[petsc-dev] strangness in Chebyshev estimate of eigenvalues

[Jed Brown]

Barry Smith <bsmith at mcs.anl.gov> writes:
>    This is the default behavior if one just creates a PetscRandom and uses it, so don't be going and setting seeds inside GAMG or Chebyshev.

You're right (my mistake), but the consequences are dangerous if the
user is holding a PetscRandom across calls to GAMG (or anything that
creates new PetscRandom instances).  The reason is that merely creating
a PetscRandom reseeds the global PRNG.  (What moron thought a global
seed was a good idea?)  Seems to me we should avoid drand48 always so we
don't disrupt the user's source of randomness (leading to really
confusing incorrect results).  We could use the non-disastrous
drand48_r, but it's a GNU extension so we'd need an alternative anyway.

If Matt changes "rander48" to the rand48_r (or erand48_r) interface,
then we'd be okay.  This would also remove the internal variables that
Matt forget to make static.
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