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RE: [gambit-list] gambit 4 beta 12 on Win32
by Dan Hristodorescu 09 Fév '05

09 Fév '05

Hi Patrick, I had success with mingw (using msys shell) and I think it's a better option than cygwin since it doesn't depend on any other dlls. There are some tricks to make it work with the windows command prompt since after installation it assumes it's a unix environment and tries to execute a shell script. You'll have to create a batch file for that in order to compile with gsc. I could compile standalone exes, libraries to load in the interpreter including Meroon object system. I compile with gsc from the command prompt (the interpreter and compiler have some display problems with msys) and afterwards I use bash to compile the generated C files with gcc. After a lot of work (trying different ways to do it) I finally got a standalone exe with Meroon included and some test classes. If you need any help to set it up let me know. It does also work with Visual Studio 6 but you'll have to update the projects in the misc directory (they are old). I cannot comment on performance of the two different compilers, I only got some "line too long" errors in VS6 but it works. My choice was primarily based on the fact that mingw is open source and a lot of C libraries come with autoconf instead of VS projects. Regards, Dan Hristodorescu. -----Original Message----- I'd like to run beta 12 on Win32. Is there a technical reason a system has not been built yet? What would be the best way to build beta 12 for Win32? - Using an IDE config included in the distribution? - Using one of the Win32 shell scripts - Perhaps under Cygwin? I assume gcc is the preferable compiler, so perhaps the best choice is DJGPP and perhaps Cygwin second choice. Has anyone tried Cygwin? A google was inconclusive. Thanks, Patrick

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Gambit is great: the manual should advertise better
by Bill Richter 09 Fév '05

09 Fév '05

I'm a very satisfied Gambit user, as my program became fast enough to refute some C calculations my advisor made 20 years ago. My advisor was clever enough to prove his answers were wrong, even though his program no longer runs. Thanks to Marc for offering to help optimize my code: that got me to look at my code myself and make an obvious optimization. Guillaume's profiler certainly helped locate a hotspot. But I think Gambit is a lot better than the manual would indicate to a non-expert schemer like me. I have 4 "advertising" tips: ************ blinding speed ************ The first node does some great advertising: With appropriate declarations in the source code the executable programs generated by the compiler run roughly as fast as equivalent C programs. I believe this now, with my program's speed. But it would be even better if you cross-ref'ed the node "Miscellaneous extensions", where `declarations' is explained, and if that node included Guillaume's advice to me: stick something like this at the top of your program: (declare (standard-bindings) (fixnum) (not safe) (inline) (inlining-limit 1000) (block)) One thing great about "fast as equivalent C programs" is it's the first thing a reader will see! If you bury great stuff deep in the manual, then maybe you'll restrict your users to expert programmers. The manual looks very accurate to me, but it's very technical. ************ great debugger ************ I've often felt that bad or nonexistent debuggers is the Achilles heel of Scheme. But it looks to me like Gambit has a great debugger! I think the first node "The Gambit-C system" shoul say something like: `Gambit has a good debugger. See the examples in the nodes "Debugging commands" and "Procedures related to debugging" for examining variables in case of an error, and breakpoints and single-stepping.' ************ Case sensitive ************ The node "Runtime options for all programs" says that Gambit is case-sensitive by default. I think that's a huge plus, and should be mentioned in the 1st node. I think all mathematically-inclined folks will agree with me, as one typically writes, "Let X be a set, and let x be an element of X", which turns naturally into Scheme (let ([x (car X)]) ...) I think you should target folks who use DrScheme, written by your R6RS co-Editor Matthew Flatt. DrScheme is really slow, but it has some real pedagogical advantages, I think, including case-sensitivity. I would've used Gambit years ago if I'd known it was case-sensitive. ************ read-all: don't compile data ************ I finally understood some advice Guillaume posted: don't load/include big data files: it slows down gsc/gcc unbearably. You don't need to load/include, because of Gambit extensions like read-all. This helps with my Curtis-algorithm program, but it was crucial for an example program, where I gave an independent refutation of an error my advisor made in t = 71, where I differentiated a polynomial with 75,000+ terms of length 10! In 16.6 minutes! Look at this short program: (declare (standard-bindings) (fixnum) (not safe) (inline) (inlining-limit 1000) (block)) (include "adem.scm") (define inport (open-input-file "tag-data-t-71")) (define X (read-all inport)) (close-input-port inport) (pretty-print (length X)) (pretty-print (Poly-first X)) (time (pretty-print (Poly-first (D X)))) 75299 (4 8 4 5 3 5 9 3 5 7 7) (3 4 4 2 3 5 3 5 9 7 7 7) (time (pretty-print (Poly-first (D X)))) 998093 ms real time, 16.6 minutes 997940 ms cpu time (997840 user, 100 system) 3204 collections accounting for 365525 ms real time (365690 user, 30 system) 112648202368 bytes allocated 13318 minor faults 3 major faults BTW can someone explain this figure, 112648202368 bytes allocated? Did I really use 112.6 gB? My machine "only" has 1 gB of memory. An important extension to Scheme like `read-all' maybe should be more prominently mentioned, and it's usefulness stressed. The description is fine, but I didn't find these examples very illuminating: - procedure: read-all [PORT [READER]] This procedure repeatedly calls the procedure READER with PORT as the sole argument and accumulates a list of each value returned up to the end-of-file object. The procedure `read-all' returns the accumulated list without the end-of-file object. If it is not specified, PORT defaults to the current input-port. If it is not specified, READER defaults to the procedure `read'. For example: > (call-with-input-string "3,2,1\ngo!" read-all) (3 ,2 ,1 go!) > (call-with-input-string "3,2,1\ngo!" (lambda (p) (read-all p read-char))) (#\3 #\, #\2 #\, #\1 #\newline #\g #\o #\!) > (call-with-input-string "3,2,1\ngo!" (lambda (p) (read-all p read-line))) ("3,2,1" "go!")

