Add base_ring_type for MatrixElem; fix it for MatSpace (#1705)

This is a useful "inverse" for `dense_matrix_type`.
Nemocas · May 15, 2024 · a2e601d · a2e601d
1 parent 17bc758
commit a2e601d
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/src/Matrix.jl b/src/Matrix.jl
@@ -10,10 +10,12 @@
 #
 ###############################################################################
 
-base_ring_type(::Type{MatSpace{T}}) where T <: NCRingElement = parent_type(T)
+base_ring_type(::Type{<:MatSpace{T}}) where T <: NCRingElement = parent_type(T)
 
 base_ring(a::MatSpace{T}) where {T <: NCRingElement} = a.base_ring::parent_type(T)
 
+base_ring_type(::Type{<:MatrixElem{T}}) where T <: NCRingElement = parent_type(T)
+
 base_ring(a::MatrixElem{T}) where {T <: NCRingElement} = a.base_ring::parent_type(T)
 
 function check_parent(a::MatElem, b::MatElem, throw::Bool = true)

diff --git a/test/generic/Matrix-test.jl b/test/generic/Matrix-test.jl
@@ -122,6 +122,9 @@ end
    @test elem_type(S) == Generic.MatSpaceElem{elem_type(R)}
    @test elem_type(Generic.MatSpace{elem_type(R)}) == Generic.MatSpaceElem{elem_type(R)}
    @test parent_type(Generic.MatSpaceElem{elem_type(R)}) == Generic.MatSpace{elem_type(R)}
+   @test base_ring_type(Generic.MatSpace{elem_type(R)}) == typeof(R)
+   @test base_ring_type(Generic.MatSpaceElem{elem_type(R)}) == typeof(R)
+   @test base_ring_type(S) == typeof(R)
    @test base_ring(S) == R
    @test nrows(S) == 3
    @test ncols(S) == 3
@@ -132,6 +135,7 @@ end
 
    @test isa(f, MatElem)
    @test parent_type(f) == typeof(S)
+   @test base_ring_type(f) == typeof(R)
 
    g = S(2)
 
@@ -348,6 +352,8 @@ end
    @test dense_matrix_type(typeof(R)) == elem_type(S)
    @test dense_matrix_type(typeof(R(1))) == elem_type(S)
 
+   @test base_ring_type(dense_matrix_type(R)) == typeof(R)
+
    @test isa(S(), MatElem)
    @test isa(S(ZZ(1)), MatElem)
    @test isa(S(one(R)), MatElem)