assume only one problem

src/solver/adaptivity.jl

@@ -41,19 +41,21 @@ end
 """
     get_reaction_tangent(integrator::OS.OperatorSplittingIntegrator)
 Returns the maximal reaction magnitude using the [`PointwiseODEFunction`](@ref) of an operator splitting integrator that uses [`LieTrotterGodunov`](@ref) [Lie:1880:tti,Tro:1959:psg,God:1959:dmn](@cite).
+It is assumed that the problem containing the reaction tangent is a [`PointwiseODEFunction`](@ref).
 """
 @inline function get_reaction_tangent(integrator::OS.OperatorSplittingIntegrator)
     reaction_subintegrators = unrolled_filter(subintegrator -> subintegrator.f isa PointwiseODEFunction, integrator.subintegrators)
     isempty(reaction_subintegrators) && @error "PointwiseODEFunction not found"
     _get_reaction_tangent(reaction_subintegrators)
 end
 
-@inline @unroll function _get_reaction_tangent(subintegrators)
-    @unroll for subintegrator in subintegrators
+@inline #=@unroll=# function _get_reaction_tangent(subintegrators)
+    subintegrator = subintegrators[1]
+    # @unroll for subintegrator in subintegrators
         #TODO: It should be either all the the same type or just one subintegrator after filtering, don't unroll?
-        φₘidx = transmembranepotential_index(subintegrator.f.ode)
-        return maximum(@view subintegrator.cache.dumat[:, φₘidx])
-    end
+    φₘidx = transmembranepotential_index(subintegrator.f.ode)
+    return maximum(@view subintegrator.cache.dumat[:, φₘidx])
+    # end
 end
 
 @inline function OS.stepsize_controller!(integrator::OS.OperatorSplittingIntegrator, alg::AdaptiveOperatorSplittingAlgorithm)