refactor: use unknowns, fix some tests

Author: AayushSabharwal

src/Blocks/analysis_points.jl

@@ -23,7 +23,7 @@ function ap_var(sys)
         # collect to turn symbolic arrays into arrays of symbols
         return length(sys.u) == 1 ? sys.u : collect(sys.u)
     end
-    x = states(sys)
+    x = unknowns(sys)
     length(x) == 1 && return x[1]
     error("Could not determine the analysis-point variable in system $(nameof(sys)). To use an analysis point, apply it to a connection between two causal blocks containing connectors of type `RealInput/RealOutput` from ModelingToolkitStandardLibrary.Blocks.")
 end

test/Blocks/test_analysis_points.jl

@@ -21,8 +21,8 @@ sys = ODESystem(eqs, t, systems = [P, C], name = :hej)
 ssys = structural_simplify(sys)
 prob = ODEProblem(ssys, [P.x => 1], (0, 10))
 sol = solve(prob, Rodas5())
-@test norm(sol[1]) >= 1
-@test norm(sol[end]) < 1e-6 # This fails without the feedback through C
+@test norm(sol.u[1]) >= 1
+@test norm(sol.u[end]) < 1e-6 # This fails without the feedback through C
 # plot(sol)
 
 matrices, _ = get_sensitivity(sys, ap)

test/Mechanical/multibody.jl

@@ -22,7 +22,7 @@ eqs = [connect(link1.TX1, cart.flange) #, force.flange)
 @named model = ODESystem(eqs, t, [], []; systems = [link1, link2, cart, fixed])
 
 sys = structural_simplify(model)
-@test length(states(sys)) == 6
+@test length(unknowns(sys)) == 6
 
 # The below code does work...
 #=

test/Mechanical/rotational.jl

@@ -30,7 +30,7 @@ using OrdinaryDiffEq: ReturnCode.Success
     sol = solve(prob, Rodas4())
     @test SciMLBase.successful_retcode(sol)
 
-    prob = DAEProblem(sys, D.(states(sys)) .=> 0.0, Pair[], (0, 10.0))
+    prob = DAEProblem(sys, D.(unknowns(sys)) .=> 0.0, Pair[], (0, 10.0))
     sol = solve(prob, DFBDF())
     @test SciMLBase.successful_retcode(sol)
     @test all(sol[inertia1.w] .== 0)
@@ -84,8 +84,8 @@ end
             sine
         ])
     sys = structural_simplify(model)
-    prob = DAEProblem(sys, D.(states(sys)) .=> 0.0,
-        [D(D(inertia2.phi)) => 1.0; D.(states(model)) .=> 0.0], (0, 10.0))
+    prob = DAEProblem(sys, D.(unknowns(sys)) .=> 0.0,
+        [D(D(inertia2.phi)) => 1.0; D.(unknowns(model)) .=> 0.0], (0, 10.0))
     sol = solve(prob, DFBDF())
     @test SciMLBase.successful_retcode(sol)
 
@@ -212,7 +212,7 @@ end
             angle_sensor
         ])
     sys = structural_simplify(model)
-    prob = DAEProblem(sys, D.(states(sys)) .=> 0.0, Pair[], (0, 10.0))
+    prob = DAEProblem(sys, D.(unknowns(sys)) .=> 0.0, Pair[], (0, 10.0))
 
     sol = solve(prob, DFBDF())
     @test SciMLBase.successful_retcode(sol)
@@ -259,7 +259,7 @@ end
     @test all(sol[rel_speed_sensor.w_rel.u] .== sol[speed_sensor.w.u])
     @test all(sol[torque_sensor.tau.u] .== -sol[inertia1.flange_b.tau])
 
-    prob = DAEProblem(sys, D.(states(sys)) .=> 0.0, Pair[], (0, 10.0))
+    prob = DAEProblem(sys, D.(unknowns(sys)) .=> 0.0, Pair[], (0, 10.0))
     sol = solve(prob, DFBDF())
     @test SciMLBase.successful_retcode(sol)
     @test all(sol[inertia1.w] .== 0)