Fix for ODE sumtype default solver as new default

Fixes #329

Author: ChrisRackauckas

src/integrators/interface.jl

@@ -138,6 +138,33 @@ function OrdinaryDiffEqCore.perform_step!(integrator::DDEIntegrator)
     nothing
 end
 
+# DefaultCache sumtype does lazy initializations of sub-caches
+# Need to overload this function so that the history function has initialized caches
+# https://github.com/SciML/DelayDiffEq.jl/issues/329
+function OrdinaryDiffEqCore.perform_step!(integrator::DDEIntegrator, cache::OrdinaryDiffEqCore.DefaultCache, repeat_step = false)
+    algs = integrator.alg.algs
+    OrdinaryDiffEqCore.init_ith_default_cache(cache, algs, cache.current)
+    if cache.current == 1
+        integrator.history.integrator.cache.cache1 = cache.cache1
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache1), repeat_step)
+    elseif cache.current == 2
+        integrator.history.integrator.cache.cache2 = cache.cache2
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache2), repeat_step)
+    elseif cache.current == 3
+        integrator.history.integrator.cache.cache3 = cache.cache3
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache3), repeat_step)
+    elseif cache.current == 4
+        integrator.history.integrator.cache.cache4 = cache.cache4
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache4), repeat_step)
+    elseif cache.current == 5
+        integrator.history.integrator.cache.cache5 = cache.cache5
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache5), repeat_step)
+    elseif cache.current == 6
+        integrator.history.integrator.cache.cache6 = cache.cache6
+        OrdinaryDiffEqCore.perform_step!(integrator, @inbounds(cache.cache6), repeat_step)
+    end
+end
+
 # initialize the integrator
 function DiffEqBase.initialize!(integrator::DDEIntegrator)
     ode_integrator = integrator.integrator

test/interface/default.jl

@@ -0,0 +1,21 @@
+using DelayDiffEq, Test
+function delay_lotka_volterra(du, u, h, p, t)
+    # Model parameters.
+    α, β, γ, δ = p
+    # Current state.
+    x, y = u
+    # Evaluate differential equations
+    du[1] = α * h(p, t - 1; idxs=1) - β * x * y
+    du[2] = -γ * y + δ * x * y
+    return nothing
+end
+p = (1.5, 1.0, 3.0, 1.0)
+u0 = [1.0; 1.0]
+tspan = (0.0, 10.0)
+h(p, t; idxs::Int) = 1.0
+prob_dde = DDEProblem(delay_lotka_volterra, u0, h, tspan, p);
+alg = MethodOfSteps(DefaultODEAlgorithm())
+sol_dde = solve(prob_dde, alg)
+sol_dde2 = solve(prob_dde)
+
+@test sol_dde == sol_dde2

test/runtests.jl

@@ -39,6 +39,9 @@ if GROUP == "All" || GROUP == "Interface"
     @time @safetestset "Mass matrix Tests" begin
         include("interface/mass_matrix.jl")
     end
+    @time @safetestset "Default Solver Tests" begin
+        include("interface/default.jl")
+    end
     @time @safetestset "Parameterized Function Tests" begin
         include("interface/parameters.jl")
     end