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Patch to roughly double the speed of generating pseudo-random inexact numbers.
by Bradley Lucier 16 Jan '09

16 Jan '09

A student was trying to use Gambit for a Monte-Carlo simulation, so I looked at the speed of generating inexact pseudo-random numbers. This patch adds a procedure (random-source-make-f64vectors rs #!optional (p (macro-absent-obj)) that returns an f64vector of pseudo-random inexact numbers. The purpose of this procedure is to avoid the trampoline in the very common case when inexact reals are needed in groups by an algorithm. It also adds the predefined procedure random-f64vector. There is some amount of duplication in the internal procedure (make-f64vectors precision) in order to have an allocation-free path for the generation of the random reals, so that the only memory allocated is for the f64vector itself. In one place I changed - (fl/ (fl+ (macro-inexact-+1) (f64vector-ref state 6)) - (macro-m1-plus-1-inexact))))) + (fl* (fl+ (macro-inexact-+1) (f64vector-ref state 6)) + (macro-inv-m1-plus-1-inexact))))) because the division wasn't necessary to preserve the correctness of the algorithm. (The divisions are necessary in advance-state! to preserve the correctness of the algorithm.) I changed advance-state! to avoid the final flfloor (it seems that flfloor, flonum->fixnum, ..., take a relatively long time on my Core 2 Duo compared to the usual addition, multiplication, ...); the new code still avoids boxing flonums. I also made state a local variable because the register allocator kept reloading it into registers, stack slots, etc., from the closure. And then I tried to document this stuff. I noticed that the optional precision parameter wasn't documented; was that intentional? Brad Tests: With test-random-reals.scm given by (declare (standard-bindings)(extended-bindings)(block)(not safe)) (define (make-random-f64vector n) (let ((result (make-f64vector n))) (do ((i (fx- n 1) (fx- i 1))) ((fx< i 0) result) (f64vector-set! result i (random-real))))) I get with current head frying-pan:~/programs/gambc-v4_4_0-devel> gsi Gambit v4.4.0 > (load "test-random-reals") "/home/lucier/programs/gambc-v4_4_0-devel/test-random-reals.o13" > (define a (time (make-f64vector 1000000))) (time (make-f64vector 1000000)) 7 ms real time 4 ms cpu time (0 user, 4 system) 1 collection accounting for 1 ms real time (0 user, 0 system) 8000048 bytes allocated 1984 minor faults no major faults > (define a (time (make-random-f64vector 1000000))) (time (make-random-f64vector 1000000)) 162 ms real time 160 ms cpu time (144 user, 16 system) 2 collections accounting for 1 ms real time (0 user, 0 system) 40000048 bytes allocated 4981 minor faults no major faults and with the changes I get frying-pan:~/programs/gambc-v4_4_0-devel> gsi/gsi Gambit v4.4.0 > (load "test-random-reals") "/home/lucier/programs/gambc-v4_4_0-devel/test-random-reals.o13" > (define a (time (make-f64vector 1000000))) (time (make-f64vector 1000000)) 6 ms real time 4 ms cpu time (0 user, 4 system) 1 collection accounting for 0 ms real time (0 user, 0 system) 8000048 bytes allocated 1982 minor faults no major faults > (define a (time (make-random-f64vector 1000000))) (time (make-random-f64vector 1000000)) 132 ms real time 132 ms cpu time (120 user, 12 system) 2 collections accounting for 1 ms real time (0 user, 0 system) 40000048 bytes allocated 4981 minor faults no major faults > (define a (time (random-f64vector 1000000))) (time (random-f64vector 1000000)) 73 ms real time 72 ms cpu time (64 user, 8 system) no collections 8000048 bytes allocated 1954 minor faults no major faults

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IFL 2009: Call for Papers
by Matthew Flatt 16 Jan '09

