protected static PairResult MatchOneRow(T todo, object objshr)
{
MatchShared shared = (MatchShared)objshr;
BestScore <T> one_to_all = new BestScore <T>();
// start by looking at all results for one's row
foreach (T two in shared.twos)
{
double score = shared.comparisons.Evaluate(new TwoTuple <T, T>(todo, two), shared);
one_to_all.Improve(score, two);
}
if (one_to_all.payload == null || one_to_all.payload.Equals(default(T)))
{
// no more results! Return empty match.
shared.ones = new SkipEnumerable <T>(shared.ones, todo);
return(new PairResult(double.NegativeInfinity, todo, default(T)));
}
// Now look at all other entries in that column
BestScore <T> match_to_others = new BestScore <T>(one_to_all.score, todo);
foreach (T one in shared.ones)
{
if (!one.Equals(todo))
{
double score = shared.comparisons.Evaluate(new TwoTuple <T, T>(one, one_to_all.payload), shared);
match_to_others.Improve(score, one);
}
}
if (match_to_others.payload.Equals(todo))
{
// remove this row and column
shared.ones = new SkipEnumerable <T>(shared.ones, todo);
shared.twos = new SkipEnumerable <T>(shared.twos, one_to_all.payload);
return(new PairResult(one_to_all.score, todo, one_to_all.payload));
}
else
{
// First do the row we found!
shared.matches.Evaluate(match_to_others.payload, shared);
// Then do this one again!
return(MatchOneRow(todo, shared));
}
}
// Find the best matches, ensuring one entry for every element in ones
public static IEnumerable <PairResult> LeftMatch(IEnumerable <T> ones, IEnumerable <T> twos, MatchScorer scorer, object objshr)
{
MatchShared shared = new MatchShared();
shared.objshr = objshr;
shared.matches = new Memoizer <T, PairResult>(MatchOneRow);
shared.comparisons = new Memoizer <TwoTuple <T, T>, double>(MatchComparison);
shared.scorer = scorer;
shared.ones = ones;
shared.twos = twos;
foreach (T one in ones)
{
shared.matches.Evaluate(one, shared);
}
return(shared.matches.Results.Values);
}
protected static double MatchComparison(TwoTuple <T, T> onetwo, object objshr)
{
MatchShared shared = (MatchShared)objshr;
return(shared.scorer(onetwo.one, onetwo.two, shared.objshr));
}
