From 74910f34b5b5d5553a554eae387dd997ddad1156 Mon Sep 17 00:00:00 2001
From: Tommy Hofmann <thofma@gmail.com>
Date: Fri, 2 Feb 2024 19:57:21 +0100
Subject: [PATCH] fix: make dot work again (#1593)

---
 src/AbstractAlgebra.jl |  3 +++
 src/NCRings.jl         | 12 ++++++++++++
 src/NemoStuff.jl       |  3 ---
 test/NCRings-test.jl   | 19 +++++++++++++++++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/src/AbstractAlgebra.jl b/src/AbstractAlgebra.jl
index da7ee3039c..f4641e03c7 100644
--- a/src/AbstractAlgebra.jl
+++ b/src/AbstractAlgebra.jl
@@ -28,7 +28,10 @@ const import_exclude = [:import_exclude, :QQ, :ZZ,
 # imported here and in Generic.jl, and exported below.
 # They should not be imported/exported anywhere else.
 
+import LinearAlgebra
+
 import LinearAlgebra: det
+import LinearAlgebra: dot
 import LinearAlgebra: hessenberg
 import LinearAlgebra: ishermitian
 import LinearAlgebra: issymmetric
diff --git a/src/NCRings.jl b/src/NCRings.jl
index d8f2953ec0..a95daf9f1e 100644
--- a/src/NCRings.jl
+++ b/src/NCRings.jl
@@ -290,3 +290,15 @@ Base.oftype(x::NCRingElem, y::Rational) = parent(x)(y)
 ###############################################################################
 
 Base.broadcastable(x::NCRingElem) = Ref(x)
+
+################################################################################
+#
+#   Dot
+#
+################################################################################
+
+dot(x::NCRingElem, y::NCRingElem) = x * y
+
+dot(x::NCRingElem, y::Union{Integer, Rational, AbstractFloat}) = x * y
+
+dot(x::Union{Integer, Rational, AbstractFloat}, y::NCRingElem) = x * y
diff --git a/src/NemoStuff.jl b/src/NemoStuff.jl
index 8a4052fda0..b6cb93fd99 100644
--- a/src/NemoStuff.jl
+++ b/src/NemoStuff.jl
@@ -398,9 +398,6 @@ end
 
 Random.gentype(::Type{T}) where {T<:FinField} = elem_type(T)
 
-import LinearAlgebra
-LinearAlgebra.dot(a::NCRingElem, b::NCRingElem) = a * b
-
 transpose!(A::MatrixElem) = transpose(A)
 
 function Base.div(f::PolyRingElem, g::PolyRingElem)
diff --git a/test/NCRings-test.jl b/test/NCRings-test.jl
index 530443fc5b..5f77883996 100644
--- a/test/NCRings-test.jl
+++ b/test/NCRings-test.jl
@@ -56,3 +56,22 @@ end
    M = matrix_space(ZZ, 2, rand(3:9))
    @test_throws DomainError powers(rand(M, 1:9), rand(1:9))
 end
+
+@testset "dot" begin
+  dot = AbstractAlgebra.LinearAlgebra.dot
+
+  Qx, x  = QQ["x"]
+  @test dot([x, x^2], [1, 1]) == x + x^2
+  @test dot([x, x^2], Rational{BigInt}[1, 1]) == x + x^2
+  @test dot([1, 1], [x, x^2]) == x + x^2
+  @test dot(Rational{BigInt}[1, 1], [x, x^2]) == x + x^2
+  @test dot([x], [x^2]) == x^3
+
+  R = matrix_ring(QQ, 2)
+  x = R([1 2; 3 4])
+  @test dot([x, x^2], [1, 1]) == x + x^2
+  @test dot([x, x^2], Rational{BigInt}[1, 1]) == x + x^2
+  @test dot([1, 1], [x, x^2]) == x + x^2
+  @test dot(Rational{BigInt}[1, 1], [x, x^2]) == x + x^2
+  @test dot([x], [x^2]) == x^3
+end