Module rustfst::semirings

Provides a trait that shall be implemented for all weights stored inside a wFST.

Structs

• BooleanWeight
  Boolean semiring: (&, |, false, true).
• GallicWeight
  UnionWeight of GallicWeightRestrict.
• GallicWeightLeft
  Product of StringWeightLeft and an arbitrary weight.
• GallicWeightMin
  Product of StringWeightRestrict and an arbitrary weight.
• GallicWeightRestrict
  Product of StringWeighRestrict and an arbitrary weight.
• GallicWeightRight
  Product of StringWeightRight and an arbitrary weight.
• IntegerWeight
  Probability semiring: (x, +, 0.0, 1.0).
• LogWeight
  Log semiring: (log(e^-x + e^-y), +, inf, 0).
• ProbabilityWeight
  Probability semiring: (x, +, 0.0, 1.0).
• ProductWeight
  Product semiring: W1 * W2.
• SemiringProperties
  Properties verified by the Semiring.
• StringWeightLeft
  String semiring: (longest_common_prefix, ., Infinity, Epsilon)
• StringWeightRestrict
  String semiring: (identity, ., Infinity, Epsilon)
• StringWeightRight
  String semiring: (longest_common_suffix, ., Infinity, Epsilon)
• TropicalWeight
  Tropical semiring: (min, +, inf, 0).
• UnionWeight
  Semiring that uses Times() and One() from W and union and the empty set for Plus() and Zero(), respectively. Template argument O specifies the union weight options as above.

Enums

• DivideType
  Determines direction of division.
• StringType
  Determines whether to use left or right string semiring. Includes a ‘restricted’ version that signals an error if proper prefixes/suffixes would otherwise be returned by Plus, useful with various algorithms that require functional transducer input with the string semirings.

Traits

• CompleteSemiring
  A semiring (S, ⊕, ⊗, 0, 1) is said to be complete if for any index set I and any family (ai)i ∈ I of elements of S, ⊕(ai)i∈I is an element of S whose definition does not depend on the order of the terms in the ⊕-sum. Note that in a complete semiring all weighted transducers are regulated since all infinite sums are elements of S. For more information : https://cs.nyu.edu/~mohri/pub/hwa.pdf
• ReverseBack
• Semiring
  The weight on an Fst must implement the Semiring trait. Indeed, the weight set associated to a Fst must have the structure of a semiring. (S, +, *, 0, 1) is a semiring if (S, +, 0) is a commutative monoid with identity element 0, (S, *, 1) is a monoid with identity element 1, * distributes over +, 0 is an annihilator for *. Thus, a semiring is a ring that may lack negation. For more information : https://cs.nyu.edu/~mohri/pub/hwa.pdf
• SerializableSemiring
• StarSemiring
  A complete semiring S is a starsemiring that is a semiring that can be augmented with an internal unary closure operation ∗ defined by a∗=⊕an (infinite sum) for any a ∈ S. Furthermore, associativity, commutativity, and distributivity apply to these infinite sums. For more information : https://cs.nyu.edu/~mohri/pub/hwa.pdf
• UnionWeightOption
• WeaklyDivisibleSemiring
  A semiring is said to be divisible if all non-0 elements admit an inverse, that is if S-{0} is a group. (S, +, *, 0, 1) is said to be weakly divisible if for any x and y in S such that x + y != 0, there exists at least one z such that x = (x+y)*z. For more information : https://cs.nyu.edu/~mohri/pub/hwa.pdf
• WeightQuantize