Data.CRF.Chain1.Constrained.Model

Internal implementation of the CRF model.

Documentation

newtype FeatIx

A feature index. To every model feature a unique index is assigned.

Constructors

FeatIx

Fields

unFeatIx :: Int

Instances

Eq FeatIx

Ord FeatIx

Show FeatIx

Unbox FeatIx

Binary FeatIx

Vector Vector FeatIx

MVector MVector FeatIx

data Model

The model is actually a map from features to their respective potentials, but for the sake of efficiency the internal representation is more complex.

Constructors

Model

Fields

values :: Vector Double

Value (potential) of the model for feature index.

ixMap :: Map Feature FeatIx

A map from features to feature indices

r0 :: AVec Lb

A default set of labels. It is used on sentence positions for which no constraints are assigned.

sgIxsV :: Vector FeatIx

Singular feature index for the given label. Index is equall to -1 if feature is not present in the model.

obIxsV :: Vector (AVec LbIx)

Set of labels for the given observation which, together with the observation, constitute an observation feature of the model.

prevIxsV :: Vector (AVec LbIx)

Set of ,,previous'' labels for the value of the ,,current'' label. Both labels constitute a transition feature present in the the model.

nextIxsV :: Vector (AVec LbIx)

Set of ,,next'' labels for the value of the ,,current'' label. Both labels constitute a transition feature present in the the model.

Instances

Binary Model

mkModel :: Ob -> Lb -> [Feature] -> Model

Construct the model from the list of features. All parameters will be set to 0. There can be repetitions in the input list. We assume that the set of labels is of the {0, 1, .. lbMax} form and, similarly, the set of observations is of the {0, 1, .. obMax} form.

valueL :: Model -> FeatIx -> LogFloat

Model potential defined for the given feature interpreted as a number in logarithmic domain.

featToIx :: Model -> Feature -> Maybe FeatIx

Determine index for the given feature.

featToJustIx :: Model -> Feature -> FeatIx

Determine index for the given feature. Throw error when the feature is not a member of the model.

featToJustInt :: Model -> Feature -> Int

Determine index for the given feature and return it as an integer. Throw error when the feature is not a member of the model.

sgValue :: Model -> Lb -> LogFloat

Potential value (in log domain) of the singular feature with the given label. The value defaults to 1 (0 in log domain) when the feature is not a member of the model.

sgIxs :: Model -> [LbIx]

List of labels which can be located on the first position of a sentence together with feature indices determined by them.

obIxs :: Model -> Ob -> AVec LbIx

List of labels which constitute a valid feature in combination with the given observation accompanied by feature indices determined by these labels.

nextIxs :: Model -> Lb -> AVec LbIx

List of ,,next'' labels which constitute a valid feature in combination with the ,,current'' label accompanied by feature indices determined by ,,next'' labels.

prevIxs :: Model -> Lb -> AVec LbIx

List of ,,previous'' labels which constitute a valid feature in combination with the ,,current'' label accompanied by feature indices determined by ,,previous'' labels.