fix: remove implicit dependency on MTK

Author: AayushSabharwal

src/remake.jl

@@ -273,10 +273,10 @@ function remake(prob::OptimizationProblem;
             u0 = prob.u0
         end
         if (eltype(p) <: Pair && !isempty(p)) || (eltype(u0) <: Pair && !isempty(u0)) # one is a non-empty symbolic map
-            hasproperty(prob.f, :sys) && hasfield(typeof(prob.f.sys), :ps) ||
+            isempty(parameter_symbols(prob)) &&
                 throw(ArgumentError("This problem does not support symbolic maps with `remake`, i.e. it does not have a symbolic origin." *
                                     " Please use `remake` with the `p` keyword argument as a vector of values, paying attention to parameter order."))
-            hasproperty(prob.f, :sys) && hasfield(typeof(prob.f.sys), :states) ||
+            isempty(variable_symbols(prob)) &&
                 throw(ArgumentError("This problem does not support symbolic maps with `remake`, i.e. it does not have a symbolic origin." *
                                     " Please use `remake` with the `u0` keyword argument as a vector of values, paying attention to state order."))
             p, u0 = process_p_u0_symbolic(prob, p, u0)
@@ -342,10 +342,10 @@ function remake(prob::NonlinearProblem;
             u0 = prob.u0
         end
         if (eltype(p) <: Pair && !isempty(p)) || (eltype(u0) <: Pair && !isempty(u0)) # one is a non-empty symbolic map
-            hasproperty(prob.f, :sys) && hasfield(typeof(prob.f.sys), :ps) ||
+            isempty(parameter_symbols(prob)) &&
                 throw(ArgumentError("This problem does not support symbolic maps with `remake`, i.e. it does not have a symbolic origin." *
                                     " Please use `remake` with the `p` keyword argument as a vector of values, paying attention to parameter order."))
-            hasproperty(prob.f, :sys) && hasfield(typeof(prob.f.sys), :states) ||
+            isempty(variable_symbols(prob)) &&
                 throw(ArgumentError("This problem does not support symbolic maps with `remake`, i.e. it does not have a symbolic origin." *
                                     " Please use `remake` with the `u0` keyword argument as a vector of values, paying attention to state order."))
             p, u0 = process_p_u0_symbolic(prob, p, u0)