# ROBER Work-Precision Diagrams

##### Chris Rackauckas
using OrdinaryDiffEq, DiffEqDevTools, Sundials, ParameterizedFunctions, Plots, ODE, ODEInterfaceDiffEq, LSODA
gr()
using LinearAlgebra

rober = @ode_def begin
dy₁ = -k₁*y₁+k₃*y₂*y₃
dy₂ =  k₁*y₁-k₂*y₂^2-k₃*y₂*y₃
dy₃ =  k₂*y₂^2
end k₁ k₂ k₃
prob = ODEProblem(rober,[1.0,0.0,0.0],(0.0,1e5),(0.04,3e7,1e4))
sol = solve(prob,CVODE_BDF(),abstol=1/10^14,reltol=1/10^14)
test_sol = TestSolution(sol)
abstols = 1.0 ./ 10.0 .^ (4:11)

8-element Array{Float64,1}:
0.0001
1.0e-5
1.0e-6
1.0e-7
1.0e-8
1.0e-9
1.0e-10
1.0e-11

plot(sol,labels=["y1","y2","y3"])


## Omissions And Tweaking

The following were omitted from the tests due to convergence failures. ODE.jl's adaptivity is not able to stabilize its algorithms, while GeometricIntegratorsDiffEq has not upgraded to Julia 1.0. GeometricIntegrators.jl's methods used to be either fail to converge at comparable dts (or on some computers errors due to type conversions).

#sol = solve(prob,ode23s()); println("Total ODE.jl steps: \$(length(sol))")
#using GeometricIntegratorsDiffEq
#try
#catch e
#    println(e)
#end


ARKODE needs a lower nonlinear_convergence_coefficient in order to not diverge.

#sol = solve(prob,ARKODE(nonlinear_convergence_coefficient = 1e-6),abstol=1e-5,reltol=1e-1); # Noisy, output omitted

sol = solve(prob,ARKODE(nonlinear_convergence_coefficient = 1e-7),abstol=1e-5,reltol=1e-1);


Note that 1e-7 matches the value from the Sundials manual which was required for their example to converge on this problem. The default is 1e-1.

#sol = solve(prob,ARKODE(order=3),abstol=1e-4,reltol=1e-1); # Fails to diverge but doesn't finish

#sol = solve(prob,ARKODE(order=5),abstol=1e-4,reltol=1e-1); # Noisy, output omitted

#sol = solve(prob,ARKODE(order=5,nonlinear_convergence_coefficient = 1e-9),abstol=1e-5,reltol=1e-1); # Noisy, output omitted


## High Tolerances

This is the speed when you just want the answer. ode23s from ODE.jl was removed since it fails. Note that at high tolerances Sundials' CVODE_BDF fails as well so it's excluded from this test.

solve(prob, ddebdf())
solve(prob, rodas())
abstols = 1.0 ./ 10.0 .^ (5:8)
reltols = 1.0 ./ 10.0 .^ (1:4);
setups = [Dict(:alg=>Rosenbrock23()),
Dict(:alg=>Rodas3()),
Dict(:alg=>TRBDF2()),
Dict(:alg=>rodas()),
#Dict(:alg=>lsoda()),
#Dict(:alg=>ROCK2())    #Unstable
#Dict(:alg=>ROCK3())    #needs more iterations
]
gr()
wp = WorkPrecisionSet(prob,abstols,reltols,setups;
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)

setups = [Dict(:alg=>Rosenbrock23()),
Dict(:alg=>Kvaerno3()),
Dict(:alg=>KenCarp4()),
Dict(:alg=>TRBDF2()),
Dict(:alg=>KenCarp3()),
# Dict(:alg=>SDIRK2()), # Removed because it's bad
names = ["Rosenbrock23" "Kvaerno3" "KenCarp4" "TRBDF2" "KenCarp3" "radau"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;names=names,
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)

setups = [Dict(:alg=>Rosenbrock23()),
Dict(:alg=>KenCarp5()),
Dict(:alg=>KenCarp4()),
Dict(:alg=>KenCarp3()),
Dict(:alg=>ARKODE(nonlinear_convergence_coefficient = 1e-9,order=5)),
Dict(:alg=>ARKODE(nonlinear_convergence_coefficient = 1e-8)),
Dict(:alg=>ARKODE(nonlinear_convergence_coefficient = 1e-7,order=3))
]
names = ["Rosenbrock23" "KenCarp5" "KenCarp4" "KenCarp3" "ARKODE5" "ARKODE4" "ARKODE3"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;
names=names,
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)


### Timeseries Errors

abstols = 1.0 ./ 10.0 .^ (5:8)
reltols = 1.0 ./ 10.0 .^ (1:4);
setups = [Dict(:alg=>Rosenbrock23()),
Dict(:alg=>Rodas3()),
Dict(:alg=>TRBDF2()),
Dict(:alg=>rodas()),
#Dict(:alg=>lsoda()),
#Dict(:alg=>ROCK2())    #needs more iterations
#Dict(:alg=>ROCK3())    #needs more iterations
wp = WorkPrecisionSet(prob,abstols,reltols,setups;
appxsol=test_sol,maxiters=Int(1e5),error_estimate=:l2,numruns=10)
plot(wp)

setups = [Dict(:alg=>Rosenbrock23()),
Dict(:alg=>Kvaerno3()),
Dict(:alg=>KenCarp4()),
Dict(:alg=>TRBDF2()),
Dict(:alg=>KenCarp3()),
# Dict(:alg=>SDIRK2()), # Removed because it's bad
names = ["Rosenbrock23" "Kvaerno3" "KenCarp4" "TRBDF2" "KenCarp3" "radau"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;names=names,
appxsol=test_sol,maxiters=Int(1e5),error_estimate=:l2,numruns=10)
plot(wp)