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[gambit-list] subvector, vector-copy, vector-append need to be documented
by Bradley Lucier 09 Fév '05

09 Fév '05

Marc: You need to document the following nonstandard procedures (found by Maxim Naumov) in the Gambit documentation: vector-copy subvector vector-append These are documented for all the homogenous vector types but not for heterogeneous vectors. Brad

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New types
by Eduardo Cavazos 09 Fév '05

09 Fév '05

Is there a way to create new primitive types in Gambit? I'm using 3.0 but I'm interested in answers regarding either version. My simple object system builds 'objects' out of procedures with local state. E.g.: (let ((x 10) (y 20)) (lambda args ...)) The (classic?) problem here is that my 'objects' don't look different from procedures. If I know that I'm dealing with one of my objects, I can ask it what it it is. But if I'm dealing with something that can be any Scheme type, I can ask if it's a procedure, but then I can't tell if it's one of my objects or a proc... I need a way to have a 'new' procedure type. A type of primitive item that acts just like a procedure but answers #f to the 'procedure?' predicate. I guess I am abusing procedures with this style of object system. But I'm hacking so it's OK. ;-) Ed

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gambit 4 beta 12 on Win32
by Logan, Patrick D 08 Fév '05

08 Fév '05

I'd like to run beta 12 on Win32. Is there a technical reason a system has not been built yet? What would be the best way to build beta 12 for Win32? - Using an IDE config included in the distribution? - Using one of the Win32 shell scripts - Perhaps under Cygwin? I assume gcc is the preferable compiler, so perhaps the best choice is DJGPP and perhaps Cygwin second choice. Has anyone tried Cygwin? A google was inconclusive. Thanks, Patrick

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We need to update the SRFI license
by david rush 02 Fév '05

02 Fév '05

Hi Marc, As you may have heard, we are changing in the SRFI license to accomodate the currently expressed needs of the Open Source community for a legally evaluated license. To this end we are shifting to the MIT license. David VanHorn has been heading up this effort; you may have heard from him already. We need you to send an email back to the srfi-editors(a)srfi.schemers.org explicitly giving your permission to re-license SRFIs 0, 4, 12, 18, 21, 39. We *don't* have a good plan for handling SRFIs which we are unable to secure the necessary re-licensing permissions, and we would *vastly* prefer to have your approval to having to concoct such a plan. We have had interesting ... suggestions ... from both the Scheme Underground and the NJDSS Editorial team in their own unique modalities about how to handle the situation. Let us pray it doesn't come to that. david rush -- Remember: There is no Scheme Underground

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What are the default compiler declarations?
by Bradley Lucier 02 Fév '05

