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3.4.1 Memory-efficient MAP inference

MAP inference involves the propositionalization of the knowledge base and the running of a satisfiability solver MaxWalkSat [2] on all of the resulting clauses. This can be done with less memory (due to the typical sparseness of relational domains) with the LazySat algorithm. Most clauses are trivially satisfied and do not need to be held in memory. By using the -lazy option, the memory-efficient variant is run.

If the MaxWalkSat version is chosen (i.e. -lazy is omitted), then Alchemy determines if it can be fully instantiated based on the amount of main memory. Alternatively, the user can define a maximum limit of memory to be used, in kilobytes, with the option -mwsLimit. Alchemy then uses this limit to determine which version should be used.


Marc Sumner 2006-05-03