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

Question

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.

Answer 1

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.)