Add Subintegrator Nodes

src/OrdinaryDiffEqOperatorSplitting.jl

@@ -11,13 +11,15 @@ import SciMLBase: DEIntegrator, NullParameters, isadaptive
 
 import RecursiveArrayTools
 
-import OrdinaryDiffEqCore
+import OrdinaryDiffEqCore: OrdinaryDiffEqCore, isdtchangeable,
+    stepsize_controller!, step_accept_controller!, step_reject_controller!
 
 abstract type AbstractOperatorSplitFunction <: SciMLBase.AbstractODEFunction{true} end
 abstract type AbstractOperatorSplittingAlgorithm end
 abstract type AbstractOperatorSplittingCache end
 
 @inline SciMLBase.isadaptive(::AbstractOperatorSplittingAlgorithm) = false
+@inline isdtchangeable(alg::AbstractOperatorSplittingAlgorithm) = all(isdtchangeable.(alg.inner_algs))
 
 include("function.jl")
 include("problem.jl")

src/function.jl

@@ -13,11 +13,24 @@ struct GenericSplitFunction{fSetType <: Tuple, idxSetType <: Tuple, sSetType <:
     # Operators to update the ode function parameters.
     synchronizers::sSetType
     function GenericSplitFunction(fs::Tuple, drs::Tuple, syncers::Tuple)
-        @assert length(fs) == length(drs) == length(syncers)
+        @assert length(fs) == length(drs) == length(syncers) "Number of input tuples does not match."
+        gsf_recursive_function_type_safety_check.(fs)
         return new{typeof(fs), typeof(drs), typeof(syncers)}(fs, drs, syncers)
     end
 end
 
+function gsf_recursive_function_type_safety_check(f::GenericSplitFunction)
+    return gsf_recursive_function_type_safety_check.(f.functions)
+end
+
+function gsf_recursive_function_type_safety_check(dunno)
+    return @warn "One of the inner functions in GenericSplitFunction is of type $(typeof(dunno)) which is not a subtype of SciMLBase.AbstractDiffEqFunction."
+end
+
+function gsf_recursive_function_type_safety_check(::SciMLBase.AbstractDiffEqFunction)
+    # OK
+end
+
 num_operators(f::GenericSplitFunction) = length(f.functions)
 
 """