re-allow vector*(1-row matrix) and transpose thereof (#20423)

* re-allow vector*(1-row matrix) and transpose (closes #20389)

Author: stevengj

base/linalg/diagonal.jl

@@ -256,16 +256,9 @@ end
 
 # Methods to resolve ambiguities with `Diagonal`
 @inline *(rowvec::RowVector, D::Diagonal) = transpose(D * transpose(rowvec))
-*(::Diagonal, ::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
-
 @inline A_mul_Bt(D::Diagonal, rowvec::RowVector) = D*transpose(rowvec)
-
-At_mul_B(rowvec::RowVector, ::Diagonal) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
-
 @inline A_mul_Bc(D::Diagonal, rowvec::RowVector) = D*ctranspose(rowvec)
 
-Ac_mul_B(rowvec::RowVector, ::Diagonal) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
-
 conj(D::Diagonal) = Diagonal(conj(D.diag))
 transpose(D::Diagonal) = D
 ctranspose(D::Diagonal) = conj(D)

base/linalg/matmul.jl

@@ -81,6 +81,13 @@ function (*){T,S}(A::AbstractMatrix{T}, x::AbstractVector{S})
     A_mul_B!(similar(x,TS,size(A,1)),A,x)
 end
 
+# these will throw a DimensionMismatch unless B has 1 row (or 1 col for transposed case):
+A_mul_Bt(a::AbstractVector, B::AbstractMatrix) = A_mul_Bt(reshape(a,length(a),1),B)
+A_mul_Bt(A::AbstractMatrix, b::AbstractVector) = A_mul_Bt(A,reshape(b,length(b),1))
+A_mul_Bc(a::AbstractVector, B::AbstractMatrix) = A_mul_Bc(reshape(a,length(a),1),B)
+A_mul_Bc(A::AbstractMatrix, b::AbstractVector) = A_mul_Bc(A,reshape(b,length(b),1))
+(*)(a::AbstractVector, B::AbstractMatrix) = reshape(a,length(a),1)*B
+
 A_mul_B!{T<:BlasFloat}(y::StridedVector{T}, A::StridedVecOrMat{T}, x::StridedVector{T}) = gemv!(y, 'N', A, x)
 for elty in (Float32,Float64)
     @eval begin

base/linalg/rowvector.jl

@@ -154,26 +154,19 @@ end
     sum(@inbounds(return rowvec[i]*vec[i]) for i = 1:length(vec))
 end
 @inline *(rowvec::RowVector, mat::AbstractMatrix) = transpose(mat.' * transpose(rowvec))
-*(vec::AbstractVector, mat::AbstractMatrix) = throw(DimensionMismatch(
-    "Cannot left-multiply a matrix by a vector")) # Should become a deprecation
 *(::RowVector, ::RowVector) = throw(DimensionMismatch("Cannot multiply two transposed vectors"))
 @inline *(vec::AbstractVector, rowvec::RowVector) = vec .* rowvec
 *(vec::AbstractVector, rowvec::AbstractVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
-*(mat::AbstractMatrix, rowvec::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
 
 # Transposed forms
 A_mul_Bt(::RowVector, ::AbstractVector) = throw(DimensionMismatch("Cannot multiply two transposed vectors"))
 @inline A_mul_Bt(rowvec::RowVector, mat::AbstractMatrix) = transpose(mat * transpose(rowvec))
-A_mul_Bt(vec::AbstractVector, mat::AbstractMatrix) = throw(DimensionMismatch(
-    "Cannot left-multiply a matrix by a vector"))
 @inline A_mul_Bt(rowvec1::RowVector, rowvec2::RowVector) = rowvec1*transpose(rowvec2)
 A_mul_Bt(vec::AbstractVector, rowvec::RowVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
 @inline A_mul_Bt(vec1::AbstractVector, vec2::AbstractVector) = vec1 * transpose(vec2)
 @inline A_mul_Bt(mat::AbstractMatrix, rowvec::RowVector) = mat * transpose(rowvec)
 
 @inline At_mul_Bt(rowvec::RowVector, vec::AbstractVector) = transpose(rowvec) * transpose(vec)
-At_mul_Bt(rowvec::RowVector, mat::AbstractMatrix) = throw(DimensionMismatch(
-    "Cannot left-multiply matrix by vector"))
 @inline At_mul_Bt(vec::AbstractVector, mat::AbstractMatrix) = transpose(mat * vec)
 At_mul_Bt(rowvec1::RowVector, rowvec2::RowVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
 @inline At_mul_Bt(vec::AbstractVector, rowvec::RowVector) = transpose(vec)*transpose(rowvec)
@@ -182,42 +175,34 @@ At_mul_Bt(vec::AbstractVector, rowvec::AbstractVector) = throw(DimensionMismatch
 @inline At_mul_Bt(mat::AbstractMatrix, rowvec::RowVector) = mat.' * transpose(rowvec)
 
