Package nltk :: Module grammar :: Class WeightedProduction

type WeightedProduction

                             object --+    
                                      |    
                             Production --+
                                          |
                         object --+       |
                                  |       |
     probability.ProbabilisticMixIn --+   |
                                      |   |
probability.ImmutableProbabilisticMixIn --+
                                          |
                                         WeightedProduction

A probabilistic context free grammar production. PCFG WeightedProductions are essentially just Productions that have probabilities associated with them. These probabilities are used to record how likely it is that a given production will be used. In particular, the probability of a WeightedProduction records the likelihood that its right-hand side is the correct instantiation for any given occurance of its left-hand side.

See Also: Production

Instance Methods

[hide private]

__init__(self, lhs, rhs, **prob)
Construct a new WeightedProduction. source code

string

__str__(self)
Returns: A verbose string representation of the Production. source code

boolean

__eq__(self, other)
Returns: true if this Production is equal to other. source code

__ne__(self, other)

source code

int

__hash__(self)
Returns: A hash value for the Production. source code

Inherited from Production: __cmp__, __len__, __repr__, is_lexical, is_nonlexical, lhs, rhs

Inherited from probability.ImmutableProbabilisticMixIn: set_logprob, set_prob

Inherited from probability.ProbabilisticMixIn: logprob, prob

Instance Variables

[hide private]

Inherited from Production (private): _lhs, _rhs

Method Details

[hide private]

init(self, lhs, rhs, **prob)
(Constructor)

source code

Construct a new WeightedProduction.

Parameters:

lhs (Nonterminal) - The left-hand side of the new WeightedProduction.
rhs (sequence of (Nonterminal and (terminal))) - The right-hand side of the new WeightedProduction.
prob - Probability parameters of the new WeightedProduction.

Overrides: probability.ProbabilisticMixIn.__init__