02 Fév '05

Marc: The documentation says: The default declarations used by the compiler are equivalent to: (declare (ieee-scheme) (separate) (inline) (inlining-limit 300) (constant-fold) (lambda-lift) (not standard-bindings) (not extended-bindings) (not run-time-bindings) (safe) (interrupts-enabled) (generic) (mostly-fixnum) ) but it appears that standard-bindings is also assumed, by the following test. I think this is a bug. Brad [descartes:~] lucier% gsc -c -expansion test.scm loading /usr/local/Gambit-C/gambcext.scm Expansion: (define a (lambda (b) (if (##pair? b) (##car b) (car b)))) [descartes:~] lucier% cat test.scm (define (a b) (car b)) [descartes:~] lucier% cat test.c <stuff deleted> #undef ___PH_PROC #define ___PH_PROC ___H_a #undef ___PH_LBL0 #define ___PH_LBL0 3 #undef ___PD_ALL #define ___PD_ALL ___D_FP ___D_R0 ___D_R1 ___D_R4 #undef ___PR_ALL #define ___PR_ALL ___R_FP ___R_R0 ___R_R1 ___R_R4 #undef ___PW_ALL #define ___PW_ALL ___W_R1 ___W_R4 ___BEGIN_P_COD ___BEGIN_P_HLBL ___DEF_P_HLBL_INTRO ___DEF_P_HLBL(___L0_a) ___DEF_P_HLBL(___L1_a) ___END_P_HLBL ___BEGIN_P_SW ___DEF_SLBL(0,___L0_a) ___IF_NARGS_EQ(1,___NOTHING) ___WRONG_NARGS(0,1,0,0) ___DEF_GLBL(___L_a) ___IF(___PAIRP(___R1)) ___GOTO(___L2_a) ___END_IF ___POLL(1) ___DEF_SLBL(1,___L1_a) ___JUMPGLOSAFE(___SET_NARGS(1),2,___G_car) ___DEF_GLBL(___L2_a) ___SET_R1(___CAR(___R1)) ___JUMPPRM(___NOTHING,___R0) ___END_P_SW ___END_P_COD

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[gambit-list] Re: Scheme/C help request for code needed for Math paper
by Bill Richter 31 Jan '05

31 Jan '05

Marc, with a new sorting algorithm, I'm going so much faster, I can't even quantify it! I've updated my web page code: http://www.math.northwestern.edu/~richter/Richter-Curtis-algorithm.tar.gz I would like to go even faster, as I'm hitting the wall at t = 71. Look at ps -aux: richter 7052 65.9 91.2 1110356 927876 pts/0 D 21:49 16:56 ./71-72zariski.out I'm using 91.2% of the 1 GB memory, which is great, but only 65.9% of the cpu, which means I'm paging out to disk, I think. So unless you Scheme wizards have another trick for me, I'll have to quit at t = 70. I think there's a real lesson (which will take me 3 steps to get to) here about Math, C & Scheme, which you taught me by writing: I'm willing to give you some help on optimizing your code, but you should first try Guillaume Germain's profiler to understand where the time is spent ... 1) A fast smart Scheme->C translator is great for human programmers, because C code tends not to be human-readable, with all the allocation/de-allocation of pointers, just to say the worst of C. 2) But there's still Scheme optimizations to make, which might be hard on human-readability, and also general weird algorithm-hacks, such as the numerical methods which you & Brad are experts at, and I want to stay away from. I remember that Brad posted on cls that the gmp folks were real experts on numerical methods. gmp is just multiplying (large) numbers! I'm really glad the gmp folks (and Brad) are good at numerical methods, but I want to stay away from it myself. 3) But as you taught me by telling me to profile, there's also the "real" mathematical algorithm that we're using!!! By profiling, an ordinary non-wizard schemer like me might easily see that the algorithm needs changing at a "high level", i.e. not wizard-hacks. Something more specific about my code: I have more or less long lists of words, sorted alphabetically (i.e. in the left-lexicographical order), into which I want to merge individual new words. Let's say I have a list of words from "aardvark" to "zzzlurp", and I want to insert the word "mouse". I was just going through the list in order, comparing "mouse" against every word, till I got to a hole between say "Morse" & "move" to insert "mouse". To me, that looked OK, but Guillaume's profiler showed I was spending about 50% of the time checking which of two English or French words was higher in the alphabetical order. Finally it dawned on me that there was a simple sorting fix I could make: store my "words" as trees. I didn't realize this because I'm a sorting expert (I'm anything but!), but because I realized that's how we look up words in the dictionary, which has little black letters engraved so we can go right to the "M" chapter to find "mouse". Why not keep going, have trees, instead of just clumping by the 1st letter? Back to Gambit Scheme->C speed, these numbers are fast to me: ;; t = 0->55, 2.4 minutes ;; t = 56->60, 11.2 minutes ;; t = 61->65, 49.4 minutes, incl 31.0 minutes of garbage collection ;; t = 65->70, 74.3 minutes, incl 47.0 minutes of garbage collection With my new sorting algorithm, I'm even getting acceptable speed on DrScheme: ;; t = 0->55, 10.0 minutes ;; t = 56->60, 43.5 minutes When I wrote this code a few years ago, I couldn't get up to t = 60 running DrScheme job (actually byte-compiled mzc) all night. I just profiled t = 59, and it took 35.4 minutes, showing the speed of the Gambit C code, and the power of Guillaume's speed-hack: (declare (standard-bindings) (fixnum) (not safe) (inline) (inlining-limit 1000) (block)) t = 59 is important to me, because that's the 1st place where my output diverges from my advisor's. I'm sure I'm right, partly because DrScheme replicated my answer. I only found 4 divergences for t <= 70 between my output and his 20 yr old Stone-age Sun2 C output. The hotspots are 2 functions in Lambda-defs.scm. I spent 29% of the time in Poly->Tree, which converts my polynomials (my list of English/French words) into trees, and 36% of the time in merge-trees, which merges 2 trees, both in Lambda-defs.scm. That's still a lot, but it's a big an improvement over my old sorting code, when I spent 63% of the time in Mono-left-lex, and 29% in merge-1. I got my percentages by my usual Emacs kbd macro kludge: (+ 588 240 2081 2527 6764 540 590 3044 160 3133 456 2388 3542 2386 4865 378 417 2717 2468 287 3551 ) 43122 (/ 43122.0 148005) 0.2913550217898044 (+ 5761 2007 666 1338 188 21539 662 800 814 743 762 5872 51 805 1238 438 1069 2794 620 1501 3126) 52794 (/ 52794.0 148005) 0.3567041653998176 The profile html dir is included in my new tar.gz file. -- Best, Bill

