add forward for FlattenLayerOp

Project.toml

@@ -11,7 +11,7 @@ Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 
 [compat]
-ControllerFormats = "0.2"
+ControllerFormats = "0.2.3"
 LazySets = "2.13"
 LinearAlgebra = "<0.0.1, 1.6"
 ReachabilityBase = "0.2.1"

src/ForwardAlgorithms/DefaultForward.jl

@@ -22,6 +22,11 @@ function forward(X::AbstractSingleton, net::FeedforwardNetwork, ::ForwardAlgorit
     return forward(X, net, DefaultForward())
 end
 
+# flattening a ConvSet just unwraps the set
+function forward(cs::ConvSet, ::FlattenLayerOp, ::ForwardAlgorithm=DefaultForward())
+    return cs.set
+end
+
 # propagate singleton through network and store all intermediate results
 function _forward_store(X::AbstractSingleton, net::FeedforwardNetwork,
                         algo::DefaultForward=DefaultForward())

src/ForwardAlgorithms/ForwardAlgorithms.jl

@@ -1,5 +1,6 @@
 module ForwardAlgorithms
 
+using ..Util
 using LinearAlgebra: Diagonal
 using ControllerFormats
 using LazySets

test/ForwardAlgorithms/forward.jl

@@ -366,3 +366,10 @@ end
     # not supported yet
     @test_broken forward(X, N, Verisig())
 end
+
+@testset "Forward flattening layer" begin
+    S = Singleton(1:8)
+    dims = (2, 2, 2)
+    cs = ConvSet(S, dims)
+    @test forward(cs, FlattenLayerOp()) == S
+end