xsimplex
(Package: combinat) :
Generates all points on a (p,n) simplex lattice (i.e. a p-part
Generates all points on a p,n simplex lattice (i.e. a p-part composition of n). Each point is represented as x, a p-dimensional vector of nonnegative integers that sum to n. If argument "fun" is not null, applies a function given by the argument to each point. If simplify is FALSE, returns a list; else returns a vector or an array. "..." are passed unchanged to function given by argument fun, if any.
nsimplex
(Package: combinat) :
Computes the number of points on a (p, n)-simplex lattice
Computes the number of points on a (p, n)-simplex lattice; that is, the number of p-part compositions of n. This gives the number of points in the support space of a Multinomial(n, q) distribution, where p == length(q).
combn
(Package: combinat) :
Generate all combinations of the elements of x taken m at a time.
Generate all combinations of the elements of x taken m at a time. If x is a positive integer, returns all combinations of the elements of seq(x) taken m at a time. If argument "fun" is not null, applies a function given by the argument to each point. If simplify is FALSE, returns a list; else returns a vector or an array. "..." are passed unchanged to function given by argument fun, if any.
permn
(Package: combinat) :
Generates all permutations of the elements of x
Generates all permutations of the elements of x, in a minimal- change order. If x is a positive integer, returns all permutations of the elements of seq(x). If argument "fun" is not null, applies a function given by the argument to each point. "..." are passed unchanged to the function given by argument fun, if any.
providing 
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