Before revision: The Dual Matrix Algorithm  , variations of which were proposed in A.
After revision: NP (search) problems allow easy correctness tests for solutions. Climbing algorithms allow also easy assessment of how close to yielding the correct answer is the configuration at any stage of their run. This offers a great flexibility, as how sensible is any deviation from the standard procedures can be instantly assessed. An example is the Dual Matrix Algorithm , variations of which were proposed in A.