Inverse square root and fast inverse square root

main.py

# Inverse square root and fast inverse square root
from ctypes import c_long, c_float, addressof, cast, POINTER
def fisr(number: float) -> float:
    y = c_float(number)
    i = c_long(0x5f3759df - (cast(addressof(y), POINTER(c_long)).contents.value >> 1))
    y = cast(addressof(i), POINTER(c_float)).contents.value
    return y * (3 - (number * y * y)) / 2
"""
float fisr(float number) {
    float y = number;
    long i = 0x5f3759df - (*(long*) &y >> 1);
    y = *(float *) &i;
    return y * (3.f - (number * y * y)) / 2.f;
}
"""
def isr(number: float) -> float:
    return 1 / number ** .5