August 2023 - Gambit-list - mailman.iro.umontreal.ca

Chudnovsky's Algorithm in Gambit Scheme - A novice's question
by Torbjörn Svensson Diaz 18 Aug '23

18 Aug '23

Hello! First of all, I don't know if this is the right place to ask this question. If you think not, please let me know. Maybe you think the question is too basic. I emphasize, it's not homework. Here's Chudnovsky's algorithm in Scheme. (define (pi (digits)) (let* ((A 13591409) (B 545140134) (C 640320) (C^3/24 (quotient (expt 640320 3) 24)) (D 12)) (define (-1^n*g n g) (if (odd? n) (- g) g)) (define (split m n) (if (= 1 (- n m)) (let* ((6n (* 6 n)) (g (* (- 6n 5) (- (+ n n) 1) (- 6n 1)))) (list g (* C^3/24 (expt n 3)) (* (-1^n*g n g) (+ (* n B) A)))) (let* ((mid (quotient (+ m n) 2)) (gpq1 (split m mid)) (gpq2 (split mid n)) (g1 (car gpq1)) (p1 (cadr gpq1)) (q1 (caddr gpq1)) (g2 (car gpq2)) (p2 (cadr gpq2)) (q2 (caddr gpq2))) (list (* g1 g2) (* p1 p2) (+ (* q1 p2) (* q2 g1)))))) (let* ((num-terms (inexact->exact (floor (+ 2 (/ digits 14.181647462))))) (sqrt-C (integer-sqrt (* C (expt 100 digits)))) (gpq (split 0 num-terms)) (g (car gpq)) (p (cadr gpq)) (q (caddr gpq))) (quotient (* p C sqrt-C) (* D (+ q (* p A))))))) ||| | |There's a C version of the same algorithm that is about sixteen times as long, so Scheme is expressive indeed. What I want to do is to compare the two implementations, ||but I get stuck and don't know how to proceed!| |First I want to write a version of the Scheme program that asks me how many digits I want to calculate and then calculate that using interpretation, but I don't manage to do that. Then I want to compile the Scheme code and see how fast it runs and how much RAM it uses. Lastly, I want to compile the C version and run it. I want to compare the performance and RAM usage in all three cases. | |Could you please help me out with the Scheme part? I guess I am supposed to use "read" somehow, but how? I am a Scheme novice. | |Best regards,| | | |-- | |Torbjörn Svensson Diaz | | |

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Profiling for memory usage
by Sven Hartrumpf 16 Aug '23

16 Aug '23

Hi. I profile Gambit-compiled programs for runtime of functions by using the "perf" tool. But how can I profile programs for memory usage (allocations) of functions? Greetings Sven

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[Call for submissions TFPiE 2024] Trends in Functional Programming in Education - January 9 2024, Seton Hall University, USA
by Peter Achten 08 Aug '23

08 Aug '23

TFPIE 2024 Call for papers https://wiki.tfpie.science.ru.nl/TFPIE2024 (January 9th 2024, West Orange, NJ, USA, co-located with TFP 2024 at Seton Hall University) TFPIE 2024 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. In addition, the speaker can provide commentary on effectiveness or student feedback. 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=tfpie2024 After the workshop, presenters are invited to submit (a revised version of) their article for the formal review. The PC will select the best articles for publication in the Electronic Proceedings in Theoretical Computer Science (EPTCS). Articles rejected for presentation and extended abstracts will not be formally reviewed by the PC. Important Dates Submission deadline: December 26th 2023, Anywhere on Earth Notification: by December 30th 2023 (Note: submissions will be evaluated on a rolling basis, so earlier submissions will receive an earlier response) TFPIE Registration Deadline: TBA Workshop: January 9th 2024 Submission for formal review: April 19th 2024, Anywhere on Earth. Notification of full article: May 24th 2024 Camera ready: June 28th 2024 Program Committee - TBD Stephen Chang (Chair) - UMass Boston, USA Registration information See https://wiki.tfpie.science.ru.nl/TFPIE2024 for updated information. Registration and attendance are mandatory for at least one author of every paper that is presented at the workshop. Presenters will have their registration fee waived. Only papers that have been presented at TFPIE may be submitted to the post-reviewing process.

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Analysis of gcc and -foptimize-sibling-calls: It seems things are good.
by Bradley Lucier 02 Aug '23

02 Aug '23

I built the current mainline gcc instrumented with --enable-coverage: heine:~/programs/gambit/gambit> /pkgs/gcc-mainline/bin/gcc -v Using built-in specs. COLLECT_GCC=/pkgs/gcc-mainline/bin/gcc COLLECT_LTO_WRAPPER=/pkgs/gcc-mainline/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../../gcc-mainline/configure --enable-coverage --enable-languages=c --disable-multilib --prefix=/pkgs/gcc-mainline --disable-werror Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230802 (experimental) (GCC) and built Gambit with heine:~/programs/gambit/gambit> gsi/gsi -v v4.9.5-3-ge059fffd 20230730151945 x86_64-pc-linux-gnu "./configure 'CC=/pkgs/gcc-mainline/bin/gcc' '--enable-single-host' '--enable-trust-c-tco'" The code to "optimize" sibling calls is split between gcc/tree-tailcall.cc (suitable_for_tail_opt_p and suitable_for_tail_call_opt_p) and gcc/calls.cc (dealt with in maybe_complain_about_tail_call). I think tree-tailcall.cc deals with target-independent transformations, while calls.cc deals with low-level, target-dependent transformations. Because of this split, and having three places where this optimization can be interrupted/reported, it's not clear to me where to place a warning. By examining the .gcov files, for gcc/tree-tailcall.cc and gcc/calls.cc I can see that every tail call in the Gambit source tree was "optimized". Brad

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