unicycle, a C code which carries out some operations on permutations with a single cycle.

A permutation with a single cycle is a permutation P of N objects with the property that, for every object, it takes exactly N applications of P to restore an object to its original value.

Another way to think of this is that a permutation with a single cycle can be symbolized by a bracelet with N beads; the action of the permutation is to rotate the bracelet one position.

A permutation with a single cycle can be written in sequence form. Assuming the objects are labeled 1 through N, we start with 1, followed by P(1), followed by P(P(1)), and so on. Thus, the sequence (1,4,2,5,3) indicates the permutation which maps 1->4, 2->5, 3->1, 4->2, and 5->3.

A permutation with a single cycle is sometimes called a "cyclic permutation", but this term is also used with other meanings. Hence, we will affectionately call these objects "unicycles".


The information on this web page is distributed under the MIT license.


unicycle is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:


combo, a C code which includes many combinatorial routines.

subset, a C code which generates, ranks and unranks various combinatorial objects.

Source Code:

Last revised on 12 August 2019.