Added check in sa.py for an all zero coarsest level operator
Added check in sa.py for an all zero coarsest level operator

huahbo/pyamg,kidaa/pyamg,kidaa/pyamg,kidaa/pyamg,pyamg/pyamg,huahbo/pyamg,huahbo/pyamg,pyamg/pyamg,pyamg/pyamg,kidaa/pyamg,huahbo/pyamg