Added permutedims docs and tests.

base/multidimensional.jl

@@ -1466,6 +1466,11 @@ end
 
 ## Permute array dims ##
 
+"""
+    permutedims(v::AbstractVector)
+
+Reshapes vector `v` into a `1 × length(v)` row matrix.
+"""
 permutedims(v::AbstractVector) = reshape(v, (1, length(v)))
 
 function permutedims(B::StridedArray, perm = (2,1))

base/permuteddimsarray.jl

@@ -77,11 +77,11 @@ end
 @inline genperm(I, perm::AbstractVector{Int}) = genperm(I, (perm...,))
 
 """
-    permutedims(A, perm)
+    permutedims(A::AbstractArray, [perm = (2,1)])
 
 Permute the dimensions of array `A`. `perm` is a vector specifying a permutation of length
-`ndims(A)`. This is a generalization of transpose for multi-dimensional arrays. Transpose is
-equivalent to `permutedims(A, [2,1])`.
+`ndims(A)`. This is a generalization of matrix transposition for multi-dimensional arrays.
+The value of `perm` defaults to `(2,1)` for transposing the elements of a matrix
 
 See also: [`PermutedDimsArray`](@ref).
 
@@ -108,7 +108,7 @@ julia> permutedims(A, [3, 2, 1])
  6  8
 ```
 """
-function Base.permutedims(A::AbstractArray, perm)
+function Base.permutedims(A::AbstractArray, perm = (2,1))
     dest = similar(A, genperm(indices(A), perm))
     permutedims!(dest, A, perm)
 end

test/arrayops.jl

@@ -577,6 +577,12 @@ end
         @test isequal(A,permutedims(permutedims(A,perm),invperm(perm)))
         @test isequal(A,permutedims(permutedims(A,invperm(perm)),perm))
     end
+
+    m = [1 2; 3 4]
+    @test permutedims(m) == [1 3; 2 4]
+
+    v = [1,2,3]
+    @test permutedims(v) = [1 2 3]
 end
 
 @testset "circshift" begin