libgap issues in sage 10.8 on linux

[Marc Culler]

I am building an AppImage for Sage 10.8.  I have successfully built Sage 10.8 on my manylinux docker image and I can run it on my Ubuntu 24.04 system.  But I have run into issues with libgap, and possibly other parts of sage.

First, I cannot build the documentation because segfaults occur during the doc build.  Actually there are several, many of which occur during sphinxplot.  But I was able to track down at least one segfault in gap/element.cpython-313-x86_64-linux-gnu.so.  Based on disassembly, it seems to happen in make_gap_list.

I then tried running some example code from libgap, and I get weird errors.  For example:

libgap(vector((1/3, 0.8, 3)))

produces:

GAPError: Error, Variable: <<unknown>> must have an assigned value

On my 10.7 AppImage, which was built on the same docker image, the result of that command is, as expected:

[ 0.333333, 0.8, 3. ]

For another example, the command:

libgap.AlternatingGroup(4)

produces

GAPError: Error, no method found! Error, no 1st choice method found for `AlternatingGroupCons' on 2 arguments

Again, that works fine on the 10.7 Appimage, producing the expected result:

Alt( [ 1 .. 4 ] )

And, to add one more, the command:

sage: libgap.eval('5/3 + 7*E(3)').sage()

produces:

GAPError: Error, CoeffsCyc: function is not yet defined

while the following command seems to work:

libgap.eval('5/3 + 7*E(3)')
16/3*E(3)-5/3*E(3)^2

Does anyone know anything which might give a hint about what is going on here?

- Marc

[Grégory Vanuxem]

Not related. GAP has a lot of work to be done. Particularly in the Julia GC world. It's a pity, they are not usable for example using libjulia. Inconsistent things I think. Oscar for example is not usable because of GAP through libjulia.

Bad usage

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[Dima Pasechnik]

As usual, more can be said from config.log and install.log - please share them.
All your examples just work for me.
I guess it might be a clash with GAP installed system-wide on the box,
and GAP built by Sage.
I'd be happy to try your build scripts, but I don't know where to look.

Dima

[Dima Pasechnik]

On Wed, Dec 31, 2025 at 4:48 PM Grégory Vanuxem <g.va...@gmail.com> wrote:
>
> Not related. GAP has a lot of work to be done. Particularly in the Julia GC world. It's a pity, they are not usable for example using libjulia. Inconsistent things I think. Oscar for example is not usable because of GAP through libjulia.

Oscar doesn't really rely on GAP as a backend, as far as I know.
Thus saying "Oscar is unusable because of GAP ..." doesn't make sent
to me. Anyway,
unless you run Oscar on a platform on which it's not really tested
(Windows, of Oscar from GAP),
it's hard to understand what you mean.
Oscar works just fine on Linux and macOS, is well-supported and being
worked on a lot.
(while GAP is mostly in maintainance mode as far as its core
functionalities are concerned)
Few times I needed to run Oscar, it all went very well.

Dima

> To view this discussion visit https://groups.google.com/d/msgid/sage-devel/CAHnU2dbMmFAUZuHyXW1xEOKxbewEDtN3Uv53%3DjtrMyOif_UQsg%40mail.gmail.com.

[Grégory Vanuxem]

Hello, 

Le jeu. 1 janv. 2026, 05:29, Dima Pasechnik <dim...@gmail.com> a écrit :

On Wed, Dec 31, 2025 at 4:48 PM Grégory Vanuxem <g.va...@gmail.com> wrote:
>
> Not related. GAP has a lot of work to be done. Particularly in the Julia GC world. It's a pity, they are not usable for example using libjulia. Inconsistent things I think. Oscar for example is not usable because of GAP through libjulia.

Oscar doesn't really rely on GAP as a backend, as far as I know.
Thus saying "Oscar is unusable because of GAP ..." doesn't make sent
to me.

GAP is mandatory for Oscar  (on Julia). 

Anyway,
unless you run Oscar on a platform on which it's not really tested
(Windows, of Oscar from GAP),
it's hard to understand what you mean.

 I run it in WSL.  It is may be a problem. 

Oscar works just fine on Linux and macOS, is well-supported and being
worked on a lot.
(while GAP is mostly in maintainance mode as far as its core
functionalities are concerned)
Few times I needed to run Oscar, it all went very well.

I discussed this about the memory management and future work, apparently, on Discord. And this is a point for me. GAP plays apparently with the Julia GC. 

This is not the point here I agree. Take this as a after first year idea please.

Greg

PS / Keep up the good work Dima you are doing an amazing work for sagemath. Respect and, frankly speaking, have good things for this 2026 year.