Matrix multiplication and type stability

[denshd]

Hello! Didn't get an answer on Discourse, so hope to succeed here.

Let’s consider MVE:

using LinearAlgebra
using AlgebraicNumbers


M = AlgebraicNumber.([
    1 2
    3 4
])

b = AlgebraicNumber.([5; 6])

println(typeof(M))
println(typeof(b))

x = M * b

println(typeof(x))

Expected a Vector{AlgebraicNumber...}, not Vector{Any}, just like in this example:

using LinearAlgebra
using AlgebraicNumbers


M = Rational.([
    1 2
    3 4
])

b = Rational.([5; 6])

println(typeof(M))
println(typeof(b))

x = M * b

println(typeof(x))

That’s interesting that it works just fine with functions like det and tr, but not with matrix multiplication.

So, my question is: is it normal behavior? And if so, how should I perform this operation in order to get Vector{AlgebraicNumber...}? Should I just use conversion from type Any?

[fkastner]

Hi,
many thanks for using the package and for reporting this issue!
This is not normal behaviour and was caused by a type instability in the code.
I just pushed an update that should hopefully fix this.
It should be available from the registry shortly.
Please report back if it doesn't fix your issue.

[anj1]

Thanks @fkastner for looking into this.