public static IDiscreteDistribution <T> ToWeighted <T>([NotNull] this IEnumerable <T> items,
[NotNull] IEnumerable <int> weights)
{
var list = items.ToList();
return(WeightedInteger.Distribution(weights)
.Select(i => list[i]));
}
public static IDiscreteDistribution <TR> Select <TA, TR>([NotNull] this IDiscreteDistribution <TA> d,
[NotNull] Func <TA, TR> projection)
{
var dict = d.Support()
.GroupBy(projection, d.Weight)
.ToDictionary(g => g.Key, g => g.Sum());
var rs = dict.Keys.ToList();
return(Projected <int, TR> .Distribution(
WeightedInteger.Distribution(
rs.Select(r => dict[r])),
i => rs[i]));
}
