libsingular-julia

This is the C++ library accompanying Singular.jl. It implements the C++ interface from julia to Singular using CxxWrap.jl and libcxxwrap-julia.

This library is compiled into a Julia artifact and shipped to the user via the Julia JLL package libsingular_julia_jll. This JLL package in turn is generated from the sources in this repository and the build recipe at https://github.com/JuliaPackaging/Yggdrasil/tree/master/L/libsingular_julia.

Quick way to test changes in here

To test changes you make to the C++ code here, the quickest way is to use the run.jl script bundled in this repository. As a prerequisite, you need a working C++ compiler and of course Julia.

Start Julia from this repository as follows:

julia --project=. run.jl

This will install a few required Julia packages then build all C++ code, and finally start a Julia session with an artifact override in place which ensures that libsingular_julia_jll picks up the copy of the C++ code that was just compiled.

To verify the override works, check libsingular_julia_jll.artifact_dir; it should point at a subdirectory of the current directory.

You can then use the Julia package manager to install or dev Singular.jl, and run its test suite or perform other tests.

Building

Compiling libsingular-julia from source requires a C++ enabled compiler.

The easiest way to build it is to execute the Julia script build.jl (which in turn is also used by run.jl). For this you need to execute it in a Julia environment in which Singular_jll and CxxWrap are installed.

Alternatively, you can also link it against your own libcxxwrap-julia installation and a Singular installation, but this is more work; an incantation like the following will do it:

git clone https://github.com/oscar-system/libsingular-julia \
cmake -DJulia_PREFIX=/home/user/path/to/julia \
      -DSingular_PREFIX=/home/user/path/to/singular
      -DCMAKE_INSTALL_PREFIX=home/user/prefix/for/libsingular-julia \
      -DJlCxx_DIR=/home/user/path/to/libcxxwrap-julia/lib/cmake/JlCxx \
      -DCMAKE_BUILD_TYPE=Release \
      -S libsingular-julia -B build \

cmake --build build --config Release --target install -- -j${nproc}

Overriding the default artifacts for Singular.jl

The run.jl script takes care of everything described below, but we document it in case you need to do any of this manually for some reason.

Put the following into ~/.julia/artifacts/Overrides.toml to replace the libsingular-julia artifact:

[ae4fbd8f-ecdb-54f8-bbce-35570499b30e]
libsingular_julia = "/home/user/prefix/for/libsingular-julia"

If you were using custom versions of Singular and/or libcxxwrap-julia, then their directories used during the build need to be added as well, e.g.:

[bcd08a7b-43d2-5ff7-b6d4-c458787f915c]
Singular = "/home/user/path/to/Singular"

[3eaa8342-bff7-56a5-9981-c04077f7cee7]
libcxxwrap_julia = "/home/user/path/to/libcxxwrap-julia"