Test ing Parallel Simulators for Two - Dimensional Lattice - Gas Automata * Richard Squier

We describe a test method for lattice-gas automata of the type introduced by Fr isch , Hasslacher , and P omeau. The test met hod consist s of inserting test patterns into the initial state of the auto maton and using a graphics display to detect errors. The test pattern s are care fully construct ed limit cycles tha t are disrupted by err ors occurr ing at any level of t he simulator system. T he pat tern s can be run ind ependently to test t he sys te m for debugging purposes, or they can be run as sub-simulations embedded in a larger la t tice-gas simulat ion to det ect fault s at runtime. We describ e the use of this metho d on a prototype par allel machine for lat t ice-gas simulat ions, and discuss the range of systems that can make use of this type of test method. T he test patterns det ect all significant one-bit err ors. We include experimental resul ts that indica te mult ip le-bit err ors are unli kely to escape det ection .