1. AddOne Action performance beats new() performance up to scale 10⁴. At higher scales performance between the two is roughly equal.
2. Good AddOne Action scaling performance through scale 10⁶. Much better than Map.

Mutable hash sets based by default on F# structural “hash” and (=) functions. Implemented via a hash table and/or Dictionary. Be aware there may be multiple bindings for any given hash key.

Constructors:


new : unit -> HashMultiMap<'Key,'Value>
new : comparer:IEqualityComparer<'Key> * size:int -> HashMultiMap<'Key,'Value>
new : entries:seq<'Key * 'Value> -> HashMultiMap<'Key,'Value>
new : size:int -> HashMultiMap<'Key,'Value>


1. As would be expected good Init and AddOne Action performance through scale 10⁶.
2. At scale 10⁶ Init Action significantly outperforms AddOne Action.

LazyLists are possibly-infinite, cached sequences. See also IEnumerable/Seq for uncached sequences. Calling “get” on the same lazy list value you will keep getting the same (cached) result. LazyLists normally involve delayed computations without side-effects, and calling “get” may cause these computations to be executed. The results of these computations are cached – evaluations will be performed only once for each element of the lazy list. This is different to IEnumerable/Seq where recomputation happens each time an enumerator is created and the sequence traversed. LazyLists can represent cached potentially-infinite computations. Because they are cached they may cause memory leaks if some part of your code maintains a live reference to the head of an infinite or very large lazy list while iterating it, or if a reference is maintained after the list is no longer required. Although lazy lists are an abstract type you may pattern match against them using the LazyList.Cons and LazyList.Nil active patterns. These may force the computation of elements of the list.

–from original Microsoft Research documentation

Constructors:

LazyList has no constructors. Instantiate a LazyList through one of the LazyList Module operators.