December 2019 - Gambit-list - mailman.iro.umontreal.ca

Gambit versus Python+GMP: Timing for Chudnovskys' algorithm for pi
by Bradley Lucier 07 Apr '22

07 Apr '22

Bakul Shah wrote a particularly elegant Scheme program for Chudnovskys' algorithm for pi based on the Common Lisp program here: https://bitbucket.org/tarballs_are_good/numericl/src/5fe8fe7089f48ab1c8a388… Nick Craig-Wood wrote a Python program using the GMP multiprecision library that appears to use exactly the same algorithm here: http://www.craig-wood.com/nick/articles/pi-chudnovsky/ I modified both programs a bit and include them here. They time the calculation of $10^n$ digits of pi for $n=1,2,3,4,5,6,7$. The results are heine:~/programs/gambiteer/gambit> !py python pi_chudnovsky_bs_gmpy.py 31415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679 ('chudnovsky_gmpy_mpz_bs: digits', 10, 'time', 1.0967254638671875e-05) ('chudnovsky_gmpy_mpz_bs: digits', 100, 'time', 3.0040740966796875e-05) Last 5 digits 70679 OK ('chudnovsky_gmpy_mpz_bs: digits', 1000, 'time', 0.00025582313537597656) Last 5 digits 01989 OK ('chudnovsky_gmpy_mpz_bs: digits', 10000, 'time', 0.00386810302734375) Last 5 digits 75678 OK ('chudnovsky_gmpy_mpz_bs: digits', 100000, 'time', 0.0834801197052002) Last 5 digits 24646 OK ('chudnovsky_gmpy_mpz_bs: digits', 1000000, 'time', 1.655979871749878) Last 5 digits 58151 OK ('chudnovsky_gmpy_mpz_bs: digits', 10000000, 'time', 30.67442488670349) Last 5 digits 55897 OK heine:~/programs/gambiteer/gambit> gsi chud1.scm Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 10, CPU time: 0.. Last 5 digits 26535. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 100, CPU time: 0.. Last 5 digits 70679. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 1000, CPU time: .004. Last 5 digits 1989. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 10000, CPU time: .028. Last 5 digits 75678. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 100000, CPU time: .472. Last 5 digits 24646. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 1000000, CPU time: 6.448. Last 5 digits 58151. Chudnovsky's algorithm using binary splitting in Gambit Scheme: digits 10000000, CPU time: 98.612. Last 5 digits 55897. So it appears that for this algorithm applied to large integers, GMP's bignum routines are about 3-4 times as fast as Gambit's bignum routines. Not so bad. For smaller bignums, GMP has a bigger advantage. The C program gmp-chudnovsky.c includes certain optimizations to this basic algorithm: http://gmplib.org/pi-with-gmp.html ftp://ftp.gmplib.org/pub/misc/gmp-chudnovsky.c On my machine, compiled with gcc -O3 -march=native -o gmp-chudnovsky gmp-chudnovsky.c -lgmp -lm the CPU times for 1,000,000 and 10,000,000 digits are 1.064 and 18.200 seconds, respectively. This is with a somewhat older machine model name : Intel(R) Core(TM)2 Quad CPU Q8200 @ 2.33GHz running Ubuntu 13.04 with heine:~/programs/gambiteer/gambit> gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.7.3-1ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs --enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.7 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --enable-objc-gc --with-cloog --enable-cloog-backend=ppl --disable-cloog-version-check --disable-ppl-version-check --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) heine:~/programs/gambiteer/gambit> gsi -v v4.6.9 20130607151908 x86_64-unknown-linux-gnu "./configure '--enable-single-host' '--enable-multiple-versions' '--enable-shared'" and the Ubuntu-provided GMP 5.0.5. (I'm sure the GMP folks have a better way to build GMP on my machine than the "generic" 64-bit version provided by Ubuntu.) Brad

7 18

authentication to update wiki?
by Iain Duncan 30 Dec '19

30 Dec '19

Hi Marc and team, I noticed on the wiki there was a request to update it with some more FFI practise examples. I would be happy to do so as I figure things out, if someone can tell me how to get a wiki editing account. thanks iain

1 0

Further examples of embedding gambit in C?
by Iain Duncan 30 Dec '19

30 Dec '19

Hi list, I'm new to Gambit, having been introduced to it by Marc from another list. (Thanks Marc!). My use case is that I want to embed a scheme interpreter in C code that is run under the SDK in Max/MSP, to do algorithmic composition and interactive computer music, making a scheme interpreter object for Max/MSP that receives scheme code from the user and calls underlying C SDK functions in Max. I'm currently working on it using S7 scheme and also evaluating other schemes as potential better long term solutions. Marc sent me the example code from the "embedding" tarball, with the example using logging and tmpnam, which was very helpful. I just wanted to ask here whether anyone else has other examples of embedding an interpreter in a C host that I could look at, or can point me at further resources or tutorials. And if anyone else is doing work in this domain, I'd love to hear about it! thanks iain

