3.4.1 Memory-efficient 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 [12]. 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. This option can be used in combination with MAP inference (-m or -a) or MCMC inference (-p, -ms or -simtp).

If the -lazy option 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.