Untitled

#a = si02_formula(0.21, 0.5, 0.05)
#next(a), next(a), next(a)
import math
import numpy as np

ref_idx = lambda i : math.sqrt((0.6961663* i * i/(i * i -0.0684043**2))+(0.4079426* i * i/(i * i -0.1162414**2))+(0.8974794*i * i/(i*i-9.896161**2)) + 1.0)
def si02_your(a, b, step):
    return ((i, ref_idx(i)) for i in np.arange(a, b, step))