Nondeterministic

A parallel algorithm is nondeterministic if its behavior might vary from run to run when the input is the same. It is deterministic if it always does the same thing on the same input, no matter how the instructions are scheduled on the multicore computer. A parallel algorithm that is intended to be deterministic may nevertheless act nondeterministically, however, if it contains a difficult-to-diagnose bug called a determinacy race.