Add pseudo-inverse of tensors and enable tranpose for Vec{dim}

src/Tensors.jl

@@ -72,7 +72,7 @@ end
 ###############
 # Typealiases #
 ###############
-const Vec{dim, T, M} = Tensor{1, dim, T, dim}
+const Vec{dim, T} = Tensor{1, dim, T, dim}
 
 const AllTensors{dim, T} = Union{SymmetricTensor{2, dim, T}, Tensor{2, dim, T},
                                  SymmetricTensor{4, dim, T}, Tensor{4, dim, T},

src/math_ops.jl

@@ -155,6 +155,31 @@ function Base.inv(t::SymmetricTensor{4, dim, T}) where {dim, T}
     frommandel(SymmetricTensor{4, dim}, inv(tomandel(t)))
 end
 
+"""
+    inv(::Tensor{order, dim})
+
+Compute the pseudo-inverse of a tensor.
+"""
+function LinearAlgebra.pinv(t::Vec{dim, T}) where {dim, T}
+    LinearAlgebra.Transpose{T, Vec{dim, T}}(t / sum(t.^2))
+end
+
+function LinearAlgebra.pinv(t::Tensor{2, dim}) where {dim}
+    Base.inv(t)
+end
+
+function LinearAlgebra.pinv(t::SymmetricTensor{2, dim}) where {dim}
+    Base.inv(t)
+end
+
+function LinearAlgebra.pinv(t::Tensor{4, dim}) where {dim}
+    Base.inv(t)
+end
+
+function LinearAlgebra.pinv(t::SymmetricTensor{4, dim, T}) where {dim, T}
+    Base.inv(t)
+end
+
 Base.:\(S1::SecondOrderTensor, S2::AbstractTensor) = inv(S1) ⋅ S2
 
 """

src/tensor_ops_errors.jl

@@ -1,10 +1,4 @@
 # Remove `*` as infix operator between tensors
 function Base.:*(S1::AbstractTensor, S2::AbstractTensor)
     error("use `⋅` (`\\cdot`) for single contraction and `⊡` (`\\boxdot`) for double contraction instead of `*`")
-end
-
-for f in (:transpose, :adjoint)
-    @eval function LinearAlgebra.$f(::Vec)
-        throw(ArgumentError("the (no-op) $($f) is discontinued for `Tensors.Vec`"))
-    end
-end
+end

test/test_misc.jl

@@ -545,10 +545,4 @@ end
     A2 = rand(Tensor{2, 2})
     @test_throws DimensionMismatch A + A2
     @test_throws DimensionMismatch AA - A
-
-    # transpose/adjoint of Vec
-    x = rand(Vec{3})
-    @test_throws ArgumentError x'
-    @test_throws ArgumentError transpose(x)
-    @test_throws ArgumentError adjoint(x)
 end # of testset