Algorithm in fixmath.Sqrt

[hyamw]

When I try to use fixmath.Sqrt, I found that the difference between returns value and the expected value is much bigger than I expected. So I checked the source code and found the source code is confused me. As I known that in Newton’s Method, the guess value should be: Xn+1=(Xn+V/Xn)/2

but in fixmath, the guess value is: var c = (b + (num.value / b)) >> 1;

I think the fixed point division should be applied here. var c = (b + ((num.value << fixlut.PRECISION)/b)) >> 1;

Sorry if I misunderstood the code

[RomanZhu]

FP has a usable range of approximately -65000 to 65000 Since you can't sqrt on a negative number, then we have a range of 0 to 65000

On that range, the max deviation of the result is 0.01f at the end of the range The deviation is unnoticeably small at the beginning of the range