The initial_autocorr function calculates the initial guesses for Bairstow’s method for finding
roots of a polynomial, specifically for the auto-correlation function.
The pbairstow_autocorr function implements the simultaneous Bairstow’s method for finding roots of
a polynomial, specifically for the auto-correlation function.
The pbairstow_autocorr_mt function is a multi-threaded implementation of Bairstow’s method for
finding roots of a polynomial, specifically for auto-correlation functions.