Avoid an unnecessary allocation calling permutedims (#1931)

Author: fingolfin

src/Matrix.jl

@@ -6731,11 +6731,11 @@ function matrix(arr::AbstractVector{T}) where {T<:NCRingElement}
 end
 
 function matrix(arr::Vector{Vector{T}}) where {T<:NCRingElement}
-    return matrix(permutedims(reduce(hcat, arr), (2, 1)))
+    return matrix(permutedims(reduce(hcat, arr)))
 end
 
 function matrix(R::NCRing, arr::Vector{<:Vector})
-   return matrix(R, permutedims(reduce(hcat, arr), (2, 1)))
+   return matrix(R, permutedims(reduce(hcat, arr)))
 end
 
 @doc raw"""

src/generic/MatRing.jl

@@ -34,7 +34,7 @@ is_domain_type(::Type{MatRingElem{T}}) where T <: NCRingElement = false
 ###############################################################################
 
 function transpose(x::MatRingElem{T}) where T <: NCRingElement
-   arr = permutedims(x.entries, [2, 1])
+   arr = permutedims(x.entries)
    z = MatRingElem{T}(base_ring(x), arr)
    return z
 end

test/generic/MatRing-test.jl

@@ -518,7 +518,7 @@ end
    S = matrix_ring(R, 3)
    arr = [t + 1 t R(1); t^2 t t; t+1 t^2 R(-1)]
    A = S(arr)
-   B = S(permutedims(arr, [2, 1]))
+   B = S(permutedims(arr))
    @test transpose(A) == B
 
    # Tests over noncommutative ring

test/generic/Matrix-test.jl

@@ -1662,12 +1662,12 @@ end
    R, t = polynomial_ring(QQ, "t")
    arr = [t + 1 t R(1); t^2 t t]
    A = matrix(R, arr)
-   B = matrix(R, permutedims(arr, [2, 1]))
+   B = matrix(R, permutedims(arr))
    @test transpose(A) == B
 
    arr = [t + 1 t; t^2 t]
    A = matrix(R, arr)
-   B = matrix(R, permutedims(arr, [2, 1]))
+   B = matrix(R, permutedims(arr))
    @test transpose(A) == B
 
    # transpose input/output types are the same
@@ -2337,7 +2337,7 @@ end
    U = matrix_space(S, 3, 1)
 
    M = T([3y*a^2 + (y + 1)*a + 2y (5y+1)*a^2 + 2a + y - 1 a^2 + (-a) + 2y; (y + 1)*a^2 + 2y - 4 3y*a^2 + (2y - 1)*a + y (4y - 1)*a^2 + (y - 1)*a + 5; 2a + y + 1 (2y + 2)*a^2 + 3y*a + 3y a^2 + (-y-1)*a + (-y - 3)])
-   b = U(permutedims([4y*a^2 + 4y*a + 2y + 1 5y*a^2 + (2y + 1)*a + 6y + 1 (y + 1)*a^2 + 3y*a + 2y + 4], [2, 1]))
+   b = U(permutedims([4y*a^2 + 4y*a + 2y + 1 5y*a^2 + (2y + 1)*a + 6y + 1 (y + 1)*a^2 + 3y*a + 2y + 4]))
 
    x, d = AbstractAlgebra._solve_rational(M, b)