Fix and test allocations in Rosenbrock

Author: andreasnoack

lib/OrdinaryDiffEqRosenbrock/src/rosenbrock_perform_step.jl

@@ -1240,7 +1240,7 @@ end
     linsolve_tmp = @.. du + dtd[1] * dT
     k1 = _reshape(W \ -_vec(linsolve_tmp), axes(uprev))
     # constant number for type stability make sure this is greater than num_stages
-    ks = ntuple(Returns(k1), 20)
+    ks = ntuple(Returns(k1), Val(20))
     # Loop for stages
     for stage in 2:num_stages
         u = uprev

lib/OrdinaryDiffEqRosenbrock/src/stiff_addsteps.jl

@@ -85,7 +85,7 @@ function _ode_addsteps!(k, t, uprev, u, dt, f, p, cache::RosenbrockCombinedConst
         linsolve_tmp = @.. du + dtd[1] * dT
         k1 = _reshape(W \ _vec(linsolve_tmp), axes(uprev))
         # constant number for type stability make sure this is greater than num_stages
-        ks = ntuple(Returns(k1), 20)
+        ks = ntuple(Returns(k1), Val(20))
         # Last stage affect's ks for Rodas5,5P,6P
         for stage in 2:num_stages
             u = uprev

lib/OrdinaryDiffEqRosenbrock/test/allocation_tests.jl

@@ -12,32 +12,39 @@ Currently, Rosenbrock solvers are allocating and marked with @test_broken.
 @testset "Rosenbrock Allocation Tests" begin
     # Test problem - use a simple linear problem for stiff solvers
     linear_prob = ODEProblem((u, p, t) -> -u, 1.0, (0.0, 1.0))
-    
+
     # Vector problem
     function simple_system!(du, u, p, t)
         du[1] = -0.5 * u[1]
         du[2] = -1.5 * u[2]
     end
     vector_prob = ODEProblem(simple_system!, [1.0, 1.0], (0.0, 1.0))
-    
-    # Test all exported Rosenbrock solvers for allocation-free behavior  
+
+    # Test all exported Rosenbrock solvers for allocation-free behavior
     rosenbrock_solvers = [Rosenbrock23(), Rosenbrock32(), RosShamp4(), Veldd4(), Velds4(), GRK4T(), GRK4A(),
                           Rodas3(), Rodas23W(), Rodas3P(), Rodas4(), Rodas42(), Rodas4P(), Rodas4P2(), Rodas5(),
                           Rodas5P(), Rodas5Pe(), Rodas5Pr(), Rodas6P()]
-    
+
     @testset "Rosenbrock Solver Allocation Analysis" begin
         for solver in rosenbrock_solvers
             @testset "$(typeof(solver)) allocation check" begin
                 integrator = init(linear_prob, solver, dt=0.1, save_everystep=false, abstol=1e-6, reltol=1e-6)
                 step!(integrator)  # Setup step may allocate
-                
+
                 # Use AllocCheck for accurate allocation detection
                 allocs = check_allocs(step!, (typeof(integrator),))
-                
+
                 # These solvers should be allocation-free, but mark as broken for now
                 # to verify with AllocCheck (more accurate than @allocated)
                 @test_broken length(allocs) == 0
-                
+
+                # However, we don't want to allow any dynamic dispatch from this module
+                @test count(
+                    t -> t isa AllocCheck.DynamicDispatch &&
+                        any(s -> contains(string(s.file), "Rosenbrock"), t.backtrace),
+                    allocs
+                ) == 0
+
                 if length(allocs) > 0
                     println("AllocCheck found $(length(allocs)) allocation sites in $(typeof(solver)) step!:")
                     for (i, alloc) in enumerate(allocs[1:min(3, end)])  # Show first 3