ReadOnlyCollection <Tuple <TNewKey, Tuple <IIndex <K>, VectorConstruction> > > IIndexBuilder.GroupBy <K, TNewKey>(IIndex <K> index, Func <K, TNewKey> keySel, VectorConstruction vector)
{
IIndexBuilder builder = (IIndexBuilder)this;
LinearIndex.windows <K, TNewKey> windows336 = new LinearIndex.windows <K, TNewKey>();
ReadOnlyCollection <K> keys = index.Keys;
IEnumerable <Tuple <M1, IEnumerable <M0> > > tuples1 = SeqModule.GroupBy <K, TNewKey>((Func <M0, M1>)keySel, (IEnumerable <M0>)keys);
IEnumerable <Tuple <TNewKey, IEnumerable <K> > > tuples2 = (IEnumerable <Tuple <TNewKey, IEnumerable <K> > >)SeqModule.Choose <Tuple <TNewKey, IEnumerable <K> >, Tuple <TNewKey, IEnumerable <K> > >((Func <M0, FSharpOption <M1> >)windows336, (IEnumerable <M0>)tuples1);
return(System.Array.AsReadOnly <Tuple <TNewKey, Tuple <IIndex <K>, VectorConstruction> > >((Tuple <TNewKey, Tuple <IIndex <K>, VectorConstruction> >[])ArrayModule.OfSeq <Tuple <TNewKey, Tuple <IIndex <K>, VectorConstruction> > >((IEnumerable <M0>)SeqModule.Map <Tuple <TNewKey, IEnumerable <K> >, Tuple <TNewKey, Tuple <IIndex <K>, VectorConstruction> > >((Func <M0, M1>) new LinearIndex.DeedleIndicesIIndexBuilderGroupBy <K, TNewKey>(index, vector, builder), (IEnumerable <M0>)tuples2))));
}
