// Use the label to create a chain of hmms.
// If model set only has one hmm, no need to use labels, simply assign the only hmm.
func (ms *Set) chainFromAssigner(obs model.Obs, assigner Assigner) (*chain, error) {
var hmms []*Net
var fos model.FloatObsSequence
switch o := obs.(type) {
case model.FloatObsSequence:
fos = o
case *model.FloatObsSequence:
fos = *o
default:
return nil, fmt.Errorf("obs must be of type model.FloatObsSequence, found type %s which is not supported",
reflect.TypeOf(obs))
}
if len(fos.ValueAsSlice()) == 0 {
return nil, fmt.Errorf("obs sequence has no data")
}
if assigner == nil && ms.size() == 1 {
hmms = append(hmms, ms.Nets[0])
if glog.V(3) {
glog.Warningf("assigner missing but model set has only one hmm network - assigning model [%s] to chain", ms.Nets[0].Name)
}
} else if assigner == nil {
return nil, fmt.Errorf("need assigner to create hmm chain if model set is greater than one")
} else {
// Get the labeler and check that it is of type SimpleLabeler
// otherwise return error.
labeler, ok := obs.Label().(model.SimpleLabel)
if !ok {
return nil, fmt.Errorf("labeler must be of type model.SimpleLabel, found type %s which is not supported",
reflect.TypeOf(obs.Label()))
}
// Now we need to assign hmms to the chain.
// We will use the sequence of labels to lookup the models by name.
labels := strings.Split(labeler.String(), ",")
if len(labels) == 1 && len(labels[0]) == 0 {
return nil, fmt.Errorf("no label found, can't assign models")
}
modelNames := assigner.Assign(labels)
glog.V(5).Infof("obsid:%s, labels:%v", obs.ID(), labels)
glog.V(5).Infof("obsid:%s, models:%v", obs.ID(), modelNames)
for _, name := range modelNames {
h, ok := ms.net(name)
if !ok {
return nil, fmt.Errorf("can't find model for name [%s] in set - assignment failed", name)
}
hmms = append(hmms, h)
}
}
nq := len(hmms)
if nq == 0 {
return nil, fmt.Errorf("the assigner returned no models")
}
ch := &chain{
hmms: hmms,
nq: nq,
ns: make([]int, nq, nq),
obs: obs,
vectors: fos.Value().([][]float64),
nobs: len(fos.Value().([][]float64)),
ms: ms,
}
for k, hmm := range hmms {
if hmm.A.Shape[0] > ch.maxNS {
ch.maxNS = hmm.A.Shape[0]
}
ch.ns[k] = hmm.A.Shape[0]
}
ch.alpha = narray.New(ch.nq, ch.maxNS, ch.nobs)
ch.beta = narray.New(ch.nq, ch.maxNS, ch.nobs)
ch.computeLikelihoods()
// Validate.
// Can't have models with transitions from entry to exit states
// at the beginning or end of a chain.
if isTeeModel(hmms[0]) {
return nil, fmt.Errorf("the first model in the chain can't have a transition from entry to exit states - model name is [%s] with id [%d]", hmms[0].Name, hmms[0].id)
}
if isTeeModel(hmms[nq-1]) {
return nil, fmt.Errorf("the last model in the chain can't have a transition from entry to exit states - model name is [%s] with id [%d]", hmms[nq-1].Name, hmms[nq-1].id)
}
return ch, nil
}
