Add GTPSA extension

Project.toml

@@ -41,6 +41,7 @@ ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 GeneralizedGenerated = "6b9d7cbe-bcb9-11e9-073f-15a7a543e2eb"
+GTPSA = "b27dd330-f138-47c5-815b-40db9dd9b6e8"
 MPI = "da04e1cc-30fd-572f-bb4f-1f8673147195"
 Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
 MonteCarloMeasurements = "0987c9cc-fe09-11e8-30f0-b96dd679fdca"
@@ -55,6 +56,7 @@ DiffEqBaseChainRulesCoreExt = "ChainRulesCore"
 DiffEqBaseDistributionsExt = "Distributions"
 DiffEqBaseEnzymeExt = ["ChainRulesCore", "Enzyme"]
 DiffEqBaseGeneralizedGeneratedExt = "GeneralizedGenerated"
+DiffEqBaseGTPSAExt = "GTPSA"
 DiffEqBaseMPIExt = "MPI"
 DiffEqBaseMeasurementsExt = "Measurements"
 DiffEqBaseMonteCarloMeasurementsExt = "MonteCarloMeasurements"
@@ -81,6 +83,7 @@ ForwardDiff = "0.10"
 FunctionWrappers = "1.0"
 FunctionWrappersWrappers = "0.1"
 GeneralizedGenerated = "0.3"
+GTPSA = "1.3"
 LinearAlgebra = "1.9"
 Logging = "1.9"
 MPI = "0.20"

ext/DiffEqBaseGTPSAExt.jl

@@ -0,0 +1,17 @@
+module DiffEqBaseGTPSAExt
+
+if isdefined(Base, :get_extension)
+    using DiffEqBase
+    import DiffEqBase: value
+    using GTPSA
+else
+    using ..DiffEqBase
+    import ..DiffEqBase: value
+    using ..GTPSA
+end
+
+value(x::TPS) = scalar(x);
+value(::Type{TPS{T}}) where {T} = T
+
+
+end

test/downstream/Project.toml

@@ -5,6 +5,7 @@ DiffEqBase = "2b5f629d-d688-5b77-993f-72d75c75574e"
 DiffEqCallbacks = "459566f4-90b8-5000-8ac3-15dfb0a30def"
 Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+GTPSA = "b27dd330-f138-47c5-815b-40db9dd9b6e8"
 Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
 ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
 MultiScaleArrays = "f9640e96-87f6-5992-9c3b-0743c6a49ffa"

test/downstream/gtpsa.jl

@@ -0,0 +1,39 @@
+using OrdinaryDiffEq, ForwardDiff, GTPSA, Test
+
+f!(du, u, p, t) = du .= p .* u
+
+# Initial variables and parameters
+x = [1.0, 2.0, 3.0]
+p = [4.0, 5.0, 6.0]
+
+prob = ODEProblem(f!, x, (0.0, 1.0), p)
+sol = solve(prob, Tsit5(), reltol=1e-16, abstol=1e-16)
+
+# Parametric GTPSA map
+desc = Descriptor(3, 2, 3, 2) # 3 variables 3 parameters, both to 2nd order
+dx = vars(desc)
+dp = params(desc)
+prob_GTPSA = ODEProblem(f!, x .+ dx, (0.0, 1.0), p .+ dp)
+sol_GTPSA = solve(prob_GTPSA, Tsit5(), reltol=1e-16, abstol=1e-16)
+
+@test sol.u[end] ≈ scalar.(sol_GTPSA.u[end]) # scalar gets 0th order part
+
+# Compare Jacobian against ForwardDiff
+J_FD = ForwardDiff.jacobian([x..., p...]) do t
+    prob = ODEProblem(f!, t[1:3], (0.0, 1.0), t[4:6])
+    sol = solve(prob, Tsit5(), reltol=1e-16, abstol=1e-16)
+    sol.u[end]
+end
+
+@test J_FD ≈ GTPSA.jacobian(sol_GTPSA.u[end], include_params=true)
+
+# Compare Hessians against ForwardDiff
+for i in 1:3
+    Hi_FD = ForwardDiff.hessian([x..., p...]) do t
+        prob = ODEProblem(f!, t[1:3], (0.0, 1.0), t[4:6])
+        sol = solve(prob, Tsit5(), reltol=1e-16, abstol=1e-16)
+        sol.u[end][i]
+    end
+    @test Hi_FD ≈ GTPSA.hessian(sol_GTPSA.u[end][i], include_params=true)
+end
+

test/runtests.jl

@@ -55,6 +55,7 @@ end
         @time @safetestset "Default linsolve with structure" include("downstream/default_linsolve_structure.jl")
         @time @safetestset "Callback Merging Tests" include("downstream/callback_merging.jl")
         @time @safetestset "LabelledArrays Tests" include("downstream/labelledarrays.jl")
+        @time @safetestset "GTPSA Tests" include("downstream/gtpsa.jl")
     end
 
     if !is_APPVEYOR && GROUP == "Downstream2"