Checks if the result of a norm used by the corresponding
NaN. These indicate that the previous application of the preconditioner generated an error. Sets a
KSPConvergedReason and returns if the
PC set a
ksp - the linear solver
beta - the result of the norm
Used to manage returning from
KSP solvers whose preconditioners have failed, possibly only a subset of MPI ranks, in some way.
It uses the fact that
KSP piggy-backs the collectivity of certain error conditions on the results of norms and inner products.