abu-parser ¶This program is a probabilistic adaptive bottom-up parser. Its main purpose is the synthesis of a PCFG based on a bottom-up template grammar. The synthesis method is iterative determinization of a top-down template grammar generated from a bottom-up template grammar. Compared to a top-down template grammar, a bottom-up template grammar makes it possible to specify parsing behavior in a more convenient way. The bottom-up parser operates in parse unit mode and does not support parsing a single stream of terminal symbols.
As opposed to the probabilistic adaptive top-down parser atd-parser (see atd-parser), the bottom-up parser adaptively processes training parse units to increase the probability of a source PCFG intended for parsing in the bottom-up direction rather than the probability of a derived PCFG intended for parsing in the top-down direction.
For that, a top-down template grammar used by the bottom-up parser contains references to the productions of a source PCFG inferred from a bottom-up template grammar.
A top-down template grammar supplied to the bottom-up parser requires conversion from a bottom-up template grammar by the rege-markup-cfg tool, optionally by the rege-vit tool, and by the rege-bottom-up tool.
See Bottom-Up Template Grammar, for more information on conversion steps.