import math


def fwhm(coeff):
    """Calculate the Full-Width at Half Maximum

    This function will calculate the FWHM based on the following formula
    fwhm = 2*sigma*sqrt(2*ln(2)).

    Arguments:
    coeff -- coefficients as calculated by SciPy curve_fit
    """
    return abs(2 * coeff[2] * math.sqrt(2 * math.log(2)))