quantize.py

def quantize(w, x, y, z, n) :
    if z == None :
        z = 1.0 - w - x - y
    n = int(n)

    v = [w, x, y, z]
    vn = [a * n for a in v]
    vni = [int(a) for a in vn]
    vnf = [a - ai for a, ai in zip(vn, vni)]

    cutoff = sum(vnf) / 4

    def cround(xi, xf) :
        return float(xi + (0 if xf < cutoff else 1)) / n

    return [cround(ai, af) for ai, af in zip(vni, vnf)]