Path-Oriented DEcision Making [Goel, 1981]
(1)?Assign all Primary Inputs (PI) to the value "don't care" (?).
(2)?Given an output signal and a desired value for the output, trace a path to the PIs to obtain a PI assignment.
(3) Simulate the PI vector to see if it sets up the desired value on the output. If so, terminate.
(4)?If the opposite value is set, assign an opposite value to the PI and re-simulate. If desired value is set, terminate.
(5) If the output remains unspecified, repeat the path tracing to set another PI, as necessary.
??Procedure continues until either:
???A successful PI assignment has been found (circuits not equivalent).
???All possible PI assignments have been exhausted.