### Low Tolerances

This is the speed at lower tolerances, measuring what's good when accuracy is needed.

abstols = 1.0 ./ 10.0 .^ (7:12)
reltols = 1.0 ./ 10.0 .^ (4:9)

setups = [Dict(:alg=>Rodas5()),
Dict(:alg=>Rodas4P()),
Dict(:alg=>CVODE_BDF()),
Dict(:alg=>ddebdf()),
Dict(:alg=>Rodas4()),
Dict(:alg=>rodas()),
#Dict(:alg=>lsoda()),

]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)

setups = [Dict(:alg=>Rodas4P()),
Dict(:alg=>Kvaerno4()),
Dict(:alg=>Kvaerno5()),
Dict(:alg=>CVODE_BDF()),
Dict(:alg=>KenCarp4()),
Dict(:alg=>KenCarp5()),
Dict(:alg=>Rodas4()),
names = ["Rodas4p" "Kvaerno4" "Kvaerno5" "CVODE_BDF" "KenCarp4" "KenCarp5" "Rodas4" "radau"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;names=names,
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)

setups = [Dict(:alg=>Rodas3()),
Dict(:alg=>Hairer4()),
Dict(:alg=>Hairer42()),
Dict(:alg=>CVODE_BDF()),
Dict(:alg=>Cash4()),
Dict(:alg=>Rodas4()),
names = ["Rodas3" "Hairer4" "Hairer42" "CVODE_BDF" "Cash4" "Rodas4" "radau"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;names=names,
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)


Rodas5 requires much lower tolerances to be stable here. Even then, it does not outdo Rodas4.

abstols = 1.0 ./ 10.0 .^ (10:12)
reltols = 1.0 ./ 10.0 .^ (7:9)

setups = [Dict(:alg=>Rodas4())
Dict(:alg=>Rodas5())]
names = ["Rodas4" "Rodas5"]
wp = WorkPrecisionSet(prob,abstols,reltols,setups;names=names,
save_everystep=false,appxsol=test_sol,maxiters=Int(1e5),numruns=10)
plot(wp)


### Conclusion

At high tolerances, Rosenbrock23 and lsoda hit the the error estimates and are fast. At lower tolerances and normal user tolerances, Rodas4 and Rodas5 are extremely fast. lsoda does quite well across both ends. When you get down to reltol=1e-9 radau begins to become as efficient as Rodas4, and it continues to do well below that.

using DiffEqBenchmarks
DiffEqBenchmarks.bench_footer(WEAVE_ARGS[:folder],WEAVE_ARGS[:file])


## Appendix

These benchmarks are a part of the DiffEqBenchmarks.jl repository, found at: https://github.com/JuliaDiffEq/DiffEqBenchmarks.jl

To locally run this tutorial, do the following commands:

using DiffEqBenchmarks
DiffEqBenchmarks.weave_file("StiffODE","ROBER.jmd")

Computer Information:

Julia Version 1.1.0
Commit 80516ca202 (2019-01-21 21:24 UTC)
Platform Info:
OS: Linux (x86_64-pc-linux-gnu)
CPU: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-6.0.1 (ORCJIT, haswell)


Package Information:

Status: /home/crackauckas/.julia/environments/v1.1/Project.toml
[c52e3926-4ff0-5f6e-af25-54175e0327b1] Atom 0.8.7
[bcd4f6db-9728-5f36-b5f7-82caef46ccdb] DelayDiffEq 5.4.1
[bb2cbb15-79fc-5d1e-9bf1-8ae49c7c1650] DiffEqBenchmarks 0.1.0
[459566f4-90b8-5000-8ac3-15dfb0a30def] DiffEqCallbacks 2.5.2
[f3b72e0c-5b89-59e1-b016-84e28bfd966d] DiffEqDevTools 2.8.0
[aae7a2af-3d4f-5e19-a356-7da93b79d9d0] DiffEqFlux 0.5.0
[78ddff82-25fc-5f2b-89aa-309469cbf16f] DiffEqMonteCarlo 0.15.1
[77a26b50-5914-5dd7-bc55-306e6241c503] DiffEqNoiseProcess 3.3.1
[055956cb-9e8b-5191-98cc-73ae4a59e68a] DiffEqPhysics 3.1.0
[a077e3f3-b75c-5d7f-a0c6-6bc4c8ec64a9] DiffEqProblemLibrary 4.1.0
[0c46a032-eb83-5123-abaf-570d42b7fbaa] DifferentialEquations 6.4.0
[b305315f-e792-5b7a-8f41-49f472929428] Elliptic 0.5.0
[7f56f5a3-f504-529b-bc02-0b1fe5e64312] LSODA 0.4.0
[c030b06c-0b6d-57c2-b091-7029874bd033] ODE 2.4.0
[54ca160b-1b9f-5127-a996-1867f4bc2a2c] ODEInterface 0.4.5
[09606e27-ecf5-54fc-bb29-004bd9f985bf] ODEInterfaceDiffEq 3.3.1
[1dea7af3-3e70-54e6-95c3-0bf5283fa5ed] OrdinaryDiffEq 5.8.1
[2dcacdae-9679-587a-88bb-8b444fb7085b] ParallelDataTransfer 0.5.0
[65888b18-ceab-5e60-b2b9-181511a3b968] ParameterizedFunctions 4.1.1
[91a5bcdd-55d7-5caf-9e0b-520d859cae80] Plots 0.25.2
[d330b81b-6aea-500a-939a-2ce795aea3ee] PyPlot 2.8.1
[731186ca-8d62-57ce-b412-fbd966d074cd] RecursiveArrayTools 0.20.0
[e88e6eb3-aa80-5325-afca-941959d7151f] Zygote 0.3.2