Find out which solver was used in automatic solver selection

General Usage
1

In julia, I am using an automatic solver selection to solve differential equations using the DifferentialEquations package. I would like to know which solver was used in the end, but when I run sol.alg, I get

CompositeAlgorithm(; algs = (Tsit5{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}(OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!, static(false)), Vern7{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}(OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!, static(false), true), Rosenbrock23{1, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}(nothing, OrdinaryDiffEqCore.DEFAULT_PRECS, OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!), Rodas5P{1, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}(nothing, OrdinaryDiffEqCore.DEFAULT_PRECS, OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!), FBDF{5, 1, false, Nothing, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}(Val{5}(), nothing, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}(1//100, 10, 1//5, 1//5, false, true, 0//1), OrdinaryDiffEqCore.DEFAULT_PRECS, nothing, nothing, :linear, :Standard, OrdinaryDiffEqCore.trivial_limiter!), FBDF{5, 1, false, KrylovJL{typeof(Krylov.gmres!), Int64, Nothing, Tuple{}, Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}}, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}(Val{5}(), KrylovJL{typeof(Krylov.gmres!), Int64, Nothing, Tuple{}, Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}}(Krylov.gmres!, 0, 0, nothing, (), Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}()), NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}(1//100, 10, 1//5, 1//5, false, true, 0//1), OrdinaryDiffEqCore.DEFAULT_PRECS, nothing, nothing, :linear, :Standard, OrdinaryDiffEqCore.trivial_limiter!)), choice_function = OrdinaryDiffEqCore.AutoSwitchCache{Tuple{Tsit5{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}, Vern7{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}}, Tuple{Rosenbrock23{0, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}, Rodas5P{0, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}, FBDF{5, 0, false, Nothing, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}, FBDF{5, 0, false, KrylovJL{typeof(Krylov.gmres!), Int64, Nothing, Tuple{}, Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}}, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}}, Rational{Int64}, Int64}(5, 0, (Tsit5{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}(OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!, static(false)), Vern7{typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!), Static.False}(OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!, static(false), true)), (Rosenbrock23{0, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}(nothing, OrdinaryDiffEqCore.DEFAULT_PRECS, OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!), Rodas5P{0, false, Nothing, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!), typeof(OrdinaryDiffEqCore.trivial_limiter!)}(nothing, OrdinaryDiffEqCore.DEFAULT_PRECS, OrdinaryDiffEqCore.trivial_limiter!, OrdinaryDiffEqCore.trivial_limiter!), FBDF{5, 0, false, Nothing, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}(Val{5}(), nothing, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}(1//100, 10, 1//5, 1//5, false, true, 0//1), OrdinaryDiffEqCore.DEFAULT_PRECS, nothing, nothing, :linear, :Standard, OrdinaryDiffEqCore.trivial_limiter!), FBDF{5, 0, false, KrylovJL{typeof(Krylov.gmres!), Int64, Nothing, Tuple{}, Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}}, NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}, typeof(OrdinaryDiffEqCore.DEFAULT_PRECS), Val{:forward}, true, nothing, Nothing, Nothing, typeof(OrdinaryDiffEqCore.trivial_limiter!)}(Val{5}(), KrylovJL{typeof(Krylov.gmres!), Int64, Nothing, Tuple{}, Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}}(Krylov.gmres!, 0, 0, nothing, (), Base.Pairs{Symbol, Union{}, Tuple{}, @NamedTuple{}}()), NLNewton{Rational{Int64}, Rational{Int64}, Rational{Int64}, Rational{Int64}}(1//100, 10, 1//5, 1//5, false, true, 0//1), OrdinaryDiffEqCore.DEFAULT_PRECS, nothing, nothing, :linear, :Standard, OrdinaryDiffEqCore.trivial_limiter!)), true, 10, 3, 9//10, 9//10, 2, false, 5, 5),)

is there any way of knowing which solver was picked by julia?

2

Not sure.sol.stats ?

4

I only get statistics about the number of function evaluations and Jacobian creations:

SciMLBase.DEStats
Number of function 1 evaluations:                  13773
Number of function 2 evaluations:                  0
Number of W matrix evaluations:                    1455
Number of linear solves:                           9516
Number of Jacobians created:                       13
Number of nonlinear solver iterations:             9396
Number of nonlinear solver convergence failures:   0
Number of fixed-point solver iterations:                     0
Number of fixed-point solver convergence failures:           0
Number of rootfind condition calls:                1945
Number of accepted steps:                          1945
Number of rejected steps:                          205
5

sol.alg_choice, where the integer is the sol.alg.algs[i]

1 Like
6

To be very clear, is the following correct?

sol.alg_choice gives a vector of integers whose length is the number of saved time steps in sol.t. Each integer corresponds to the index of the algorithm in sol.alg.algs that was used for the corresponding time step.

7

Yes