 At_mul_B(::RowVector, ::AbstractVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
-At_mul_B(rowvec::RowVector, mat::AbstractMatrix) = throw(DimensionMismatch(
-    "Cannot left-multiply matrix by vector"))
 @inline At_mul_B(vec::AbstractVector, mat::AbstractMatrix) = transpose(At_mul_B(mat,vec))
 @inline At_mul_B(rowvec1::RowVector, rowvec2::RowVector) = transpose(rowvec1) * rowvec2
 At_mul_B(vec::AbstractVector, rowvec::RowVector) = throw(DimensionMismatch(
     "Cannot multiply two transposed vectors"))
 @inline At_mul_B{T<:Real}(vec1::AbstractVector{T}, vec2::AbstractVector{T}) =
     reduce(+, map(At_mul_B, vec1, vec2)) # Seems to be overloaded...
 @inline At_mul_B(vec1::AbstractVector, vec2::AbstractVector) = transpose(vec1) * vec2
-At_mul_B(mat::AbstractMatrix, rowvec::RowVector) = throw(DimensionMismatch(
-    "Cannot right-multiply matrix by transposed vector"))
 
 # Conjugated forms
 A_mul_Bc(::RowVector, ::AbstractVector) = throw(DimensionMismatch("Cannot multiply two transposed vectors"))
 @inline A_mul_Bc(rowvec::RowVector, mat::AbstractMatrix) = ctranspose(mat * ctranspose(rowvec))
-A_mul_Bc(vec::AbstractVector, mat::AbstractMatrix) = throw(DimensionMismatch("Cannot left-multiply a matrix by a vector"))
 @inline A_mul_Bc(rowvec1::RowVector, rowvec2::RowVector) = rowvec1 * ctranspose(rowvec2)
 A_mul_Bc(vec::AbstractVector, rowvec::RowVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
 @inline A_mul_Bc(vec1::AbstractVector, vec2::AbstractVector) = vec1 * ctranspose(vec2)
 @inline A_mul_Bc(mat::AbstractMatrix, rowvec::RowVector) = mat * ctranspose(rowvec)
 
 @inline Ac_mul_Bc(rowvec::RowVector, vec::AbstractVector) = ctranspose(rowvec) * ctranspose(vec)
-Ac_mul_Bc(rowvec::RowVector, mat::AbstractMatrix) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
 @inline Ac_mul_Bc(vec::AbstractVector, mat::AbstractMatrix) = ctranspose(mat * vec)
 Ac_mul_Bc(rowvec1::RowVector, rowvec2::RowVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
 @inline Ac_mul_Bc(vec::AbstractVector, rowvec::RowVector) = ctranspose(vec)*ctranspose(rowvec)
 Ac_mul_Bc(vec::AbstractVector, rowvec::AbstractVector) = throw(DimensionMismatch("Cannot multiply two transposed vectors"))
 @inline Ac_mul_Bc(mat::AbstractMatrix, rowvec::RowVector) = mat' * ctranspose(rowvec)
 
 Ac_mul_B(::RowVector, ::AbstractVector) = throw(DimensionMismatch("Cannot multiply two vectors"))
-Ac_mul_B(rowvec::RowVector, mat::AbstractMatrix) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
 @inline Ac_mul_B(vec::AbstractVector, mat::AbstractMatrix) = ctranspose(Ac_mul_B(mat,vec))
 @inline Ac_mul_B(rowvec1::RowVector, rowvec2::RowVector) = ctranspose(rowvec1) * rowvec2
 Ac_mul_B(vec::AbstractVector, rowvec::RowVector) = throw(DimensionMismatch("Cannot multiply two transposed vectors"))
 @inline Ac_mul_B(vec1::AbstractVector, vec2::AbstractVector) = ctranspose(vec1)*vec2
-Ac_mul_B(mat::AbstractMatrix, rowvec::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
 
 # Left Division #
 

base/linalg/triangular.jl

@@ -1585,7 +1585,7 @@ for (f, g) in ((:\, :A_ldiv_B!), (:Ac_ldiv_B, :Ac_ldiv_B!), (:At_ldiv_B, :At_ldi
 end
 ### Multiplication with triangle to the rigth and hence lhs cannot be transposed.
 for (f, g) in ((:*, :A_mul_B!), (:A_mul_Bc, :A_mul_Bc!), (:A_mul_Bt, :A_mul_Bt!))
-    @eval begin
+    mat != :AbstractVector && @eval begin
         function ($f)(A::$mat, B::AbstractTriangular)
             TAB = typeof(zero(eltype(A))*zero(eltype(B)) + zero(eltype(A))*zero(eltype(B)))
             AA = similar(A, TAB, size(A))
@@ -1637,25 +1637,12 @@ At_mul_Bt(A::AbstractMatrix, B::AbstractTriangular) = A_mul_Bt(A.', B)
 
