# Overview

W. D. Gillam. ( http://www.math.columbia.edu/~wgillam/hfk ) Modifications and extensions to the original code were written by Marc Culler, who was granted permission to modify and distribute the derived version by the original authors. However, this permission is not transferable, and all rights to the code belong to Baldwin and Gillam. =======================================================

The file hfk_class.cpp defines a C++ class whose objects are constructed from two permutations describing a grid projection of a link. The constructor for this class calculates the ranks of the non-zero groups of the Heegaard Floer link homology, and saves them as data in the object.

The file hfkdemo.cpp gives an example of how to use this class in a C++ program. To compile:

g++ -o hfkdemo -O3 hfkdemo.cpp

The directory hfk contains a python package which encapsulates the hfk class. It can be used as a command line calculator from within the python intepreter, it can be used in a simple python script for doing batch computations, or as part of a larger python program.

To install the python package as root: python setup.py install

To install in your home directory: python setup.py install --home ~

(Make sure ~/bin is in your PATH and ~/lib/python is in your PYTHON_PATH).

A sample session using the python interpreter is shown below:

\$ python Python 2.3 (#3, Dec 11 2006, 10:05:13) [GCC 3.2.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from hfk import * >>> D = HFK([3,5,6,9,1,2,10,7,4,8,0],[6,7,10,2,4,0,8,3,9,1,5]) >>> D

. . . X . . O . . . . . . . . . X . O . . . . . . . . . X . . . O . . O . . . . . . X . . X . . O . . . . . . O . X . . . . . . . . . . . . . . . . O . X . . . O . . . X . . . . . . . X . . . . O . . O . . . . . . X . . X . . . . O . . . . .
>>> D.HFK_ranks()
Constructing vertices ...  100% Number of vertices: 14377
Constructing edges ...  100% Number of edges: 46703
Reducing graph ... 100%

0 0 0 0 3 0 0 0 10 0 0 0 13 0 0 0 10 0 0 0 3 0 0 0 0
>>>