-------- Original Message -------- Subject: Re: [PURRS-devel] base case assumptions Date: Mon, 29 Dec 2003 21:22:03 -0500 From: Shailesh Humbad <humbads@alum.mit.edu> To: Roberto Bagnara <bagnara@cs.unipr.it> References: <6.0.0.22.0.20031226022754.01ccf318@nyip.net> <3FEF09D2.2040706@cs.unipr.it> Thanks for confirming my suspicion and for making the research demo available online. It's a very useful tool for those of us who don't have access to Mathematica. By the way, when the base cases are defined and a correction term added to the formula given by PURRS, the solution to the recurrence reduces to [(n-2)*(n-1)]/2. Regards, Shailesh At 11:50 AM 12/28/2003, you wrote:

Shailesh Humbad wrote:

...

I am having a problem with the online version of PURRS. I tried it on a recurrence relation derived from an algorithm I'm working on, and the resulting formula is off by one for even n. I believe it may be something to do with our assumptions for the base cases and starting index. Is that something that would affect the results?

Dear Shailesh,

you are right: the online demo assumes that, for a recurrence of order k, the initial conditions are given for x(0), ..., x(k-1). We are working at a revision of our system (that currently is, remember, only a research prototype) that will allow to specify any set of initial conditions and special cases. We will also extend the online demo so as to make this facilities available through the web.

...

Thanks and Happy Holidays,

Thanks for your input. Have a great 2004,

Roberto Bagnara on behalf of the PURRS team

-- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it

-- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it