 # Specializations for RowVector
 @inline *(rowvec::RowVector, A::AbstractTriangular) = transpose(A * transpose(rowvec))
-*(::AbstractTriangular, ::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
-
 @inline A_mul_Bt(rowvec::RowVector, A::AbstractTriangular) = transpose(A * transpose(rowvec))
 @inline A_mul_Bt(A::AbstractTriangular, rowvec::RowVector) = A * transpose(rowvec)
-
 @inline At_mul_Bt(A::AbstractTriangular, rowvec::RowVector) = A.' * transpose(rowvec)
-At_mul_Bt(::RowVector, ::AbstractTriangular) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
-
-At_mul_B(::AbstractTriangular, ::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
-At_mul_B(::RowVector, ::AbstractTriangular) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
-
 @inline A_mul_Bc(rowvec::RowVector, A::AbstractTriangular) = ctranspose(A * ctranspose(rowvec))
 @inline A_mul_Bc(A::AbstractTriangular, rowvec::RowVector) = A * ctranspose(rowvec)
-
 @inline Ac_mul_Bc(A::AbstractTriangular, rowvec::RowVector) = A' * ctranspose(rowvec)
-Ac_mul_Bc(::RowVector, ::AbstractTriangular) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
-
-Ac_mul_B(::AbstractTriangular, ::RowVector) = throw(DimensionMismatch("Cannot right-multiply matrix by transposed vector"))
-Ac_mul_B(::RowVector, ::AbstractTriangular) = throw(DimensionMismatch("Cannot left-multiply matrix by vector"))
 
 @inline /(rowvec::RowVector, A::Union{UpperTriangular,LowerTriangular}) = transpose(transpose(A) \ transpose(rowvec))
 @inline /(rowvec::RowVector, A::Union{UnitUpperTriangular,UnitLowerTriangular}) = transpose(transpose(A) \ transpose(rowvec))

test/linalg/rowvector.jl

@@ -104,15 +104,15 @@ end
 
     @test (rv*v) === 14
     @test (rv*mat)::RowVector == [1 4 9]
-    @test_throws DimensionMismatch [1]*reshape([1],(1,1)) # no longer permitted
+    @test [1]*reshape([1],(1,1)) == reshape([1],(1,1))
     @test_throws DimensionMismatch rv*rv
     @test (v*rv)::Matrix == [1 2 3; 2 4 6; 3 6 9]
     @test_throws DimensionMismatch v*v # Was previously a missing method error, now an error message
     @test_throws DimensionMismatch mat*rv
 
     @test_throws DimensionMismatch rv*v.'
     @test (rv*mat.')::RowVector == [1 4 9]
-    @test_throws DimensionMismatch [1]*reshape([1],(1,1)).' # no longer permitted
+    @test [1]*reshape([1],(1,1)).' == reshape([1],(1,1))
     @test rv*rv.' === 14
     @test_throws DimensionMismatch v*rv.'
     @test (v*v.')::Matrix == [1 2 3; 2 4 6; 3 6 9]
@@ -142,7 +142,7 @@ end
 
     @test_throws DimensionMismatch cz*z'
     @test (cz*mat')::RowVector == [-2im 4 9]
-    @test_throws DimensionMismatch [1]*reshape([1],(1,1))' # no longer permitted
+    @test [1]*reshape([1],(1,1))' == reshape([1],(1,1))
     @test cz*cz' === 15 + 0im
     @test_throws DimensionMismatch z*cz'
     @test (z*z')::Matrix == [2 2+2im 3+3im; 2-2im 4 6; 3-3im 6 9]
@@ -238,5 +238,18 @@ end
     @test_throws DimensionMismatch ut\rv
 end
 
+# issue #20389
+@testset "1 row/col vec*mat" begin
+    let x=[1,2,3], A=ones(1,4), y=x', B=A', C=x.*A
+        @test x*A == y'*A == x*B' == y'*B' == C
+        @test A'*x' == A'*y == B*x' == B*y == C'
+    end
+end
+@testset "complex 1 row/col vec*mat" begin
+    let x=[1,2,3]*im, A=ones(1,4)*im, y=x', B=A', C=x.*A
+        @test x*A == y'*A == x*B' == y'*B' == C
+        @test A'*x' == A'*y == B*x' == B*y == C'
+    end
+end
 
 end # @testset "RowVector"