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tornadox

Lightweight, probabilistic ODE solvers. Fast like the wind. 🌪️ Powered by JAX.

Note!

We don't really work on Tornadox anymore. Instead, we recommend you check out Probdiffeq for JAX code or ProbNumDiffEq.jl for Julia code. These two are more actively maintained and both repositories can do almost everything that Tornadox does (and more!).

That said, if you would like to work with Tornadox specifically and run into issues, feel free to reach out!

Installation

Install tornadox via

pip install tornadox

Or get the most recent version from source:

pip install git+https://github.com/pnkraemer/tornadox.git

Usage

Use tornadox as follows.

import jax.numpy as jnp
from tornadox import ek0, ek1, init, step, ivp

# Create a solver. Any of the following work. 
# The signatures of all solvers coincide.
solver1 = ek0.KroneckerEK0()
solver2 = ek0.ReferenceEK0(num_derivatives=6)
solver3 = ek1.ReferenceEK1(initialization=init.TaylorMode())
solver4 = ek1.DiagonalEK1(initialization=init.RungeKutta())
solver5 = ek1.ReferenceEK1(num_derivatives=5, steprule=step.AdaptiveSteps())

# Solve an IVP
vdp = ivp.vanderpol(t0=0., tmax=1., stiffness_constant=1.0)

for solver in [solver1, solver2, solver3, solver4, solver5]:
    
    # Full solve
    print(solver)
    solver.solve(vdp)
    solver.solve(vdp, stop_at=jnp.array([1.2, 1.3]))
    
    # Only solve for the final state
    solver.simulate_final_state(vdp)
    
    # Or go straight to the generator
    for state, info in solver.solution_generator(vdp):
        pass
    print(info)
    
    print()

Citation

The efficient implementation of ODE filters is explained in the paper (link)


@InProceedings{pmlr-v162-kramer22b,
  title = 	 {Probabilistic {ODE} Solutions in Millions of Dimensions},
  author =       {Kr{\"a}mer, Nicholas and Bosch, Nathanael and Schmidt, Jonathan and Hennig, Philipp},
  booktitle = 	 {Proceedings of the 39th International Conference on Machine Learning},
  pages = 	 {11634--11649},
  year = 	 {2022},
  editor = 	 {Chaudhuri, Kamalika and Jegelka, Stefanie and Song, Le and Szepesvari, Csaba and Niu, Gang and Sabato, Sivan},
  volume = 	 {162},
  series = 	 {Proceedings of Machine Learning Research},
  month = 	 {17--23 Jul},
  publisher =    {PMLR},
  pdf = 	 {https://proceedings.mlr.press/v162/kramer22b/kramer22b.pdf},
  url = 	 {https://proceedings.mlr.press/v162/kramer22b.html}
}

Please consider citing it if you use this repository for your research.