1 0

three questions regarding gambit low level
by Jörg F. Wittenberger 26 Dec '19

26 Dec '19

Hi all, once I wrote a piece of code implementing "software transactional memory". The sugar part of it is in the tests[1]: handler can be attached to the transaction. The latter feature was used to implement a small data flow language embedded in Scheme. I miss it under gambit. If there was a STM implementation for gambit, which I could start from, please tell me. It could be quite a short cut. Otherwise I need help to understand three things: 1. Atomicity in GVM To start with I could always just have a global lock instead of lock-free updates. Optimizations might be done later. (Likely crazy, but let's see.) But I wonder: how are signal handlers actually handled? Can I declare a `for-each` statement in such a way that the GVM sees no signal handler running during execution time? Also, there appears to come some multi threaded GVM our way: will this be the case in the future too? Background: the heart of the implementation is a list of in-transaction-value records, which need to be written back to the global scope atomically. 2. Defining yet another record type. Much like SRFI-9 just two actual slots per record field, the value and a version tag. Likely doable, but the tricky part: how do I hide the version tag accessors from user code? 3. For *each slot* of a record X of type Y defined using the definition from step 2, I need to be able to create another record ITV[2]. The `for-each` from #1 traverses a ist of ITV checks the version tag from ITV against X's tag and if all goes well, copies the value field from ITV to X. In the original code, ITV holds a pointer to X and an integer offset into X representation. (A low level chicken feature `##sys#slot`.) Is there something alike in gambit? Thank you so much Jörg [1] https://github.com/0-8-15/hopefully/blob/03210411161e0df057cabf9fae73468820… [2] ITV: in-transaction-value

6 11

How to return multiple "double" values from a C function ?
by Ryuho Yokoyama 22 Dec '19

22 Dec '19

[gambit-list] FFI C out parameters https://mailman.iro.umontreal.ca/pipermail/gambit-list/2015-January/007696.… According to the mailing list entry above: multiple "int" values: ---------- (c-declare " void add_mul(int x, int y, ___SCMOBJ res) { int add = x+y; int mul = x*y; ___VECTORSET(res, ___FIX(0), ___FIX(add)) ___VECTORSET(res, ___FIX(1), ___FIX(mul)) } ") (define (add-mul x y) (let ((res (vector 0 0))) ((c-lambda (int int scheme-object) void "add_mul") x y res) (values (vector-ref res 0) (vector-ref res 1)))) (receive (add mul) (add-mul 3 7) (pp (list 'add= add 'mul= mul))) ;; prints: (add= 10 mul= 21) ---------- In an example code, C function is returning multiple "int" values. How to write an example code returning multiple "double" values from a C function ? multiple "double" values: ---------- (c-declare " void add_mul(double x, double y, ___SCMOBJ res) { double add = x+y; double mul = x*y; ___F64VECTORSET(res, ___FIX(0), ___???(add)) ___F64VECTORSET(res, ___FIX(1), ___???(mul)) } ") (define (add-mul x y) (let ((res (vector 0 0))) ((c-lambda (double double scheme-object) void "add_mul") x y res) (values (vector-ref res 0) (vector-ref res 1)))) (receive (add mul) (add-mul 3.5 7.0) (pp (list 'add= add 'mul= mul))) ;; prints: (add= 10.5 mul= 24.5) ---------- ___F64VECTORSET(res, ___FIX(0), ___???(add)) ↑ ↑ ?? ?? 1) Is it possible to use ___F64VECTORSET macro instead of ___VECTORSET macro ? 2) Is it possible to define a ___F64(x) macro like a macro ___FIX(x) ? Thank you very much in advance.

2 1

Third call for draft papers for TFPIE 2020 (Trends in Functional Programming in Education)
by Jurriaan Hage 20 Dec '19

