// Graphviz visuallizes the current internal topology of the Builder.
func (b *Builder) Graphviz(w io.Writer) {
fmt.Fprintln(w, "digraph {")
fmt.Fprintln(w, " // lexical transitions")
for p, es := range b.transitions {
if es != nil {
for xqw := range es.Range() {
x, qw := word.Id(xqw.Key), xqw.Value
fmt.Fprintf(w, " %d -> %d [label=%q]\n", p, qw.State, fmt.Sprintf("%s : %g", b.vocab.StringOf(x), qw.Weight))
}
}
}
fmt.Fprintln(w, " // back-off transitions")
for i, s := range b.backoff {
fmt.Fprintf(w, " %d -> %d [label=%q,style=dashed]\n", i, s.State, fmt.Sprintf("%g", s.Weight))
}
fmt.Fprintln(w, "}")
}
// link links each state p to the first state q with at least one
// lexical transition along p's back-off chain.
func (b *Builder) link() {
// Children of _STATE_EMPTY directly backs off the _STATE_EMPTY.
for xqw := range b.transitions[_STATE_EMPTY].Range() {
q := xqw.Value.State
if q != STATE_NIL {
b.backoff[q].State = _STATE_EMPTY
}
}
// States are created with STATE_NIL as the default back-off. Except
// for _STATE_EMPTY, having a STATE_NIL back-off means the back-off
// is yet to be computed.
for i, es := range b.transitions[_STATE_EMPTY+1:] {
if es != nil {
for xqw := range es.Range() {
p, x, q := StateId(i+1), word.Id(xqw.Key), xqw.Value.State
if q != STATE_NIL {
b.linkTransition(p, x, q)
}
}
}
}
}