feat!: do not scalarize parameters, fix some tests

NEWS.md

@@ -45,3 +45,7 @@
     equations. For example, `[p[1] => 1.0, p[2] => 2.0]` is no longer allowed in default equations, use
     `[p => [1.0, 2.0]]` instead. Also, array equations like for `@variables u[1:2]` have `D(u) ~ A*u` as an
     array equation. If the scalarized version is desired, use `scalarize(u)`.
+  - Parameter dependencies are now supported. They can be specified using the syntax
+    `(single_parameter => expression_involving_other_parameters)` and a `Vector` of these can be passed to
+    the `parameter_dependencies` keyword argument of `ODESystem`, `SDESystem` and `JumpSystem`. The dependent
+    parameters are updated whenever other parameters are modified, e.g. in callbacks.

src/ModelingToolkit.jl

@@ -36,7 +36,7 @@ using PrecompileTools, Reexport
     using RecursiveArrayTools
 
     using SymbolicIndexingInterface
-    export independent_variables, unknowns, parameters
+    export independent_variables, unknowns, parameters, full_parameters
     import SymbolicUtils
     import SymbolicUtils: istree, arguments, operation, similarterm, promote_symtype,
                           Symbolic, isadd, ismul, ispow, issym, FnType,

src/bipartite_graph.jl

@@ -88,7 +88,8 @@ function Base.push!(m::Matching, v)
     end
 end
 
-function complete(m::Matching{U}, N = maximum((x for x in m.match if isa(x, Int)); init=0)) where {U}
+function complete(m::Matching{U},
+        N = maximum((x for x in m.match if isa(x, Int)); init = 0)) where {U}
     m.inv_match !== nothing && return m
     inv_match = Union{U, Int}[unassigned for _ in 1:N]
     for (i, eq) in enumerate(m.match)

src/structural_transformation/partial_state_selection.jl

@@ -51,7 +51,7 @@ function pss_graph_modia!(structure::SystemStructure, maximal_top_matching, varl
         old_level_vars = ()
         ict = IncrementalCycleTracker(
             DiCMOBiGraph{true}(graph,
-			       complete(Matching(ndsts(graph)), nsrcs(graph))),
+                complete(Matching(ndsts(graph)), nsrcs(graph))),
             dir = :in)
 
         while level >= 0

src/systems/abstractsystem.jl

@@ -192,8 +192,7 @@
         ic = get_index_cache(sys)
         h = getsymbolhash(sym)
         return haskey(ic.unknown_idx, h) ||
-               haskey(ic.unknown_idx, getsymbolhash(default_toterm(sym))) ||
-               hasname(sym) && is_variable(sys, getname(sym))
+               haskey(ic.unknown_idx, getsymbolhash(default_toterm(sym)))
     else
         return any(isequal(sym), variable_symbols(sys)) ||
                hasname(sym) && is_variable(sys, getname(sym))
@@ -220,8 +219,6 @@
             h = getsymbolhash(default_toterm(sym))
             if haskey(ic.unknown_idx, h)
                 ic.unknown_idx[h]
-            elseif hasname(sym)
-                variable_index(sys, getname(sym))
             else
                 nothing
             end
@@ -264,8 +261,7 @@
         else
             h = getsymbolhash(default_toterm(sym))
             haskey(ic.param_idx, h) || haskey(ic.discrete_idx, h) ||
-                haskey(ic.constant_idx, h) || haskey(ic.dependent_idx, h) ||
-                hasname(sym) && is_parameter(sys, getname(sym))
+                haskey(ic.constant_idx, h) || haskey(ic.dependent_idx, h)
         end
     end
     return any(isequal(sym), parameter_symbols(sys)) ||
@@ -286,27 +282,12 @@
     if has_index_cache(sys) && get_index_cache(sys) !== nothing
         ic = get_index_cache(sys)
         h = getsymbolhash(sym)
-        return if haskey(ic.param_idx, h)
-            ParameterIndex(SciMLStructures.Tunable(), ic.param_idx[h])
-        elseif haskey(ic.discrete_idx, h)
-            ParameterIndex(SciMLStructures.Discrete(), ic.discrete_idx[h])
-        elseif haskey(ic.constant_idx, h)
-            ParameterIndex(SciMLStructures.Constants(), ic.constant_idx[h])
-        elseif haskey(ic.dependent_idx, h)
-            ParameterIndex(nothing, ic.dependent_idx[h])
+        return if (idx = ParameterIndex(ic, sym)) !== nothing
+            idx
+        elseif (idx = ParameterIndex(ic, default_toterm(sym))) !== nothing
+            idx
         else
-            h = getsymbolhash(default_toterm(sym))
-            if haskey(ic.param_idx, h)
-                ParameterIndex(SciMLStructures.Tunable(), ic.param_idx[h])
-            elseif haskey(ic.discrete_idx, h)
-                ParameterIndex(SciMLStructures.Discrete(), ic.discrete_idx[h])
-            elseif haskey(ic.constant_idx, h)
-                ParameterIndex(SciMLStructures.Constants(), ic.constant_idx[h])
-            elseif haskey(ic.dependent_idx, h)
-                ParameterIndex(nothing, ic.dependent_idx[h])
-            else
-                nothing
-            end
+            nothing
         end
     end
 
