David, Actually, I just looked around and didn't see much interesting and cleanly available along this line so I just wrote a digamma function.
See https://issues.apache.org/jira/browse/MATH-267 for a tar file containing an implementation with test cases. I went ahead and copyrighted this for apache use. It contains source, comments and test values derived from mathematica. In the process, I discovered that the R implementation of digamma is really crappy for medium small positive values of x. On Sat, May 23, 2009 at 2:26 PM, David Hall <d...@cs.stanford.edu> wrote: > "Share" is too strong. He released a number of functions in the > library I linked to, and the only requirement of the license seems to > be we maintain the copyright notice and say what we changed: > > /* Copyright (c) 1995-2003 by Radford M. Neal > * > * Permission is granted for anyone to copy, use, modify, or distribute > this > * program and accompanying programs and documents for any purpose, > provided > * this copyright notice is retained and prominently displayed, along with > * a note saying that the original programs are available from Radford > Neal's > * web page, and note is made of any changes made to the programs. The > * programs and documents are distributed without any warranty, express or > * implied. As the programs were written for research purposes only, they > have > * not been tested to the degree that would be advisable in any important > * application. All use of these programs is entirely at the user's own > risk. > */ > > I can also just email him directly. > > -- David > > > On Sat, May 23, 2009 at 2:22 PM, Ted Dunning <ted.dunn...@gmail.com> > wrote: > > Avoid Numerical Recipes if you want to avoid license issues. Their > > publisher has a strong history of being very strict about their > > interpretation of what they think they own. > > > > If Radford Neal has an implementation that he would share, I would count > > that as a great contribution. > > > > On Sat, May 23, 2009 at 2:09 PM, David Hall <d...@cs.stanford.edu> > wrote: > > > >> > >> Alternatively, I can try to track down a book (Numerical Recipes?) > >> with pseudocode. > > > > > > > > > > -- > > Ted Dunning, CTO > > DeepDyve > > > -- Ted Dunning, CTO DeepDyve 111 West Evelyn Ave. Ste. 202 Sunnyvale, CA 94086 http://www.deepdyve.com 858-414-0013 (m) 408-773-0220 (fax)