16 Jan '09

Call for Papers IFL 2009 Seton Hall University SOUTH ORANGE, NJ, USA http://tltc.shu.edu/blogs/projects/IFL2009/ The 21st IFL symposium, IFL 2009, will be held for the first time in the USA. The hosting institution is Seton Hall University in South Orange, NJ, USA and the symposium dates are September 23-25, 2009. It is our goal to make IFL a regular event held in the USA. The goal of the IFL symposia is to bring together researchers actively engaged in the implementation and application of functional and function-based programming languages. IFL 2009 will be a venue for researchers to present and discuss new ideas and concepts, work in progress, and publication-ripe results related to the implementation and application of functional languages and function-based programming. Following the IFL tradition, IFL 2009 will use a post-symposium review process to produce a formal proceedings which we expect to be published by Springer in the Lecture Notes in Computer Science series. All participants in IFL 2009 are invited to submit either a draft paper or and extended abstract describing work to be presented at the symposium. These submissions will be screened by the program committee chair to make sure they are within the scope of IFL and will appear in the draft proceedings distributed at the symposium. Submissions appearing in the draft proceedings are not peer-reviewed publications. After the symposium, authors will be given the opportunity to incorporate the feedback from discussions at the symposium and will be invited to submit a revised full arcticle for the formal review process. These revised submissions will be reviewed by the program committee using prevailing academic standards to select the best articles that will appear in the formal proceedings. TOPICS IFL welcomes submissions describing practical and theoretical as well as submissions describing applications and tools. If you are not sure if your work is appropriate for IFL 2009, please contact the PC chair at ifl2009(a)shu.edu. Topics of interest include, but are not limited to: language concepts type checking contracts compilation techniques staged compilation runtime function specialization runtime code generation partial evaluation (abstract) interpretation generic programming techniques automatic program generation array processing concurrent/parallel programming concurrent/parallel program execution functional programming and embedded systems functional programming and web applications functional programming and security novel memory management techniques runtime profiling and performance measurements debugging and tracing virtual/abstract machine architectures validation and verification of functional programs tools and programming techniques PAPER SUBMISSIONS Prospective authors are encouraged to submit papers or extended abstracts to be published in the draft proceedings and to present them at the symposium. All contributions must be written in English, conform to the Springer-Verlag LNCS series format and not exceed 16 pages. The draft proceedings will appear as a technical report of the Department of Mathematics and Computer Science of Seton Hall University. IMPORTANT DATES Registration deadline August 15, 2009 Presentation submission deadline August 15, 2009 IFL 2009 Symposium September 23-25, 2009 Submission for review process deadline November 1, 2009 Notification Accept/Reject December 22, 2009 Camera ready version January 15, 2010 PROGRAM COMMITTEE Peter Achten University of Nijmegen, The Netherlands Jost Berthold Philipps-Universität Marburg, Germany Andrew Butterfield University of Dublin, Ireland Robby Findler Northwestern University, USA Kathleen Fisher AT&T Research, USA Cormac Flanagan University of California at Santa Cruz, USA Matthew Flatt University of Utah, USA Matthew Fluet Toyota Technological Institute at Chicago, USA Daniel Friedman Indiana University, USA Andy Gill University of Kansas, USA Clemens Grelck University of Amsterdam/Hertfordshire, The Netherlands/UK Jurriaan Hage Utrecht University, The Netherlands Ralf Hinze Oxford University, UK Paul Hudak Yale University, USA John Hughes Chalmers University of Technology, Sweden Patricia Johann University of Strathclyde, UK Yukiyoshi Kameyama University of Tsukuba, Japan Marco T. Morazán (Chair) Seton Hall University, USA Rex Page University of Oklahoma, USA Fernando Rubio Universidad Complutense de Madrid, Spain Sven-Bodo Scholz University of Hertfordshire, UK Manuel Serrano INRIA Sophia-Antipolis, France Chung-chieh Shan Rutgers University, USA David Walker Princeton University, USA Viktória Zsók Eötvös Loránd University, Hungary PETER LANDIN PRIZE The Peter Landin Prize is awarded to the best paper presented at the symposium every year. The honored article is selected by the program committee based on the submissions received for the formal review process. The prize carries a cash award equivalent to 150 euros.

