Closure is not revertible

Author: juliohm

src/transforms/closure.jl

@@ -13,19 +13,19 @@ See also [`Remainder`](@ref).
 """
 struct Closure <: StatelessFeatureTransform end
 
-isrevertible(::Type{Closure}) = true
+isrevertible(::Type{Closure}) = false
 
 assertions(::Closure) = [scitypeassert(Continuous)]
 
 function applyfeat(::Closure, feat, prep)
   cols = Tables.columns(feat)
   names = Tables.columnnames(cols)
 
-  # table as matrix and get the sum acros dims 2
+  # convert table to matrix
   X = Tables.matrix(feat)
-  S = sum(X, dims=2)
 
-  # divides each row by its sum (closure operation)
+  # divide each row by its sum (closure operation)
+  S = sum(X, dims=2)
   Z = X ./ S
 
   # table with the old columns and the new values
@@ -34,21 +34,3 @@ function applyfeat(::Closure, feat, prep)
 
   newfeat, S
 end
-
-function revertfeat(::Closure, newfeat, fcache)
-  cols = Tables.columns(newfeat)
-  names = Tables.columnnames(cols)
-
-  # table as matrix
-  Z = Tables.matrix(newfeat)
-
-  # retrieve cache
-  S = fcache
-
-  # undo operation
-  X = Z .* S
-
-  # table with original columns
-  𝒯 = (; zip(names, eachcol(X))...)
-  𝒯 |> Tables.materializer(newfeat)
-end

test/transforms/closure.jl

@@ -1,5 +1,5 @@
 @testset "Closure" begin
-  @test isrevertible(Closure())
+  @test !isrevertible(Closure())
 
   a = [2.0, 66.0, 0.0]
   b = [4.0, 22.0, 2.0]
@@ -8,7 +8,5 @@
 
   T = Closure()
   n, c = apply(T, t)
-  tₒ = revert(T, n, c)
   @test Tables.matrix(n) ≈ [0.2 0.4 0.4; 0.66 0.22 0.12; 0.00 0.02 0.98]
-  @test Tables.matrix(tₒ) ≈ Tables.matrix(t)
 end