Parallelism and Dependence • No dependence

• Hints express likely rather than definite parallelism • bop ppr { code} • PPR means possibly parallel region • the PPR block may be parallel with the code after the PPR block • bop ordered { code} • the ordered block should be run one task at a time and in the sequential order • Sequential equivalence • a parallel execution is allowed if its results are the same as sequential execution • incorrect hints may lose parallelism but won’t affect result • no non-determinism, no dead/live lock, no parallel debuggin