private List <Probable <Sentence> > GoOneStep(Probable <Sentence> swp, int remainingDepth, int limit = int.MaxValue)
{
var start = new Probable <Sentence>(swp.Probability, new Sentence());
var results = new List <Probable <Sentence> > {
start
};
foreach (var word in swp.Value)
{
if (results.Count > limit)
{
// have to return empty here, since we don't have complete sentences
return(new List <Probable <Sentence> >());
}
if (word.IsNonterminal)
{
results = StepNonterminal(results, word, remainingDepth);
}
else
{
results = StepTerminal(results, word);
}
}
return(results);
}
/// <summary>
/// Returns all the sentences (with their probabilities) that can be generated up to a certain depth
/// </summary>
/// <returns></returns>
public List <Probable <Sentence> > ProduceToDepth(int depth, int limit = int.MaxValue)
{
var start = new Sentence {
this.Start
};
var intermediate = new List <Probable <Sentence> > [depth + 1];
var startSWP = new Probable <Sentence>(1.0, start);
intermediate[0] = new List <Probable <Sentence> > {
startSWP
};
int count = 0;
for (int i = 0; i < depth; i++)
{
if (count >= limit)
{
break;
}
var prev = intermediate[i];
var next = new List <Probable <Sentence> >();
intermediate[i + 1] = next;
foreach (var swp in prev)
{
if (!swp.Value.OnlyTerminals())
{
var steps = GoOneStep(swp, depth - i, limit);
if (steps.Count == 0)
{
count = limit;
}
next.AddRange(steps);
count += steps.Count;
}
if (count >= limit)
{
break;
}
}
}
var results = new List <Probable <Sentence> >();
// TODO: terrible :(
var resultDict = new Dictionary <string, Probable <Sentence> >();
foreach (var step in intermediate)
{
if (step == null)
{
continue;
}
foreach (var swp in step)
{
if (!swp.Value.OnlyTerminals())
{
continue;
}
Probable <Sentence> psentence;
var stringrep = swp.Value.ToString();
if (!resultDict.TryGetValue(stringrep, out psentence))
{
psentence = new Probable <Sentence>(0.0, swp.Value);
resultDict[stringrep] = psentence;
}
psentence.Probability += swp.Probability;
// results.Add(swp);
}
}
return(resultDict.Values.ToList());
}