Unexpected Behavior In Scipy Isf

I am using scipy's stats module to try and determine values of a distribution at which the upper tail probability reaches some small value, but I am getting some very unrealistic r

Solution 1:

This appears to be a bug in scipy.special.btdtri which is supposed to compute quantiles for the beta distribution. Maybe you can file a bug report.

>>>from scipy import special>>>special.btdtri (betaparams[0],betaparams[1], 1-1e-6)
0.00068501413697504238
>>>special.btdtri (betaparams[0],betaparams[1], 1-1e-7)
0.99999966996999767

I can't figure out where btdtri is defined.

EDIT: For the record, here is the SciPy bug report: https://github.com/scipy/scipy/issues/4677