Copy sanity-check logic for differentials to inner constructor so that it applies to all ways of forming an ODESystem.

Author: lamorton

src/systems/diffeqs/odesystem.jl

@@ -73,8 +73,26 @@ struct ODESystem <: AbstractODESystem
     type: type of the system
     """
     connection_type::Any
+
+    function ODESystem(deqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
+        check_differentials(deqs,iv)
+        new(deqs, iv, dvs, ps, observed, tgrad, jac, Wfact, Wfact_t, name, systems, defaults, structure, connection_type)
+    end
 end
 
+function check_differentials(eqs,iv)
+    diffvars = OrderedSet()
+    for eq in eqs
+        if isdiffeq(eq)
+            lhs = eq.lhs
+            diffvar, _ = var_from_nested_derivative(eq.lhs)
+            isequal(iv, iv_from_nested_derivative(lhs)) || throw(ArgumentError("Differential variable $diffvar is not a function of independent variable $iv."))
+            diffvar in diffvars && throw(ArgumentError("The differential variable $diffvar is not unique in the system of equations."))
+            push!(diffvars, diffvar)
+        end
+    end
+end 
+
 function ODESystem(
                    deqs::AbstractVector{<:Equation}, iv, dvs, ps;
                    observed = Num[],