@@ -329,7 +310,7 @@
 end
 
 function SymbolicIndexingInterface.parameter_symbols(sys::AbstractSystem)
-    return parameters(sys)
+    return full_parameters(sys)
 end
 
 function SymbolicIndexingInterface.is_independent_variable(sys::AbstractSystem, sym)
@@ -419,6 +400,7 @@
              :metadata
              :gui_metadata
              :discrete_subsystems
+             :parameter_dependencies
              :solved_unknowns
              :split_idxs
              :parent
@@ -703,9 +685,12 @@
             # metadata from the rescoped variable
             rescoped = renamespace(n, O)
             similarterm(O, operation(rescoped), renamed,
-                metadata = metadata(rescoped))::T
+                metadata = metadata(rescoped))
+        elseif Symbolics.isarraysymbolic(O)
+            # promote_symtype doesn't work for array symbolics
+            similarterm(O, operation(O), renamed, symtype(O), metadata = metadata(O))
         else
-            similarterm(O, operation(O), renamed, metadata = metadata(O))::T
+            similarterm(O, operation(O), renamed, metadata = metadata(O))
         end
     elseif isvariable(O)
         renamespace(n, O)
@@ -747,7 +732,29 @@
         ps = first.(ps)
     end
     systems = get_systems(sys)
-    unique(isempty(systems) ? ps : [ps; reduce(vcat, namespace_parameters.(systems))])
+    result = unique(isempty(systems) ? ps :
+                    [ps; reduce(vcat, namespace_parameters.(systems))])
+    if has_parameter_dependencies(sys) &&
+       (pdeps = get_parameter_dependencies(sys)) !== nothing
+        filter(result) do sym
+            !haskey(pdeps, sym)
+        end
+    else
+        result
+    end
+end
+
+function dependent_parameters(sys::AbstractSystem)
+    if has_parameter_dependencies(sys) &&
+       (pdeps = get_parameter_dependencies(sys)) !== nothing
+        collect(keys(pdeps))
+    else
+        []
+    end
+end
+
+function full_parameters(sys::AbstractSystem)
+    vcat(parameters(sys), dependent_parameters(sys))
 end
 
 # required in `src/connectors.jl:437`
@@ -1518,13 +1525,12 @@
     sys = ssys
     x0 = merge(defaults(sys), Dict(missing_variable_defaults(sys)), op)
     u0, _p, _ = get_u0_p(sys, x0, p; use_union = false, tofloat = true)
+    ps = parameters(sys)
     if has_index_cache(sys) && get_index_cache(sys) !== nothing
         p = MTKParameters(sys, p)
-        ps = reorder_parameters(sys, parameters(sys))
     else
         p = _p
         p, split_idxs = split_parameters_by_type(p)
-        ps = parameters(sys)
         if p isa Tuple
             ps = Base.Fix1(getindex, ps).(split_idxs)
             ps = (ps...,) #if p is Tuple, ps should be Tuple
@@ -1610,7 +1616,7 @@
         kwargs...)
     sts = unknowns(sys)
     t = get_iv(sys)
-    ps = parameters(sys)
+    ps = full_parameters(sys)
     p = reorder_parameters(sys, ps)
 
     fun = generate_function(sys, sts, ps; expression = Val{false})[1]
@@ -2121,3 +2127,17 @@
         error("substituting symbols is not supported for $(typeof(sys))")
     end
 end
+
+function process_parameter_dependencies(pdeps, ps)
+    pdeps === nothing && return pdeps, ps
+    if pdeps isa Vector && eltype(pdeps) <: Pair
+        pdeps = Dict(pdeps)
+    elseif !(pdeps isa Dict)
+        error("parameter_dependencies must be a `Dict` or `Vector{<:Pair}`")
+    end
+
+    ps = filter(ps) do p
+        !haskey(pdeps, p)
+    end
+    return pdeps, ps
+end

src/systems/callbacks.jl

@@ -390,11 +390,8 @@
                 if has_index_cache(sys) && get_index_cache(sys) !== nothing
                     ic = get_index_cache(sys)
                     update_inds = map(update_vars) do sym
-                        @unpack portion, idx = parameter_index(sys, sym)
-                        if portion == SciMLStructures.Discrete()
-                            idx += length(ic.param_idx)
-                        end
-                        idx
+                        pind = parameter_index(sys, sym)
+                        discrete_linear_index(ic, pind)
                     end
                 else
                     psind = Dict(reverse(en) for en in enumerate(ps))
@@ -436,14 +433,14 @@
 end
 
 function generate_rootfinding_callback(sys::AbstractODESystem, dvs = unknowns(sys),
-        ps = parameters(sys); kwargs...)
+        ps = full_parameters(sys); kwargs...)
     cbs = continuous_events(sys)
     isempty(cbs) && return nothing
     generate_rootfinding_callback(cbs, sys, dvs, ps; kwargs...)
 end
 
 function generate_rootfinding_callback(cbs, sys::AbstractODESystem, dvs = unknowns(sys),
-        ps = parameters(sys); kwargs...)
+        ps = full_parameters(sys); kwargs...)
     eqs = map(cb -> cb.eqs, cbs)
     num_eqs = length.(eqs)
     (isempty(eqs) || sum(num_eqs) == 0) && return nothing
@@ -559,7 +556,7 @@
 end
 
 function generate_discrete_callbacks(sys::AbstractSystem, dvs = unknowns(sys),
-        ps = parameters(sys); kwargs...)
+        ps = full_parameters(sys); kwargs...)
     has_discrete_events(sys) || return nothing
     symcbs = discrete_events(sys)
     isempty(symcbs) && return nothing