December 2007 - MSLUG - mailman.iro.umontreal.ca

cons, car, cdr?
by Derek Mahar 19 Dec '07

19 Dec '07

Not long ago I started to read Teach Yourself Scheme in Fixnum Days (http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-1.html) Section 2.2.3 Dotted Pairs and Lists (http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-1.html#node_toc…) introduces the functions cons, car, and cdr. Are these function names abbreviations or acronyms? What words do they represent? More specifically, what does the 'a' in car mean and what does the 'd' in cdr mean? Thank you, Derek

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Significance of 'C' in "Gambit-C"
by Derek Mahar 10 Dec '07

10 Dec '07

Out of curiosity, what is the significance, if any, of the 'C' in "Gambit-C"? Was there a "Gambit-A" and "Gambit-B"? Was it implemented in C? Derek

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Floating point speed of Gambit-C
by Marc Feeley 10 Dec '07

10 Dec '07

Yesterday at the MSLUG meeting Houman Zolfaghari gave an interesting talk on the use of Scheme in the "real-world". In his presentation he said that in his work he uses both C++ and Scheme; the parts that do floating-point intensive computations are programmed in C++ and the scripts are written in Scheme. An audience member asked why Scheme was not being used for the numerical computations. Houman stated, as if it was common knowledge, that C++ had better performance than Scheme on numerical computations. I have heard this misconception from several people, and I am compelled to set the record straight, at least to the MSLUG members who should know better. Brad Lucier has been using Gambit-C for floating-point intensive computations for a long time. His involvement with Gambit-C has helped me improve the compiler's performance on numerical computation. For the kind of computations that he does (partial differential equations) the performance of Gambit-C is equal to that of C. The short paper he wrote on the subject, presented at the 2000 Scheme workshop, is: http://www.ccs.neu.edu/home/matthias/Scheme2000/lucier.ps Of course the performance compared to C++ might be different for different numerical computations. The important message here is that the performance of floating point code can be in the same ballpark as C ++. If some computational kernels are critical to overall performance, it might even be possible to beat C++ by doing some agressive loop unrolling and function inlining of the kernel (which Gambit-C does automatically based on programmer declarations). Marc

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MSLUG Meeting December 5th 2007 7pm -- Commercial Users of Scheme and Lisp
by Guillaume Germain 08 Dec '07

08 Dec '07

Greetings, this is the official announce for the next meeting of the MSLUG. What: Montreal Scheme/Lisp User Group Meeting Where: Room 3195, André-Aisenstadt Building, Université de Montréal, 2920 chemin de la Tour (you can find a plan of the UdeM campus here: http://www.stcum.qc.ca/metro/images/c56.pdf) When: December 5th 2007 at 7pm We will have the chance to hear 4 different talks, of around 15 to 20 minutes each, about using Scheme and Lisp in a commercial setting. After the talks, those of us who feel so inclined will go down to a nearby pub to have a beer and continue the discussion. The meeting is open to everyone, feel free to invite friends and co-workers! See you next Wednesday, Guillaume * Talks Program * 1- Houman Zolfaghari : Using scheme in the industry: a possibly powerful but difficult choice Having used scheme/lisp for more than 12 years in the industry for some large scale projects, I will talk a bout my experience and my latest considerations and conclusions. ---------- 2- Dominique Boucher : Scheme in the enterprise: pitfalls to avoid In this short presentation, I will share my experience introducing Scheme in an industrial setting. I will mainly focus on how to avoid some common pitfalls. ---------- 3- Daniel Villeneuve & Alain Marcotte : Three goals, 2 companies, 1 ... Overview of 3 utilizations of scheme in two different companies where scheme is part of delivered products. A glance at the architecture and environment for those products. Survol de 3 utilisations de scheme à travers 2 entreprises: Micro-Intel (Cogniscience) et ADOPT (Kronos). Survol de l'environnement et architecture où scheme fait partie des produits livrés. ---------- 4- Guillaume Cartier : Overview of the Chyma Scheduler, a rule-based scheduler for hospitals written for IsaiX Technologies using JazzScheme under its new open source license. I will also discuss how it has been possible for us on various occasions to help clients with Lisp based solutions when the hurt was considerable and Lisp was seen as the only doctor with potent enough medicine.

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Meeting Tonight
by Yan Laporte 05 Dec '07

05 Dec '07

Je ne pourrais malheureusement pas m'y rendre mais le sujet m'intéresse beaucoup, est-ce que quelqu'un pensait filmer le présentations? Unfortunately I won't be able to make it. Was anyone planning to film the sessions? yl

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Reminder: MSLUG Meeting tonight --Commercial Users of Scheme and Lisp
by Guillaume Germain 05 Dec '07

05 Dec '07

Hi everybody, just a reminder that the MSLUG meeting is tonight, Wednesday December 5th at 7pm. All the information about the meeting can be found here: https://webmail.iro.umontreal.ca/pipermail/mslug/2007-November/000236.html See you there! Guillaume

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