anl.gov website).
> Furthermore, the FAQ on the website only mentions C and C++ in the section on complex number performance...
> If someone could clarify what was possible, and where to look for more information, that would be great!
> thanks,
> Craig

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