public static IExampleSpace <TResult> MergeInternal <T, TResult>(
List <IExampleSpace <T> > exampleSpaces,
Func <List <T>, TResult> mergeValues,
ShrinkFunc <List <IExampleSpace <T> > > shrinkExampleSpaces,
MeasureFunc <List <IExampleSpace <T> > > measureMerge,
ImmutableHashSet <ExampleId> encounteredIds,
bool enableSmallestExampleSpacesOptimization,
bool isRoot)
{
IExampleSpace <TResult> GenerateNextExampleSpace(IEnumerable <IExampleSpace <T> > exampleSpaces, ImmutableHashSet <ExampleId> encounteredIds)
{
return(MergeInternal(
exampleSpaces.ToList(),
mergeValues,
shrinkExampleSpaces,
measureMerge,
encounteredIds,
enableSmallestExampleSpacesOptimization,
false));
}
var mergedId = exampleSpaces.Aggregate(
ExampleId.Primitive(exampleSpaces.Count()),
(acc, curr) => ExampleId.Combine(acc, curr.Current.Id));
var mergedValue = mergeValues(exampleSpaces.Select(es => es.Current.Value).ToList());
var mergedDistance = measureMerge(exampleSpaces);
var current = new Example <TResult>(
mergedId,
mergedValue,
mergedDistance);
var smallestExampleSpacesShrink = enableSmallestExampleSpacesOptimization && isRoot && exampleSpaces.Any(exampleSpace => exampleSpace.Subspace.Any())
? exampleSpaces
.Select(exampleSpace =>
{
var smallestExampleSpace = exampleSpace.Subspace.FirstOrDefault() ?? exampleSpace;
return(smallestExampleSpace);
})
.ToList()
: null;
var exampleSpaceCullingShrinks = shrinkExampleSpaces(exampleSpaces);
var subspaceMergingShrinks = exampleSpaces
.Select((exampleSpace, index) => LiftAndInsertSubspace(exampleSpaces, exampleSpace.Subspace, index))
.SelectMany(exampleSpaces => exampleSpaces);
var shrinks = TraverseUnencountered(
Enumerable.Concat(
smallestExampleSpacesShrink == null ? Enumerable.Empty <List <IExampleSpace <T> > >() : new[] { smallestExampleSpacesShrink }.AsEnumerable(),
Enumerable.Concat(exampleSpaceCullingShrinks, subspaceMergingShrinks)),
encounteredIds,
GenerateNextExampleSpace);
return(new ExampleSpace <TResult>(current, shrinks));
}
static IExampleSpace <TResult> JoinExampleSpaces(
IExampleSpace <T> leftExampleSpace,
IExampleSpace <TResult> rightExampleSpace,
Func <T, IGen <TResult> > selector,
GenParameters parameters)
{
var jointExampleSpace = rightExampleSpace.MapExamples(example => new Example <TResult>(
ExampleId.Combine(leftExampleSpace.Current.Id, example.Id),
example.Value,
leftExampleSpace.Current.Distance + example.Distance));
var boundLeftSubspace = leftExampleSpace.Subspace.SelectMany(leftExampleSubspace =>
BindSubspace(leftExampleSubspace, selector, parameters));
return(ExampleSpaceFactory.Create(
jointExampleSpace.Current,
Enumerable.Concat(boundLeftSubspace, rightExampleSpace.Subspace)));
}
