strange behaviour with PetscViewerBinary on MATIS

Andreas Grassl Andreas.Grassl at
Thu Jul 23 10:08:26 CDT 2009

Jed Brown schrieb:
> You can put this in MatView_IS if you really need it, but I doubt it
> will actually be useful.  Unfortunately, you cannot change the domain
> decomposition with Neumann preconditioners, hence they will have limited
> use for solving a system with a saved matrix.  Why do you want to save
> the matrix, it's vastly slower and less useful than a function which
> assembles that matrix?

I assemble the Matrix by reading out from a data structure produced by a
proprietary program and just used this easy approach to compare the solvers on
different machines, where this program is not installed.

Since the implementation of the NN-preconditioner is suboptimal at all, I will
not waste much time on this issues and my post at the list was lead mostly by my

thanks for the explanation



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