Add real/imag (#251)

* Add real/imag

* Add tests

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFunBase"
 uuid = "fbd15aa5-315a-5a7d-a8a4-24992e37be05"
-version = "0.7.28"
+version = "0.7.29"
 
 [deps]
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"

src/ApproxFunBase.jl

@@ -23,7 +23,7 @@ import Base: values, convert, getindex, setindex!, *, +, -, ==, <, <=, >, |, !,
                 isless, union, angle, join, isnan, isapprox, isempty, sort, merge, promote_rule,
                 minimum, maximum, extrema, argmax, argmin, findmax, findmin, isfinite,
                 zeros, zero, one, promote_rule, repeat, length, resize!, isinf,
-                getproperty, findfirst, unsafe_getindex, fld, cld, div, imag,
+                getproperty, findfirst, unsafe_getindex, fld, cld, div,
                 @_inline_meta, eachindex, firstindex, lastindex, keys, isreal, OneTo,
                 Array, Vector, Matrix, view, ones, @propagate_inbounds, print_array,
                 split, iszero, permutedims, rad2deg, deg2rad

src/Operators/general/ReImSpace.jl

@@ -0,0 +1,33 @@
+## just takes realpart of operator
+struct ReOperator{O,T} <: Operator{T}
+    op::O
+end
+
+ReOperator(op)=ReOperator{typeof(op),real(eltype(op))}(op)
+convert(::Type{Operator{T}},R::ReOperator) where {T} = ReOperator{typeof(R.op),T}(R.op)
+
+@wrapperstructure ReOperator
+@wrapperspaces ReOperator
+
+
+
+
+
+getindex(RI::ReOperator{O,T},k::Integer,j::Integer) where {O,T} =
+    convert(T,real(RI.op[k,j]))
+
+choosedomainspace(R::ReOperator,sp::Space) = choosedomainspace(R.op,sp)
+for OP in (:promotedomainspace,:promoterangespace)
+    @eval begin
+        $OP(R::ReOperator,sp::UnsetSpace) = ReOperator($OP(R.op,sp))
+        $OP(R::ReOperator,sp::Space) = ReOperator($OP(R.op,sp))
+    end
+end
+
+
+
+# TODO: can't do this because UnsetSpace might change type
+#real{T<:Real}(op::Operator{T})=op
+real(op::Operator) = ReOperator(op)
+imag(op::Operator) = real(-im * op)
+conj(op::Operator) = real(op) - im * imag(op)

src/Operators/general/general.jl

@@ -5,3 +5,4 @@ include("OperatorLayout.jl")
 include("PartialInverseOperator.jl")
 include("InterlaceOperator.jl")
 include("OperatorFunction.jl")
+include("ReImSpace.jl")

test/runtests.jl

@@ -268,6 +268,25 @@ end
         M = Multiplication(Fun(identity, PointSpace(1:3)))
         @test_throws ErrorException Matrix(M)
     end
+    @testset "real-imag" begin
+        A = (3 + 2im)*I : PointSpace(1:4)
+        Ar = ApproxFunBase.real(A)
+        Ai = imag(A)
+        @test Ar[1:4, 1:4] == diagm(0=>fill(3, 4))
+        @test Ai[1:4, 1:4] == diagm(0=>fill(2, 4))
+        B = conj(A)
+        Bi = imag(B)
+        @test Bi[1:4, 1:4] == diagm(0=>fill(-2, 4))
+        C = convert(Operator{ComplexF64}, A)
+        @test C isa Operator{ComplexF64}
+        @test imag(C)[1:4, 1:4] == diagm(0=>fill(2, 4))
+
+        A = (3 - 2im)*I : PointSpace(1:4)
+        Ar = ApproxFunBase.real(A)
+        Ai = imag(A)
+        @test Ar[1:4, 1:4] == diagm(0=>fill(3, 4))
+        @test Ai[1:4, 1:4] == diagm(0=>fill(-2, 4))
+    end
 end
 
 @testset "RowVector" begin