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Scheme in the service of evil---Interview with an Adware Author
by Bradley Lucier 14 Jan '09

14 Jan '09

The largest Scheme deployment ever, over 4 million machines ... Brad http://philosecurity.org/2009/01/12/interview-with-an-adware-author

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A Tour of Scheme in Gambit
by Mikael More 11 Jan '09

11 Jan '09

Published A Tour of Scheme in Gambit, that introduces people with experiences in general programming languages to Scheme in general and Gambit in particular. Uploaded under the Tutorials section of http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Documentation . Feedback is welcome. Mikael

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Wiki site migration
by Marc Feeley 09 Jan '09

09 Jan '09

I'm in the process of migrating the wiki to a faster machine. The files have been transferred and all seems to work, but I would like to get your feedback before making the change final. You can play with the new wiki here: http://dynamo2.iro.umontreal.ca Don't bookmark that page as the machine will soon be renamed to "dynamo" (so that all incoming hyperlinks will still be valid). Marc

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[ANN] Gambit-C v4.4.0 released
by gambit＠iro.umontreal.ca 24 Déc '08

24 Déc '08

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PICBIT, PICOBIT, etc.
by Andrew Lentvorski 18 Déc '08

18 Déc '08

A while back, there was mumbling about releasing these. Did this ever come to fruition? A small Scheme might be a nice brainteaser to mull over during Christmas break. Thanks, -a

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cross-compilation for dummies
by Oisín Mac Fhearaí 15 Déc '08

15 Déc '08

Hi all, I'm fairly out of my depth here, trying to compile Gambit such that it will cross-compile (on OS X) and produce executables that will run on my old m68k-based Palm (err, actually ARM-based, but with some weird caveats that make it easier to use 68k). There doesn't seem to be any documentation on how to do such a thing, but grepping in the latest source release implies that it can be done via the "--host" configure option. With the following configure command: ./configure --prefix=/Users/oisin/code/palm/scheme/gambit/ --host=m68k-palmos --enable-ansi-c --enable-char-size=2 --enable-single-host (the enable-ansi-c and char-size=2 options were just a stab in the dark and neither help nor hinder) and the following make line (for wchar.h): C_INCLUDE_PATH=/Users/oisin/.wine/drive_c/PalmOSCygwin/usr/include/ make ...I get hundreds of thousands of errors like this, before the build gives up: /var/folders/ra/raN9YbS9GOKB9pULa-Z47E+++TI/-Tmp-/cc7yLvmh.s:193444: Error: Value of 716162 too large for field of 2 bytes at 0x81dfa /var/folders/ra/raN9YbS9GOKB9pULa-Z47E+++TI/-Tmp-/cc7yLvmh.s:193444: Error: Signed .word overflow; switch may be too large; 716162 at 0x81dfa ..... make[1]: *** [_io.o] Error 1 make: *** [all-recursive] Error 1 Maybe this is because the 68k only has a 16-bit word size. Does it mean that Gambit C can't be build to compile for the 68k, or is there a way to do it? thanks, Oisín

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Re: [gambit-list] cross-compilation for dummies
by Oisín Mac Fhearaí 14 Déc '08

14 Déc '08

Hey all, > Error: Value of 716162 too large for field of 2 bytes at 0x81dfa Actually on further inspection, it looks like the Palm architecture limits code segments to 64k max, and clearly the code Gambit C will produce is going to be unavoidably bigger. There's presumably some way of breaking it into multiple segments, but it seems like a right headache so I'll leave it for now. Sorry for the noise! Oisín

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Matrix and linear algebra
by David St-Hilaire 12 Déc '08

12 Déc '08

Hi all! I currently need some basic linear algebra manipulation. I could easily write it myself, but I'm sure that someone else has, already! hehe Has anyone such a library available (open source)? If so, is it possible to have it on the dumping grounds? Many Thanks!! David

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