Merge pull request #49 from SciML/observables

add observables test

Author: ChrisRackauckas

test/downstream/Project.toml

@@ -1,2 +1,3 @@
 [deps]
+ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
 OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"

test/downstream/observables.jl

@@ -0,0 +1,55 @@
+using ModelingToolkit, OrdinaryDiffEq, Test
+
+@parameters t σ ρ β
+@variables x(t) y(t) z(t)
+D = Differential(t)
+
+eqs = [D(x) ~ σ*(y-x),
+       D(y) ~ x*(ρ-z)-y,
+       D(z) ~ x*y - β*z]
+
+lorenz1 = ODESystem(eqs,name=:lorenz1)
+lorenz2 = ODESystem(eqs,name=:lorenz2)
+
+@variables a, α
+@parameters γ
+connections = [0 ~ lorenz1.x + lorenz2.y + a*γ,
+               α ~ 2lorenz1.x + a*γ]
+connected = structural_simplify(ODESystem(connections,t,[a,α],[γ],systems=[lorenz1,lorenz2]))
+
+u0 = [lorenz1.x => 1.0,
+      lorenz1.y => 0.0,
+      lorenz1.z => 0.0,
+      lorenz2.x => 0.0,
+      lorenz2.y => 1.0,
+      lorenz2.z => 0.0,
+      a => 2.0]
+
+p  = [lorenz1.σ => 10.0,
+      lorenz1.ρ => 28.0,
+      lorenz1.β => 8/3,
+      lorenz2.σ => 10.0,
+      lorenz2.ρ => 28.0,
+      lorenz2.β => 8/3,
+      γ => 2.0]
+
+tspan = (0.0,100.0)
+prob = ODEProblem(connected,u0,tspan,p)
+sol = solve(prob,Rodas4())
+
+@test sol[lorenz1.x] isa Vector
+@test sol[lorenz1.x,2] isa Float64
+@test sol[lorenz1.x,:] isa Vector
+@test length(sol[lorenz1.x,1:5]) == 5
+@test sol[α] isa Vector
+@test sol[α,3] isa Float64
+@test length(sol[α,5:10]) == 6
+
+#=
+using Plots
+plot(sol,vars=(lorenz2.x,lorenz2.z))
+plot(sol,vars=(α,lorenz2.z))
+plot(sol,vars=(lorenz2.x,α))
+plot(sol,vars=α)
+plot(sol,vars=(t,α))
+=#