CODEWITHSUNDEEP
pythonscipydefaultode
Peter B
Peter B

Reputation: 493

How to find the default atol and rtol for scipy.integrate.ode?

How do I find the default parameters in scipy.integrate.ode? Specifically, atol and rtol in integrator dopri5? Parameters can be set with the set_integrator method, but I can’t see any way to query it find out what it’s been using if I do not set them.

Upvotes: 2

Views: 2050

Answers (2)

flutefreak7
flutefreak7

Reputation: 2471

Looking at the source for ode() it looks like the integrator of an ode that you have instantiated can be inspected by doing the following for example:

r = ode(f)
print('atol:', r._integrator.atol)
print('rtol:', r._integrator.rtol)

Upvotes: 4

Wrzlprmft
Wrzlprmft

Reputation: 4415

As far as I can tell, the only way to find out is looking into the source. There, starting with lines 966 (as of now), you’ll find:

class dopri5(IntegratorBase):

    […]

    def __init__(self,
                 rtol=1e-6, atol=1e-12,
                 nsteps=500,
                 max_step=0.0,
                 […]
                 ):

So, dopri’s default absolute tolerance is 10⁻¹² and its default relative tolerance is 10⁻⁶. (Yes, this should be documented.)

Upvotes: 4

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