planning

Planning

Library and other prerequisites (desirable)

• GMP
• Flint
• Readline
• NTL
• Singular
• Factory
• call C++ methods from Julia:
  • name mangling
  • exception handling, virtual methods are not necessary for Singular binding

Bugs encountered

• Polymake configure option in Singular doesn't work
• Julia CXX package requires Julia source build of 0.4-nightly
• Powering test fails in Nemo with Julia-0.4 (now fixed)
• https://github.com/Keno/Cxx.jl/issues/20 (workarounds exist)

Proof of concept for libsing

• Does Julia's CXX interface work? Yes.

• Does Julia's CXX require packages to be built with Clang? No.

• Can we pass Julia types to C++? Currently no. Keno is working on it. (Issue 22)

• Initialise path to Singular executable from libresources (feInitResources(const char*))

• Make use of canonical form from libfactory (canonical form)

  • there is a global context encoding the base field: Zp, ZZ, QQ, which is set before constructing canonical forms
  • CF = either is a pointer to internal CF, immediate integers (small, Zp) or a pointer to big integer or QQ
  • CF is a sparse recursive polynomial over Zp, ZZ, QQ

• Singular low level types (in libpolys):

  • element: intvec (no elementHandler)
  • element: number == void*, elementHandler: coeffs,
  • element: poly = pointer to Spolyrec, elementHandler: ring
  • all the types are pointers
  • elementHandlers pointer to separate classes with function pointers emulating "virtual method"s
  • arrays of elements:
    • numbermatrix, Handler: coeffs,
    • ideal = ideal/matrix/module/map?, Handler: ring
    • polyrec, resolution

• Make use of polys and rings from libpolys (rDefault (int, int, char **) and p_One(const ring)).

• Print ring with rWrite(ring, BOOLEAN), poly with printf p_String(poly,ring,ring).

First experiments are at Accessing Singular from Julia