fix: fix discover parameters from parameter dependencies

Author: AayushSabharwal

src/systems/diffeqs/odesystem.jl

@@ -311,6 +311,15 @@ function ODESystem(eqs, iv; kwargs...)
             push!(algeeq, eq)
         end
     end
+    for eq in get(kwargs, :parameter_dependencies, Equation[])
+        if eq isa Pair
+            collect_vars!(allunknowns, ps, eq[1], iv)
+            collect_vars!(allunknowns, ps, eq[2], iv)
+        else
+            collect_vars!(allunknowns, ps, eq.lhs, iv)
+            collect_vars!(allunknowns, ps, eq.rhs, iv)
+        end
+    end
     for v in allunknowns
         isdelay(v, iv) || continue
         collect_vars!(allunknowns, ps, arguments(v)[1], iv)

src/systems/discrete_system/discrete_system.jl

@@ -183,6 +183,15 @@ function DiscreteSystem(eqs, iv; kwargs...)
             push!(diffvars, eq.lhs)
         end
     end
+    for eq in get(kwargs, :parameter_dependencies, Equation[])
+        if eq isa Pair
+            collect_vars!(allunknowns, ps, eq[1], iv)
+            collect_vars!(allunknowns, ps, eq[2], iv)
+        else
+            collect_vars!(allunknowns, ps, eq.lhs, iv)
+            collect_vars!(allunknowns, ps, eq.rhs, iv)
+        end
+    end
     new_ps = OrderedSet()
     for p in ps
         if iscall(p) && operation(p) === getindex

src/systems/nonlinear/nonlinearsystem.jl

@@ -170,6 +170,15 @@ function NonlinearSystem(eqs; kwargs...)
         collect_vars!(allunknowns, ps, eq.lhs, nothing)
         collect_vars!(allunknowns, ps, eq.rhs, nothing)
     end
+    for eq in get(kwargs, :parameter_dependencies, Equation[])
+        if eq isa Pair
+            collect_vars!(allunknowns, ps, eq[1], nothing)
+            collect_vars!(allunknowns, ps, eq[2], nothing)
+        else
+            collect_vars!(allunknowns, ps, eq.lhs, nothing)
+            collect_vars!(allunknowns, ps, eq.rhs, nothing)
+        end
+    end
     new_ps = OrderedSet()
     for p in ps
         if iscall(p) && operation(p) === getindex

test/parameter_dependencies.jl

@@ -325,3 +325,16 @@ end
     @test getp(sys, p1)(ps2) == 2.0
     @test getp(sys, p2)(ps2) == 4.0
 end
+
+@testset "Discovery of parameters from dependencies" begin
+    @parameters p1 p2
+    @variables x(t) y(t)
+    @named sys = ODESystem([D(x) ~ y + p2], t; parameter_dependencies = [p2 ~ 2p1])
+    @test is_parameter(sys, p1)
+    @named sys = NonlinearSystem([x * y^2 ~ y + p2]; parameter_dependencies = [p2 ~ 2p1])
+    @test is_parameter(sys, p1)
+    k = ShiftIndex(t)
+    @named sys = DiscreteSystem(
+        [x(k - 1) ~ x(k) + y(k) + p2], t; parameter_dependencies = [p2 ~ 2p1])
+    @test is_parameter(sys, p1)
+end