Inplace chebyshev transform

Author: jishnub

src/Spaces/Chebyshev/Chebyshev.jl

@@ -72,6 +72,8 @@ transform(::Chebyshev,vals::AbstractVector,plan) = plan*vals
 itransform(::Chebyshev,cfs::AbstractVector,plan) = plan*cfs
 plan_transform(::Chebyshev,vals::AbstractVector) = plan_chebyshevtransform(vals)
 plan_itransform(::Chebyshev,cfs::AbstractVector) = plan_ichebyshevtransform(cfs)
+plan_transform!(::Chebyshev, vals::AbstractVector) = plan_chebyshevtransform!(vals)
+plan_itransform!(::Chebyshev, cfs::AbstractVector) = plan_ichebyshevtransform!(cfs)
 
 ## Evaluation
 

test/ChebyshevTest.jl

@@ -1,6 +1,6 @@
 using ApproxFunOrthogonalPolynomials, ApproxFunBase, LinearAlgebra, Test
-    import ApproxFunBase: testspace, recA, recB, recC
-    import ApproxFunOrthogonalPolynomials: forwardrecurrence
+import ApproxFunBase: testspace, recA, recB, recC, transform!, itransform!
+import ApproxFunOrthogonalPolynomials: forwardrecurrence
 
 @testset "Chebyshev" begin
     @testset "Forward recurrence" begin
@@ -208,4 +208,14 @@ using ApproxFunOrthogonalPolynomials, ApproxFunBase, LinearAlgebra, Test
         @test S.a==-0.5
         @test S.b==-0.5
     end
+
+    @testset "inplace transform" begin
+        for v in Any[rand(10), rand(ComplexF64, 10)]
+            v2 = copy(v)
+            transform!(Chebyshev(), v)
+            @test transform(Chebyshev(), v2) == v
+            itransform!(Chebyshev(), v)
+            @test v2 ≈ v
+        end
+    end
 end