[FR]: implement `operate_to!!(::BigInt, ::typeof(copy), ::Int)`

[nsajko]

Issue #163 was closed with MA.operate_to!!(::BigInt, ::typeof(copy), ::BigInt) being implemented, however MA could also support Int input. Perhaps also generic Integer input. May put a PR up later.

[blegat]

Is that used or would be useful for a given package ?

[nsajko]

The motivation is such:

The package HomotopyContinuation.jl currently uses the (internal) Julia function Base.GMP.MPZ.set_si! for setting the value of a BigInt to the value of a small integer. The issue is that the small integer input to Base.GMP.MPZ.set_si! has to be Clong or narrower. On all 64-bit platforms except Windows, Clong === Int64, however on Windows we have Clong === Int32. Thus Int64 does not count as a small integer on all platforms.

Given that there is nothing specific to HomotopyContinuation.jl with these problems, I feel it would make sense to:

• Implement setting the value of a BigInt to the value of a small integer (this issue) in MA, so it could be reused instead of reimplemented across the ecosystem.

• The above is a prerequisite for implementing setting the vale of a BigInt to the value of a generic Integer in MA. After that is resolved (I have it partly implemented locally), too, I would make a PR to HomotopyContinuation to make it depend on MA, simplifying the code in HomotopyContinuation.

Related bug reports:

• InexactError on certain operating systems JuliaHomotopyContinuation/HomotopyContinuation.jl#644

• https://discourse.julialang.org/t/inexacterror-in-homotopycontinuation-jl-when-solving-a-5-body-central-configuration-system/136462

[blegat]

Thanks for helping to fix HomotopyContinuation! How is #357 addressing this ? I don't see anything Windows-specific or comparison with Clong