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Re: gambit.el
by Marc Feeley 27 Jan '05

27 Jan '05

> Hi Marc, > > FYI > > The file gambit.el in the latest (4b12) distribution has a comment > line near the start > > ;; (setq scheme-program-name "gsi -:t") > > After pasting this line in my xemacs init.el the interaction window > didn't work. Changing it to > > ;; (setq scheme-program-name "gsi -:d-") > > as described in the doc fixed it. > > Since others, like me, will be tempted to cut and paste from the > gambit.el file comments to init.el it would be nice to fix the > comment. > > Regards, OK. Marc

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Scheme/C help request for code needed for Math paper
by Bill Richter 27 Jan '05

27 Jan '05

I have almost 800 lines of Gambit code, at the top of my web page http://www.math.northwestern.edu/~richter/Richter-Curtis-algorithm.tar.gz and I hope someone can help me make the code run faster. My advisor got roughly similar speed 20 years ago on stone-age Sun2s, but writing C code directly. Seems to me that a Scheme->C translator like Gambit (Version 4.0 beta 11) ought to perform comparably to writing the program in C. At least if the Scheme code is good! I can see two possible ways to improve the Scheme code: 1) slicker datatypes for some lists of lists of small integers 2) more sophisticated sorting but I have no idea. I worked pretty hard to clean the code up, to make it readable, but I'm no speed wizard, like you and Brad. My code computes some list for each nonnegative t, and it starts to bog down at t = 50. Here's the time output for t = 53: 7044096 ms real time 6974840 ms cpu time (6953810 user, 21030 system) 43801 collections accounting for 1622147 ms real time (1602770 user, 2510 system) 524299620112 bytes allocated 3641413 minor faults 10 major faults That's 117.4 minutes of real time, almost 2 hours, including 27.0 minutes of garbage collection, and it looks to me like 524 gB of RAM (can that be right? the machine has 1 gB RAM and a 2.4 GHz cpu). But 2 hours in about as long as I can sit down at the console of a public machine, and if I submit a job and log out, it hangs. It hangs also if I nice a job. These 2 facts seem very strange to me. So I've gotten as much output as I'm going to get, unless you can help me out, or I win the lottery and buy a machine like this for myself. Here's something funny about nice/log-out: The job for t = 52 ran (un-niced) in 82 minutes, while I was sitting at the console of this public machine. But when I ran it nice-ed, it didn't finish in 7 hours, even with 3 of those hours sitting at the console. -- Best, Bill

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