refactor: update for MTKv9

Author: AayushSabharwal

Project.toml

@@ -51,7 +51,7 @@ ForwardDiff = "0.10.26"
 LinearAlgebra = "1.10"
 Logging = "1.10"
 LoggingExtras = "0.4, 1"
-ModelingToolkit = "8.74"
+ModelingToolkit = "8.74, 9"
 Pkg = "1"
 Printf = "1.10"
 ProgressLogging = "0.1"

lib/OptimizationMOI/Project.toml

@@ -17,7 +17,7 @@ Symbolics = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 Ipopt_jll = "=300.1400.400"
 Juniper = "0.9"
 MathOptInterface = "1"
-ModelingToolkit = "8.74"
+ModelingToolkit = "9"
 Optimization = "3.21"
 Reexport = "1.2"
 SymbolicIndexingInterface = "0.3"

lib/OptimizationMOI/src/OptimizationMOI.jl

@@ -6,7 +6,7 @@ using MathOptInterface
 using Optimization.SciMLBase
 using SymbolicIndexingInterface
 using SparseArrays
-import ModelingToolkit: parameters, states, varmap_to_vars, mergedefaults, toexpr
+import ModelingToolkit: parameters, unknowns, varmap_to_vars, mergedefaults, toexpr
 import ModelingToolkit
 const MTK = ModelingToolkit
 using Symbolics
@@ -182,12 +182,12 @@ end
 """
     convert_to_expr(eq, sys; expand_expr = false, pairs_arr = expr_map(sys))
 
-Converts the given symbolic expression to a Julia `Expr` and replaces all symbols, i.e. states and
+Converts the given symbolic expression to a Julia `Expr` and replaces all symbols, i.e. unknowns and
 parameters with `x[i]` and `p[i]`.
 
 # Arguments:
 - `eq`: Expression to convert
-- `sys`: Reference to the system holding the parameters and states
+- `sys`: Reference to the system holding the parameters and unknowns
 - `expand_expr=false`: If `true` the symbolic expression is expanded first.
 """
 function convert_to_expr(eq, expr_map; expand_expr = false)
@@ -206,7 +206,7 @@ function convert_to_expr(eq, expr_map; expand_expr = false)
 end
 
 function get_expr_map(sys)
-    dvs = ModelingToolkit.states(sys)
+    dvs = ModelingToolkit.unknowns(sys)
     ps = ModelingToolkit.parameters(sys)
     return vcat([ModelingToolkit.toexpr(_s) => Expr(:ref, :x, i)
                  for (i, _s) in enumerate(dvs)],