# fwd.combn: Generate all combinations of elements of x taken m at a time In forward: Forward search

## Description

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. Optional arguments `...` are passed unchanged to the function given by argument `fun`, if any.

## Usage

 ```1 2``` ```fwd.combn(x, m, fun = NULL, simplify = TRUE, ...) fwd.nCm(n, m, tol = 1e-08) ```

## Arguments

 `x` a vector or a single value. `n` a positive integer. `m` a positive integer. `fun` a function to be applied to each combination. `simplify` logical, if `TRUE` returns a vector or an array, otherwise a list. `tol` optional, tolerance value. `...` optional arguments passed to `fun`.

## Value

Returns a vector or an array if `simplify = TRUE`, otherwise a list.

## Note

Renamed by Kjell Konis for inclusion in the Forward Library 11/2002

Scott Chasalow

## References

Nijenhuis, A. and Wilf, H.S. (1978) Combinatorial Computers and Calculators. NY: Academic Press.

## Examples

 ```1 2 3 4 5 6 7``` ```fwd.combn(letters[1:4], 2) fwd.combn(10, 5, min) # minimum value in each combination # Different way of encoding points: fwd.combn(c(1,1,1,1,2,2,2,3,3,4), 3, tabulate, nbins = 4) # Compute support points and (scaled) probabilities for a # Multivariate-Hypergeometric(n = 3, N = c(4,3,2,1)) p.f.: table(t(fwd.combn(c(1,1,1,1,2,2,2,3,3,4), 3, tabulate, nbins=4))) ```

forward documentation built on May 29, 2017, 3:55 p.m.