python fast square root
from ctypes import c_float, c_int32, cast, byref, POINTER
def ctypes_isqrt(number):
threehalfs = 1.5
x2 = number * 0.5
y = c_float(number)
i = cast(byref(y), POINTER(c_int32)).contents.value
i = c_int32(0x5f3759df - (i >> 1))
y = cast(byref(i), POINTER(c_float)).contents.value
y = y * (1.5 - (x2 * y * y))
return y