crf.nll {CRF} | R Documentation |
Calculate CRF negative log likelihood
Description
Calculate the negative log likelihood of CRF model
Usage
crf.nll(
par,
crf,
instances,
node.fea = NULL,
edge.fea = NULL,
node.ext = NULL,
edge.ext = NULL,
infer.method = infer.chain,
...
)
Arguments
par |
The parameter vector of CRF |
crf |
The CRF |
instances |
The training data matrix of CRF model |
node.fea |
The list of node features |
edge.fea |
The list of edge features |
node.ext |
The list of extended information of node features |
edge.ext |
The list of extended information of edge features |
infer.method |
The inference method used to compute the likelihood |
... |
Extra parameters need by the inference method |
Details
This function calculates the negative log likelihood of CRF model as well as the gradient. This function is intended to be called by optimization algorithm in training process.
In the training data matrix instances
, each row is an instance and
each column corresponds a node in CRF.
The variables node.fea
, edge.fea
, node.ext
, edge.ext
are lists of length equal to the number of instances, and their elements are
defined as in crf.update
respectively.
Value
This function will return the value of CRF negative log-likelihood.