Is there a scaled complementary error function in python available?

Question

In matlab there is a special function which is not available in any of the collections for the Python I know (numpy, scipy, mpmath, ...).

Probably there are other p

Answer 1

Here is a simple and fast implementation giving 12-13 digit accuracy globally:

from scipy.special import exp, erfc

def erfcx(x):
    if x < 25:
        return erfc(x) * exp(x*x)
    else:
        y = 1. / x
        z = y * y
        s = y*(1.+z*(-0.5+z*(0.75+z*(-1.875+z*(6.5625-29.53125*z)))))
        return s * 0.564189583547756287