Path: utzoo!attcan!uunet!mcsun!ukc!edcastle!aipna!cstr!tim From: tim@cstr.ed.ac.uk (Tim Bradshaw) Newsgroups: comp.lang.lisp Subject: Re: REAL LISP applications Message-ID: Date: 30 May 90 09:59:39 GMT References: <1990May24.195449.15510@king.mcs.drexel.edu> <1990May25.221509.21274@evax.arl.utexas.edu> <22308@dartvax.Dartmouth.EDU> <45898@iuvax.cs.indiana.edu> Sender: news@aipna.ed.ac.uk Organization: CSTR, University of Edinburgh Lines: 32 In-reply-to: raja@silver.ucs.indiana.edu's message of 28 May 90 00:53:46 GMT In article <45898@iuvax.cs.indiana.edu> raja@silver.ucs.indiana.edu (Raja Sooriamurthi) writes: > and of course MACSYMA. Considered by many to be an acid test > for any lisp system. I don't know of any of the other symbolic math > packages (Maple, Reduce etc., Mathematica is in C), but I suspect some of > them may be in Lisp. Reduce at least is in Lisp, the version I used to use was written in Standard Lisp, and the Standard Lisp was built on top of Cambridge Lisp. If you count algebra systems as `real lisp' applications then there are a suite of systems derived from LAM (Lisp Algebraic Manipulation): Sheep (a grown up LAM...) is a system for doing algebraic manipulation in General relativity; Classi is a program built on Sheep which classifies space-times in GR, and STensor is a general Symbolic Tensor manipulation program built on Sheep. Sheep and Classi at least make many interesting calculations in GR possible. The first application of LAM (in the late 60s I think) was to calculate the curvature of the Bondi space-time. This had previously been done by hand by someone, and the calculation had taken I think 3 months. LAM did it in 7 minutes (I think?) on an Atlas, and it was discovered that the hand calculation contained errors! It's a while since I did any of this, so details are likely to be wrong. --tim Tim Bradshaw. Internet: tim%ed.cstr@nsfnet-relay.ac.uk UUCP: ...!uunet!mcvax!ukc!cstr!tim JANET: tim@uk.ac.ed.cstr "Quis custodiet ipsos custodes?"