add option to set state priority as argument to structural_simplify and friends

Author: baggepinnen

src/systems/abstractsystem.jl

@@ -1285,6 +1285,16 @@ function markio!(state, orig_inputs, inputs, outputs; check = true)
     state, orig_inputs
 end
 
+function set_priorities!(state, priorities)
+    fullvars = state.fullvars
+    for (i, v) in enumerate(fullvars)
+        if v in keys(priorities)
+            v = setmetadata(v, VariableStatePriority, priorities[v])
+            fullvars[i] = v
+        end
+    end
+end
+
 """
     (; A, B, C, D), simplified_sys = linearize(sys, inputs, outputs;    t=0.0, op = Dict(), allow_input_derivatives = false, kwargs...)
     (; A, B, C, D)                 = linearize(simplified_sys, lin_fun; t=0.0, op = Dict(), allow_input_derivatives = false)

src/systems/systemstructure.jl

@@ -521,12 +521,13 @@ function structural_simplify!(state::TearingState, io = nothing; simplify = fals
 end
 
 function _structural_simplify!(state::TearingState, io; simplify = false,
-                               check_consistency = true, kwargs...)
+                               check_consistency = true, priorities = Dict(), kwargs...)
     has_io = io !== nothing
     orig_inputs = Set()
     if has_io
         ModelingToolkit.markio!(state, orig_inputs, io...)
     end
+    isempty(priorities) || ModelingToolkit.set_priorities!(state, priorities)
     state, input_idxs = ModelingToolkit.inputs_to_parameters!(state, io)
     sys, ag = ModelingToolkit.alias_elimination!(state; kwargs...)
     if check_consistency