Stability | experimental |
---|---|
Maintainer | byorgey@cis.upenn.edu |
An interpretation of species as exponential generating functions, which count labeled structures.
Documentation
labeled :: EGF -> [Integer]Source
Extract the coefficients of an exponential generating function as
a list of Integer
s. Since EGF
is an instance of Species
, the
idea is that labeled
can be applied directly to an expression
of the species DSL. In particular,
is the
number of labeled labeled
s !!
ns
-structures on an underlying set of size n
(note that
is guaranteed to be an infinite list).
For example:
labeled
s
> take 10 $ labeled octopi [0,1,3,14,90,744,7560,91440,1285200,20603520]
gives the number of labeled octopi on 0, 1, 2, 3, ... 9 labels.