August 2025 - PPL-devel - BUGSENG Mailman

Re: Disjunction of two Pointset_Powerset? (likely bug in the OCaml binding)
by BUGSENG Support 22 Sep '25

22 Sep '25

Dear Étienne, thank you for contacting us directly. The ppl-devel mailing list has been relocated under a different domain (bugseng.com), we did not receive you emails. A notice informing of the relocation has been sent to all mailing list subscribers on Jan 22. Subject was: "PPL-devel mailing list relocation". Please, see the new PPL-devel home at: https://support.bugseng.com/cgi-bin/mailman/listinfo/ppl-devel Thank you for the bug report, we will look at it as soon as possible. Can you please share with us a testcase to reproduce the error? Do you have any additional information that might be helpful? Thank you, regards Federico On 08/11/24 14:00, Étienne André wrote: > Dear PPL developers, > > I received a "mailer daemon" in reply to my former email related to a > likely bug in the OCaml interface, so I take the liberty to write > another email (see below). > > Many thanks for your answer. > > Best, > > Étienne André > Université Sorbonne Paris Nord > https://lipn.univ-paris13.fr/~andre/ > > Le 22/10/2024 à 15:09, Étienne André a écrit : >> >> Dear PPL developers, >> >> We didn't have news since March, but we tried to investigate the >> problem, and it looks now rather likely to us that the bug mentioned >> in my first email /does/ come from a bug in PPL, more precisely from >> the OCaml binding. It is likely that some "free" operations on >> pointers in the binding are unnecessary, and cause the garbage >> collector to access some already destroyed objects, leading to >> segmentation faults. >> >> My colleagues are trying to fix the binding so as to remove the "free" >> operations, and let the OCaml garbage collector do its job naturally. >> >> We still want to point out this issue, and we do encourage you in >> investigating this matter. >> >> Best, >> >> Étienne André >> Université Sorbonne Paris Nord >> https://lipn.univ-paris13.fr/~andre/ >> >>> Em sex., 31 de mai. de 2024 às 13:34, Étienne André >>> <Andre.Etienne(a)lipn13.fr> escreveu: >>> >>> Dear PPL developers, >>> >>> I wonder whether you had received our email, and might have an >>> idea of why we encounter an issue of corrupted memory with >>> Pointset_Powerset. >>> >>> Thank you! >>> >>> Best, >>> >>> Étienne André >>> Université Sorbonne Paris Nord >>> https://lipn.univ-paris13.fr/~andre/ >>> >>> Le 18/03/2024 à 11:09, Étienne André a écrit : >>>> >>>> Dear PPL developers, >>>> >>>> We got an issue in developing IMITATOR with the PPL OCaml >>>> binding, most probably not related to a PPL bug (even if we >>>> don't fully exclude it either). >>>> >>>> Our goal is to perform the disjunction of two Pointset_Powerset, >>>> i.e., union_assign p1 p2, where p1 gets as the result the union >>>> of p1 and p2. >>>> >>>> I don't think there is a function to directly do this in PPL? If >>>> there is, which one should we use? >>>> >>>> Our algorithm is as follows: >>>> >>>> 1. get all disjuncts of p2 (using an iterator) >>>> 2. for each disjunct, add it to p1 using the PPL OCaml binding >>>> function ppl_Pointset_Powerset_NNC_Polyhedron_add_disjunct >>>> >>>> Is that the right way to do? >>>> >>>> >>>> We got dimensions exceptions, both very random (changing the >>>> input file name yields a different exception!) and with >>>> completely funny dimensions (such as 208 or 416) for a system >>>> that has only 2 dimensions, and/or segmentation faults/core dump >>>> which might come from a corrupted memory somewhere. >>>> >>>> We use OCaml 4.14.1 with (presumably) PPL 1:1.2-8.1build1. >>>> >>>> Thanks! >>>> >>>> Best, >>>> >>>> -- >>>> Étienne André >>>> Université Sorbonne Paris Nord >>>> https://lipn.univ-paris13.fr/~andre/ >>> >>> >>> >>> -- >>> att. Tomaz Gomes

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For V -> H conversion, how to provide points with noninteger coordinates?
by wundermonk＠gmail.com 18 Aug '25

18 Aug '25

Hello Roberto, Yes, applying the idea in the link works. I attach a snapshot of the key code on godbolt: https://godbolt.org/z/b9EaPMvbq I have a few follow-up queries. (1) What is the difference between if (!guarded_read(in, rational_coefficients[i])) { https://github.com/BUGSENG/PPL/blob/92d0704d3309d55f39a647595f8383b86fcd57e… and if (!guarded_read(in, d)) { https://github.com/BUGSENG/PPL/blob/92d0704d3309d55f39a647595f8383b86fcd57e… The first is for rationals and the second is for reals. Does the rationals part of the code read in separately the numerator (2) and denominator (3, say) while the reals part of the code read in a decimal, say, in this case, 0.6666666666667, directly? (2) In the code I have (link of godbolt provided), I store in rational_coefficients[ ] a double which is obtained by (double)numerator/(double)denominator. Could you please confirm that this is the canonical/right way to input points / rays with noninteger coefficients -- that is where numerator and denominator are integer type? (3) Is there an interface in PPL which accepts from the user only the integer numerator and integer denominator and within PPL converts these into appropriate rationals? The reason why I ask is that within another package (unmaintained now), PORTA, the user is able to separately enter the integer numerator and integer denominator and the code manages these "appropriately" within its internals. See for e.g., file inout.c within the PORTA package https://porta.zib.de/porta-1.4.1.zip function scan_line. As a naive end user, it appears to me that treating fractions could be compiler/OS dependent and hence user explicitly providing rational input as (double)numerator/(double)denominator could give rise to different ways in which rational_coefficients[] data structure is stored depending on the compiler/OS on which the program is run. Would it not be better and more robust to ask from the user only for the integer numerator and integer denominator and "convert" these appropriately (as the function "normalize" in PPL does) in a fashion which is independent of the OS/compiler used? Again, this is a naive question as an end user. Please let me know if my concern is not relevant here. Thank you for your help.

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Git clone error
by wundermonk＠gmail.com 14 Aug '25

14 Aug '25

Hello, I am trying to install PPL on a new machine running 24.04 LTS ubuntu. I have git version 2.43.0 https://www.bugseng.com/ppl-download/ppl-git seems to indicate that git clone should work, but I obtain the following error: :~$ git clone git://git.bugseng.com/ppl/ppl.git Cloning into 'ppl'... fatal: unable to connect to git.bugseng.com: git.bugseng.com[0: 79.60.221.62]: errno=Connection refused In an earlier exchange, Roberto suggested the following: "Again: do not use any bzip2 old distribution of PPL: use the Git version, devel branch." Thank you. Tryer

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