[petsc-dev] strangness in Chebyshev estimate of eigenvalues

[Jed Brown]

Barry Smith <bsmith at mcs.anl.gov> writes:
>   Of course, as always, with different number of processes one will
>   get different results, even with Jacobi + Chebyshev because the
>   random numbers generated will be different with different number of
>   processes, is this important?

I can't think of a way to get a "noisy" vector deterministically and
independent of the distribution.  We could use a hash of the global row
index, which would help with debugging in the sense that we could read
in a stored matrix on a different number of cores and get the same
Chebyshev/Jacobi estimates.  I have a minor preference for this instead
of random initialization, but it wouldn't help with most discretizations
because the distribution usually changes the ordering.
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