The writhing number is a standard measure of the global geometry of a closed space curve. It is an attempt to capture the physical phenomenon that a cord tends to form loops and coils when it is twisted. It attracted much attention after its relationship with the linking number, expressed by the following White Formula, was discovered independently by several researchers: We have developed an efficient algorithm to compute the writhing number of an input polygonal curve. It runs in near-linear time for most data in practice. A readme and a sample input data file are included in the download packages. |

Platform: Sun Solaris File size: 800 kb Download writhe.tar |
Platform: Linux Tar-ball file size: 970 kb Download linux_writhe.tar |

"Computing the writhing number of a polygonal knot,"
P. K. Agarwal, H. Edelsbrunner and Y. Wang, to appear in DCG, also
appeared in Syomposium on Discrete Algorithms, 2002. |

Writhe was developed by Yusu Wang. For more information, please see http://www.cs.duke.edu/~wys/writhe/ or contact Yusu Wang <wys@cs.duke.edu> |