math.sqrt.bsearch.py

def sqrt_binary(num):
    if num > 1:
    low = 1
    high = num
else :
    low = num
    high = 1
    mid = float(low) + float((high - low) / 2)
while abs(mid ** 2 - num) > 0.000001:
    if mid ** 2 < num:
    low = mid
else :
    high = mid
mid = (low + high) / 2
return round(mid, 6)

math.sqrt.magic.c

float q_rsqrt(float number) {
    int i;
    float x2, y;
    const float threehalfs = 1.5;
    x2 = number * 0.5;
    y = number;
    i = * (int * ) & y;
    i = 0x5f3759df - (i >> 1);
    y = * (float * ) & i;
    y = y * (threehalfs - (x2 * y * y));
    y = y * (threehalfs - (x2 * y * y));
    y = y * (threehalfs - (x2 * y * y));

    return 1.0 / y;
}