Gambit-list Avril 2013

gambit-list@iro.umontreal.ca

21 participants
51 discussions

FFI **Argv
by sales.creditscore＠creditscore.co.nz 16 Avr '13

16 Avr '13

Hi, I'm trying to call a C foreign function which uses command-line arguments... ; ;Isectd echo worker in Scheme ; (c-declare "#include \"isdio.h\"") (define isdLogInit (c-lambda (int (pointer (pointer char)#f)) void "isdLogInit")) (isdLogInit (-(length (command-line))1) (command-line)) The FFI C function isdLogInit function is: Xport void isdLogInit(int argc, char **argv) { int i; char isdLogFileName[1024]; sprintf(isdLogFileName, "/isect/logs/%s.log", argv[1]); isdLogFile = fopen(isdLogFileName, "a"); if (isdLogFile == NULL) isdLogFile = stderr; isdLog("\nSTARTING\n"); for (i = 0; i < argc; i++) isdLog("%s ", argv[i]); } It compiles OK, but when I run it, I get the message (Argument 2) Can't convert to C pointer. That's because (command-line) is a list of strings. Seems I can't cast to the required char **argv using Scheme. How do I capture the command-line as the correct type. Sorry, if this is straightforward. I'm not an academic or a professional programmer, just an electrician who likes to play with things to see how they work. If I can understand Scheme then I might eventually be able to contribute to GnuCash which I use in my business every day. Cheers, Rob.

2 1

null device on windows
by Ralph Moritz 15 Avr '13

15 Avr '13

On Unix the null device is /dev/null. On Windows NT+ the equivalent is NUL. We can verify this by writing the following small C++11 program: #include <cstdio> int main() { auto f = fopen("NUL", "r"); if (f == nullptr) { fprintf(stderr, "Cannot open file `NUL'."); return 0; } printf("Opened file `NUL' successfully."); } The above program, when compiled and run on Windows, will always print "Opened file `NUL' successfully." This brings me to Gambit, via Black Hole. BH contains some code (in compile-load.scm and lib.scm) that assumes `/dev/null' exists. This is obviously not true on Windows where instead we have `NUL'. It's easy enough to modify BH accordingly but the problem remains that Gambit tries to normalize all paths passed to `compile-file-to-target' so we end up with `<absolute path to cwd>\NUL' instead of just `NUL'. This essentially prevents us from using the null device as input to `compile-file-to-target' on Windows & means the following code from BH will fail on Windows: (define (compile-sexp-to-c sexp fn #!key (options '())) (##gc) ;; Avoid out-of-memory related crashes (let ((hook (lambda (_) sexp)) (prev-hook #f)) (dynamic-wind (lambda () (set! prev-hook c#expand-source) (set! c#expand-source hook)) (lambda () (compile-file-to-target "/dev/null" ;; Change to "NUL" on Windows output: fn options: options)) (lambda () (set! c#expand-source prev-hook))))) I've searched through the Gambit source code & tried to make the necessary changes to get this working but have been unable to do so. I probably just don't yet have a good enough understanding of the code. (I tried modifying ___os_path_normalize_directory in lib/os_files.c) Is anyone able to help with this? I really want to run Black Hole on Windows! Many thanks, Ralph

3 7

How to build with Visual C++ 11 (2012)
by Ralph Moritz 13 Avr '13

13 Avr '13

Hi, I've downloaded `gambc-v4_6_7-devel.tgz' and want to compile it with MSVC 11. I've tried tweaking `misc\vc2008.bat' but it bombs out with errors :-( How are the prebuilt VC binaries on the Gambit homepage built - ie. what's the recommended way to do this? Cheers, Ralph

4 8

Copying arrays C<->Scheme
by Álvaro Castro-Castilla 12 Avr '13

12 Avr '13

There is one thing that I've been meaning to ask for a long time now. I see most of the people tend to create arrays in C by malloc/___alloc_rc and then assigning values by iterating over them via a setter function (also defined with c-lambda). Isn't there a way to directly do this with a memcpy operation? Wouldn't that be faster? I understand that Gambit's heap and C's heap are separate, and you need to copy from one another in order to avoid GC touching any of FFI-created memory. But is it possible to improve this process using some sort of C function/macro from Gambit? I really can't find any code examples or reference for this. Thank you very much. Álvaro

2 3

malloc/free vs ___EXT(___alloc_rc)/___release_rc
by Álvaro Castro-Castilla 12 Avr '13

12 Avr '13

Hi, I'd like to know what's the main difference between using the malloc/free combination vs. the ___EXT(___alloc_rc) / ___EXT(___alloc_rc) one. Mi intention is to create C arrays and manage them from the Scheme side, so I can explicitly free them once I need to. Which one should I use? Thank you, Álvaro

2 2

Re: [gambit-list] code optimization & compilation
by Guillaume Lathoud 10 Avr '13

