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GSL ODE-solvers' status
- From: Tuomo Keskitalo <Tuomo dot Keskitalo at iki dot fi>
- To: GSL Discuss Mailing List <gsl-discuss at sourceware dot org>
- Date: Sun, 22 Oct 2017 13:30:49 +0300
- Subject: GSL ODE-solvers' status
- Authentication-results: sourceware.org; auth=none
Dear all,
Patrick found this recent blog post by Christopher Rackauckas, who is
the developer of DifferentialEquations.jl, which contains a wide
selection of ODE-solvers for Julia:
http://www.stochasticlifestyle.com/comparison-differential-equation-solver-suites-matlab-r-julia-python-c-fortran/
Christopher also has given an informative talk at the Julia Developers
conference:
https://www.juliabloggers.com/video-introduction-to-differentialequations-jl/
I'm happy to see that there has been at least some progress on ODE
solving methods! Unfortunately, I am no longer really up-to-date with
this field. If someone has the opportunity to work on GSL ODE-solvers, I
try to point towards potential places of improvement. The methods
suggested by Cristoph in his presentation are:
On explicit side:
- Bogacki-Shampine 3/2 method
- Tsitouras 5/4 Runge-Kutta method
- Verner 7/6 Runge-Kutta method
On implicit side:
- Rosenbrock 2/3 method
- Radau IIA Runge-Kutta variable order method
- CVODE_BDF. GSL's msbdf is based on this method.
More information on these are surely available in
DifferentialEquations.jl source codes.
Also, for time stepping, there appears to be some PI-controller based
method for adjusting step size, which is very interesting.
Finally, Cristoph does not talk in favor of extrapolation methods, but I
have previously wondered how much better bsimp would fare, if the
internal iteration would be modified so that it continues only up to
user given tolerances, instead of near machine precision.
It would be interesting to see if these (old and) new methods would
yield significant improvements compared to those existing now in
ode-initval2, or would improvements remain marginal?
As for GSL ode-initval2 framework: Room for improvement exists in better
co-operation of GSL stepper and control routines. For multistep methods,
it is not good that method order is adjusted internally by stepper and
step size is adjusted independently by control routines.
Final tip for all ODE-solver users: Benchmark different steppers for
your problem. Depending on the problem and your tolerance requirements,
you may get significant improvements just by changing the stepper.
BR,
Tuomo
--
Tuomo.Keskitalo@iki.fi
http://iki.fi/tuomo.keskitalo