Merge pull request #318 from JuliaReach/dfcaporale/GeneralizeTimeShif…

…tFlowpipes Issue #316
JuliaReach · Aug 31, 2020 · de32b5c · de32b5c
2 parents ea1b948 + 3fca441
commit de32b5c
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Showing 5 changed files with 17 additions and 2 deletions.
diff --git a/src/Flowpipes/flowpipes.jl b/src/Flowpipes/flowpipes.jl
@@ -369,7 +369,7 @@ function linear_map(M::AbstractMatrix, fp::Flowpipe)
 end
 
 """
-    shift(fp::Flowpipe{N, ReachSet{N, ST}}, t0::Number) where {N, ST}
+    shift(fp::Flowpipe{N, <:AbstractReachSet}, t0::Number) where {N}
 
 Return the time-shifted flowpipe by the given number.
 
@@ -387,7 +387,7 @@ shifted by `t0`.
 
 See also `Shift` for the lazy counterpart.
 """
-function shift(fp::Flowpipe{N, ReachSet{N, ST}}, t0::Number) where {N, ST}
+function shift(fp::Flowpipe{N, <:AbstractReachSet}, t0::Number) where {N}
     return Flowpipe([shift(X, t0) for X in array(fp)], fp.ext)
 end
 
@@ -514,6 +514,11 @@ function project(fp::ShiftedFlowpipe, i::Int, vars::NTuple{D, M}) where {D, M<:I
     return SparseReachSet(proj, tspan(R) + t0, vars)
 end
 
+# TODO: improve using mutable ShiftedFlowpipe struct (so that we can modify t0->t0+t1)
+function shift(fp::ShiftedFlowpipe, t1::Number)
+    return ShiftedFlowpipe(shift(fp.F, t1), fp.t0)
+end
+
 # =====================================
 # Flowpipe composition with a lazy map
 # =====================================

diff --git a/src/Flowpipes/solutions.jl b/src/Flowpipes/solutions.jl
@@ -131,6 +131,10 @@ function project(sol::ReachSolution{<:AbstractFlowpipe}, dir::AbstractVector{<:A
     return project(sol.F, dir; vars=vars)
 end
 
+function shift(sol::ReachSolution{<:AbstractFlowpipe}, t0::Number)
+    return ReachSolution(shift(sol.F, t0), sol.alg, sol.ext)
+end
+
 # LazySets interface falls back to the associated flowpipe
 LazySets.dim(sol::ReachSolution) = dim(sol.F)
 LazySets.ρ(d, sol::ReachSolution{FT}) where {FT<:AbstractFlowpipe} = ρ(d, sol.F)

diff --git a/test/algorithms/ASB07.jl b/test/algorithms/ASB07.jl
@@ -44,6 +44,8 @@ end
     sol = solve(prob, alg=ASB07(δ=1e-7, max_order=3), max_jumps=2)
     @test dim(sol) == 4
     @test flowpipe(sol) isa HybridFlowpipe
+
+    @test tspan(shift(sol[1],1.0))==tspan(sol[1])+1.0
 end
 
 

diff --git a/test/algorithms/GLGM06.jl b/test/algorithms/GLGM06.jl
@@ -26,6 +26,8 @@
     sol = solve(prob, T=5.0, GLGM06(δ=0.01))
     @test dim(sol) == 5
 
+    @test tspan(shift(sol,1.0))==tspan(sol)+1.0
+
     # use approx model for "discrete-time" reachability
     sol = solve(prob, T=5.0, GLGM06(δ=0.01, approx_model=NoBloating()))
 end
diff --git a/test/algorithms/TMJets.jl b/test/algorithms/TMJets.jl
@@ -21,6 +21,8 @@
     sol = solve(prob, T=0.2, abstol=1e-11)
     @test sol.alg isa TMJets && sol.alg.abs_tol == 1e-11
 
+    @test ReachabilityAnalysis.tspan(shift(sol,1.0))==ReachabilityAnalysis.tspan(sol)+1.0
+
     # split initial conditions
     X0, S = initial_state(prob), system(prob)
     X0s = split(X0, [2, 1]) # split along direction x