10 Avr '13

Hello, Thanks to both of you for the advice, I have obtained performance improvements using (declare .. (block) (not safe)) and removing the assignment to sum. My Gambit was configured with --enable-single-host only. I have to try to add--enable-gcc-opts Removing the assignment to the result vector would be a bit more work I guess, but incidentally that is what the "flat" code avoids: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul342.… ...which brings me to Marc's questions: "There are many things you can do to improve the performance of your code, but I wonder what you are trying to achieve. For instance, your code is multiplying matrices of small exact integers. Is this a given in your problem or you want the code to work also for floating point numbers? Also, do you want the code to conform to a specific standard of Scheme, or you are willing to adapt your code to a specific Scheme implementation? For Gambit you could store the numbers in a homogeneous numerical vector (e.g. s16vector, f64vector, etc) instead of a plain vector, and use fixnum specific operations for computing the indices of the matrix." I first wanted to check whether generating flat code would help to bring big performance improvements without too much specific work - basically looking for a sweet spot. So I wrote such "flat code" on this small example - manually translating from the generated JavaScript code, see the links below - and wrote to the mailing list hereto make sure that I am not missing something obvious while compiling, as well as in the baselines I have been comparing with (classic and list_of_lists). Now the real deal is to be able to express more complex mathematical expressions, and have "flat" code automaticallygenerated: http://glat.info/flatorize/#dft http://glat.info/flatorize/#push-dft1024 You can click on the "Try flatorize" buttons to see the generated JavaScript code. It was not straightforward to getthe code generation to work in a tractable time for significantly recursive cases such as the 1024-point DFT. Back to Marc's questions: my first goal is to remain generic and see how far one can go with the code generation - at this point of time I only wanted to eliminate big mistakes, thanks for the help. Now, in addition, since Gambit provides many interesting optimization possibilities, I certainly would like to try them as well. The challenge would be to provide means to specify where the generated code should use them (instead of writing or changing everything manually). Suggestions are welcome. Now, just speculating: could the Gambit compiler automatically detect and flatten such mathematical expressions? In such a case it would not be necessary to "pre-generate" flat code. On a side note a quick try in C showed a speedup as well: https://github.com/glathoud/flatorize/blob/master/explore/C/cAll_matmul.res… Best regards, Guillaume ________________________________ De : "gambit-list-request(a)iro.umontreal.ca" <gambit-list-request(a)iro.umontreal.ca> À : gambit-list(a)iro.umontreal.ca Envoyé le : Mardi 9 avril 2013 18h00 Objet : Gambit-list Digest, Vol 103, Issue 10 Today's Topics: 1. code optimization & compilation (Guillaume Lathoud) 2. Re: code optimization & compilation (Alex Queiroz) 3. Re: code optimization & compilation (Alex Queiroz) 4. Re: code optimization & compilation (Marc Feeley) ---------------------------------------------------------------------- Message: 1 Date: Tue, 9 Apr 2013 05:36:00 +0100 (BST) From: Guillaume Lathoud <glathoud(a)yahoo.fr> Subject: [gambit-list] code optimization & compilation To: Gambit List <gambit-list(a)iro.umontreal.ca> Message-ID: <1365482160.5341.YahooMailNeo(a)web171306.mail.ir2.yahoo.com> Content-Type: text/plain; charset="utf-8" Hello, on a simple task - multiply two matrices mat_a and mat_b https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_com… - I've been comparing 3 implementations, using interpretation and compilation. To compile I used the line below. Is there a better way, at least a few straightforward optimization (options) ? gsc -exe -o scheme_matmul_classic.bin tmp.scmDetails are below. Best regards, Guillaume 1. Functional implementation: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_lis… 2. Ugly imperative implementation: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_cla… 3. Flat implementation (for the specific matrix sizes): https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul342.… To run both tests (interpreted and compiled), I used this: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul.sh#… Results: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul.res…

1 0

code optimization & compilation
by Guillaume Lathoud 09 Avr '13

09 Avr '13

Hello, on a simple task - multiply two matrices mat_a and mat_b https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_com… - I've been comparing 3 implementations, using interpretation and compilation. To compile I used the line below. Is there a better way, at least a few straightforward optimization (options) ? gsc -exe -o scheme_matmul_classic.bin tmp.scmDetails are below. Best regards, Guillaume 1. Functional implementation: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_lis… 2. Ugly imperative implementation: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul_cla… 3. Flat implementation (for the specific matrix sizes): https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul342.… To run both tests (interpreted and compiled), I used this: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul.sh#… Results: https://github.com/glathoud/flatorize/blob/master/explore/scheme_matmul.res…

3 3

Mac OS X master doesn't seem to want to build for 64-bit
by Jason Felice 08 Avr '13

08 Avr '13

My installed version is 64-bit, but master seems to want to build 32-bit with just plain ./configure Any ideas? -Jason

1 0

Make a REPL load macros
by Jason Felice 07 Avr '13

07 Avr '13

Another question: I made a REPL with the following code: (include "../lib/objc#.scm") (include "~~lib/_gambit#.scm") (macro-readtable-bracket-keyword-set! ##main-readtable ':) (##repl-debug-main) Macros aren't available in the REPL (unless I included them from within the REPL). I understand what's going on, but not sure how to make it work. I'm hoping I can compile macros so I don't need to count on the objc#.scm file being around at run time, but if not - ah well. -Jason

1 0

Wiki accounts
by Jason Felice 07 Avr '13

07 Avr '13

I can't request one because there's some kind of invalid URL with the math problem captcha. I was going to try to update the source control page, which points to an out of date repository. On a separate note: The github repository does not have version tags. I'd like to get a cocoapod up and running for using gambit on iPhone, and it prefers using a git repository and a tag for downloading the source. I assume it could be a hash instead of a tag, and I'm busy figuring out which hash to use. Thanks, -Jason

1 0

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Gambit-list Avril 2013