20 Dec '19

Hello, Please, find below the third call for draft papers for TFPIE 2020. Please forward these to anyone you think may be interested. Apologies for any duplicates you may receive. best regards, Jurriaan Hage Chair of TFPIE 2020 ======================================================================== TFPIE 2020 Call for papers http://www.staff.science.uu.nl/~hage0101/tfpie2020/index.html February 12th 2020, Krakow, Poland (co-located with TFP 2020 and Lambda Days) *NEW* Invited Speaker We are happy to announce the invited speaker for TFPIE 2020, Thorsten Altenkirch, who also speaks at Lambda Days. At TFPIE 2020 he shall be talking about his new book, Conceptual Programming With Python. *NEW* Registration This year TFPIE takes place outside of the Lambda Days/TFP organisation, although it takes place near their location. This means you do need to register separately for TFPIE; it also means you can register for TFPIE without registering for TFP/LambdaDays, and vice versa. Registration is mandatory for at least one author of every paper that is presented at the workshop. Only papers that have been presented at TFPIE may be submitted to the post-reviewing process. Registration is 25 euro per person. TFPIE 2020 welcomes submissions describing techniques used in the classroom, tools used in and/or developed for the classroom and any creative use of functional programming (FP) to aid education in or outside Computer Science. Topics of interest include, but are not limited to: FP and beginning CS students FP and Computational Thinking FP and Artificial Intelligence FP in Robotics FP and Music Advanced FP for undergraduates FP in graduate education Engaging students in research using FP FP in Programming Languages FP in the high school curriculum FP as a stepping stone to other CS topics FP and Philosophy The pedagogy of teaching FP FP and e-learning: MOOCs, automated assessment etc. Best Lectures - more details below In addition to papers, we are requesting best lecture presentations. What's your best lecture topic in an FP related course? Do you have a fun way to present FP concepts to novices or perhaps an especially interesting presentation of a difficult topic? In either case, please consider sharing it. Best lecture topics will be selected for presentation based on a short abstract describing the lecture and its interest to TFPIE attendees. The length of the presentation should be comparable to that of a paper. On top of the lecture itself, the presentation can also provide commentary on the lecture. Submissions Potential presenters are invited to submit an extended abstract (4-6 pages) or a draft paper (up to 20 pages) in EPTCS style. The authors of accepted presentations will have their preprints and their slides made available on the workshop's website. Papers and abstracts can be submitted via easychair at the following link: https://easychair.org/conferences/?conf=tfpie2020 . After the workshop, presenters will be invited to submit (a revised version of) their article for review. The PC will select the best articles that will be published in the Electronic Proceedings in Theoretical Computer Science (EPTCS). Articles rejected for presentation and extended abstracts will not be formally reviewed by the PC. Dates Submission deadline: January 14th 2020, Anywhere on Earth. Notification: January 17th 2020 TFPIE Registration Deadline: January 20th 2020 Workshop: February 12th 2020 Submission for formal review: April 19th 2020, Anywhere on Earth. Notification of full article: June 6th 2020 Camera ready: July 1st 2020 Program Committee Olaf Chitil - University of Kent Youyou Cong - Tokyo Institute of Technology Marko van Eekelen - Open University of the Netherlands and Radboud University Nijmegen Jurriaan Hage (Chair) - Utrecht University Marco T. Morazan - Seton Hall University, USA Sharon Tuttle - Humboldt State University, USA Janis Voigtlaender - University of Duisburg-Essen Viktoria Zsok - Eotvos Lorand University Note: information on TFP is available at http://www.cse.chalmers.se/~rjmh/tfp/

1 0

Knight's Tour Problem
by Steve Graham 05 Dec '19

05 Dec '19

Trying out a Scheme solution for this problem (), and it errored out on filter. My version of Gambit (Windows x64, 4.9.3) does not have filter. Steve

1 0

ARM64 backend status?
by Adam 03 Dec '19

03 Dec '19

What's the ARM64 backend status? I don't see it obviously from https://github.com/gambit/gambit/blob/4584611a38736ac7bbd49486a9058b5e5989c… , https://github.com/gambit/gambit/blob/master/gsc/_t-cpu-backend-arm.scm or configure. ARM64 = smartphone (For my own clarity, the compressed instruction set called ARM Thumb is a 32bit architecture only thing, ref. https://stackoverflow.com/questions/46086329/can-i-use-thumb-instructions-i… .) Thanks, Adam

1 0

planning Gambit 5
by Marc Feeley 03 Dec '19

03 Dec '19

With all the changes to Gambit recently it is time to think about Gambit v5.0.0 which will probably be released in the next 6-12 months and include some backward incompatible changes due to the evolution of the linking model for the new module system. Another backward incompatible change would be switching to multithreaded VMs by default, and the SMP scheduler. But this will require community involvement to weed out the issues and make sure it is rock solid. One backward incompatible change that could also happen at that point is a change of the default character encoding to UTF-8 (currently Gambit defaults to ISO-8859-1, aka latin-1, for all I/O unless configured otherwise with --enable-default-runtime-options=...). The nice thing about the ISO-8859-1 encoding is the 1-to-1 mapping between characters and bytes, so a program can do character I/O to read/write binary files, which was the only way to do binary I/O in the old days of Scheme (so some programs might depend on that). Nowadays many environments support UTF-8 well. Please share your thoughts... Marc

6 6