Rank is wrong for Rational matrices

[chakravala]

@foobar_lv2

It appears like the same problem applies to integer matrices:

You could try Hermite Normal Form

Hermite normal form

The Hecke.jl library supports it

https://github.com/thofma/Hecke.jl/search?&q=hnf

As stated in the references http://nemocas.org/links.html