PyODEPack

Fast python wrappers for ODE solvers written in C++

Available Solvers

• LSODA
• Verner 6(5) (efficient)
• Bogacki-Shampine (RK23)
• Verner 9(8) (efficient)
• RadauIIA-5
• LOVERO competitor to LSODE (nonstiff)

Requirements

• setuptools
• numpy
• scipy (needed to load LAPACK routines at runtime)

Install

SYSTEM_VERSION_COMPAT=1 python -m pip install git+https://github.com/vlovero/PyODEPack.git The SYSTEM_VERSION_COMPAT environment variable is to fix the MacOS issue that causes clang to not like the march=native compiler flag.

Example Usage

>>> import numpy as np
>>> from pyodepack import solveIVP, methods
>>> from pprint import pprint
>>>
>>> def f(t, z):
...     return np.array([z[1], -z[0]])
...
>>> 
>>> def g(t, z, out, args):
...     k1, k2 = args
...     out[0] = -k1**2 * z[0]
...     out[1] = -k2**2 * z[1]
...
>>> y, _, info = solveIVP(f, [0, 1], [0, 20], method=methods.RKV65E, full_output=True)
>>>
>>> pprint(info)
{'fails': 0,
'feval': 683,
'hout': 0.4224769620224126,
'jeval': 0,
'message': 'success',
'numlu': 0,
'steps': 85}
>>> np.abs(y[:, 0] - np.sin([0, 20]))
array([0.0000000e+00, 3.5364417e-09])
>>> y, _, info = solveIVP(g, [0, 1], [0, 20], args=(1, 20), isvoid=True, full_output=True)
>>>
>>> pprint(info)
{'fails': 0,
'feval': 213,
'hout': 79.76670760332844,
'jeval': 5,
'message': 'success',
'numlu': 0,
'steps': 104}