Added similar and other code review improvements

Author: andyferris

NEWS.md

@@ -214,7 +214,7 @@ Library improvements
 
   * Introduced a wrapper type for lazy complex conjugation of arrays, `ConjArray`.
     Currently, it is used by default for the new `RowVector` type only, and
-    enforces that both `transpose(vec)` and `ctranspose(vec)` are views not copies.
+    enforces that both `transpose(vec)` and `ctranspose(vec)` are views not copies ([#20047]).
 
 Compiler/Runtime improvements
 -----------------------------

base/linalg/conjarray.jl

@@ -37,16 +37,12 @@ linearindexing{CA <: ConjArray}(::Type{CA}) = linearindexing(parent_type(CA))
 @propagate_inbounds setindex!{T,N}(a::ConjArray{T,N}, v, i::Int) = setindex!(a.parent, conj(v), i)
 @propagate_inbounds setindex!{T,N}(a::ConjArray{T,N}, v, i::Vararg{Int,N}) = setindex!(a.parent, conj(v), i...)
 
-# TODO similar
+@inline similar{T,N}(a::ConjArray, ::Type{T}, dims::Dims{N}) = similar(parent(a), T, dims)
 
 # Currently, this is default behavior for RowVector only
-"""
-    conj(rowvector)
-
-Returns a `ConjArray` lazy view of the input, where each element is conjugated.
-"""
 @inline conj(a::ConjArray) = parent(a)
 
+# Helper functions, currently used by RowVector
 @inline _conj(a::AbstractArray) = ConjArray(a)
 @inline _conj{T<:Real}(a::AbstractArray{T}) = a
 @inline _conj(a::ConjArray) = parent(a)

base/linalg/rowvector.jl

@@ -48,10 +48,12 @@ typealias ConjRowVector{T, CV <: ConjVector} RowVector{T, CV}
 convert{T,V<:AbstractVector}(::Type{RowVector{T,V}}, rowvec::RowVector) =
     RowVector{T,V}(convert(V,rowvec.vec))
 
-# similar()
-@inline similar(rowvec::RowVector) = RowVector(similar(rowvec.vec))
-@inline similar{T}(rowvec::RowVector, ::Type{T}) = RowVector(similar(rowvec.vec, transpose_type(T)))
-# There is no resizing similar() because it would be ambiguous if the result were a Matrix or a RowVector
+# similar tries to maintain the RowVector wrapper and the parent type
+@inline similar(rowvec::RowVector) = RowVector(similar(parent(rowvec)))
+@inline similar{T}(rowvec::RowVector, ::Type{T}) = RowVector(similar(parent(rowvec), transpose_type(T)))
+
+# Resizing similar currently looses its RowVector property.
+@inline similar{T,N}(rowvec::RowVector, ::Type{T}, dims::Dims{N}) = similar(parent(rowvec), T, dims)
 
 # Basic methods
 """
@@ -84,8 +86,11 @@ julia> transpose(v)
 
 parent(rowvec::RowVector) = rowvec.vec
 
-# Strictly, these are unnecessary but will make things stabler if we introduce
-# a "view" for conj(::AbstractArray)
+"""
+    conj(rowvector)
+
+Returns a `ConjArray` lazy view of the input, where each element is conjugated.
+"""
 @inline conj(rowvec::RowVector) = RowVector(_conj(rowvec.vec))
 @inline conj{T<:Real}(rowvec::RowVector{T}) = rowvec