Merge pull request #2753 from SciML/hr/fix_stats_stabilized_rk

fix stats of stabilized RK methods

Author: ChrisRackauckas

lib/OrdinaryDiffEqStabilizedRK/src/rkc_perform_step.jl

@@ -35,6 +35,7 @@ end
         μ, κ = recf[cache.start + (i - 2) * 2 + 1], recf[cache.start + (i - 2) * 2 + 2]
         ν = -1 - κ
         u = f(uᵢ₋₁, p, tᵢ₋₁)
+        OrdinaryDiffEqCore.increment_nf!(integrator.stats, 1)
         tᵢ₋₁ = dt * μ - ν * tᵢ₋₂ - κ * tᵢ₋₃
         u = (dt * μ) * u - ν * uᵢ₋₁ - κ * uᵢ₋₂
         i < cache.mdeg && (uᵢ₋₂ = uᵢ₋₁;
@@ -110,6 +111,7 @@ end
         μ, κ = recf[ccache.start + (i - 2) * 2 + 1], recf[ccache.start + (i - 2) * 2 + 2]
         ν = -1 - κ
         f(k, uᵢ₋₁, p, tᵢ₋₁)
+        OrdinaryDiffEqCore.increment_nf!(integrator.stats, 1)
         tᵢ₋₁ = dt * μ - ν * tᵢ₋₂ - κ * tᵢ₋₃
         @.. broadcast=false u=(dt * μ) * k - ν * uᵢ₋₁ - κ * uᵢ₋₂
         if i < ccache.mdeg
@@ -192,6 +194,7 @@ end
         μ, κ = recf[cache.start + (i - 2) * 2 + 1], recf[cache.start + (i - 2) * 2 + 2]
         ν = -1 - κ
         u = f(uᵢ₋₁, p, tᵢ₋₁)
+        OrdinaryDiffEqCore.increment_nf!(integrator.stats, 1)
         tᵢ₋₁ = dt * μ - ν * tᵢ₋₂ - κ * tᵢ₋₃
         u = (dt * μ) * u - ν * uᵢ₋₁ - κ * uᵢ₋₂
         i < cache.mdeg && (uᵢ₋₂ = uᵢ₋₁;
@@ -314,6 +317,7 @@ end
         μ, κ = recf[ccache.start + (i - 2) * 2 + 1], recf[ccache.start + (i - 2) * 2 + 2]
         ν = -1 - κ
         f(k, uᵢ₋₁, p, tᵢ₋₁)
+        OrdinaryDiffEqCore.increment_nf!(integrator.stats, 1)
         tᵢ₋₁ = (dt * μ) - ν * tᵢ₋₂ - κ * tᵢ₋₃
         @.. broadcast=false u=(dt * μ) * k - ν * uᵢ₋₁ - κ * uᵢ₋₂
         if i < ccache.mdeg

lib/OrdinaryDiffEqStabilizedRK/test/rkc_tests.jl

@@ -72,3 +72,33 @@ end
         @test sim.𝒪est[:l∞]≈5 atol=testTol
     end
 end
+
+@testset "Number of function evaluations" begin
+    x = Ref(0)
+    u0 = [1.0, 1.0]
+    tspan = (0.0, 1.0)
+    probop = ODEProblem(u0, tspan) do u, p, t
+        x[] += 1
+        return -500 * u
+    end
+    probip = ODEProblem(u0, tspan) do du, u, p, t
+        x[] += 1
+        @. du = -500 * u
+        return nothing
+    end
+
+    @testset "$prob" for prob in [probop, probip]
+        eigen_est = (integrator) -> integrator.eigen_est = 500
+        algs = [ROCK2(), ROCK2(eigen_est = eigen_est),
+                ROCK4(), ROCK4(eigen_est = eigen_est),
+                RKC(), RKC(eigen_est = eigen_est),
+                SERK2(), SERK2(eigen_est = eigen_est),
+                ESERK4(), ESERK4(eigen_est = eigen_est),
+                ESERK5(), ESERK5(eigen_est = eigen_est)]
+        @testset "$alg" for alg in algs
+            x[] = 0
+            sol = solve(prob, alg)
+            @test x[] == sol.stats.nf
+        end
+    end
+end