[petsc-dev] MatTransposeMatMult

[Barry Smith]

  Send the runable case so that we can determine the cause of the slow down and find possible cures. It could be that the "optimized" version was optimized for a particular size of problems or matrix structure.

   Barry

> On Sep 20, 2017, at 4:32 PM, Jed Brown <jed at jedbrown.org> wrote:
> 
> I have a simple SeqAIJ example where MatTransposeMatMult is 30x slower
> than MatTranspose followed by MatMatMult.  This is embarrassing when
> people try to compare performance.  Are there any cases where these
> custom implementations provide value rather than just confusing people
> or turning them away from PETSc?