| permute {lmPerm} | R Documentation |
Permutation Generation
Description
Generates permutations a pair at a time.
Usage
permute(N=4,K=1,initialize=0)
Arguments
N |
The number of elements in the permutation vector. The elements are numbered 1:N |
K |
The number of exchange pairs to be returned at each access |
initialize |
Set to 1 to initialize. Set to 0 for additional pairs. |
Details
On first call, set initialize to 1. On subsequent accesses, initialize should be 0. The function returns at most K exchange pairs at each access. The function should be repeatedly called until result is false.
The function returns a list.
Value
result |
Returns false when the last permutation has been generated or a failure has occurred. Returns true for success and at most K new pairs in vec. |
N |
The input parameter |
K |
The input parameter |
vec |
A 2*K vector of element numbers to be exchanged – permutations may be obtained by successively applying these pairs. |
initialize |
Always returns 1 |
count |
The number of pairs in vec. It may be less than K for the final set. |
Note
This is the minimum time and effort routine. It is used for Exact permutation calculations. The present function is a wrapper for the C code and may be useful for other purposes. The code follows Reingole and Nievergelt (1977).
Author(s)
Bob Wheeler rwheeler@echip.com
References
- Reingold, E.M., Nievergelt, J., and Deo, N. (1977)
Combinatorial Algorithms Theory and Practice. Prentice Hall, New Jersey. p170.