'Which algorithm does Python use for estimating square root value?
I wonder about which algorithm does Python use for estimating square root values ? Is it Newton or Babylonian or other ?
Solution 1:[1]
In CPython, math.sqrt is implemented in terms of C/POSIX sqrt function, so the only answer to give is "whatever C/POSIX does". On systems with an assembly level square root function (e.g. x86's fsqrt) the C runtime may delegate to the chip, in which case you'd need to know the chip details to know how it performs the calculation.
There is an approximate square root and a more complicated algorithm for math.isqrt if you care to look at it. I suspect it doesn't precisely match a textbook method, given optimizations for computers won't match the way humans optimize doing math by hand.
Solution 2:[2]
It depends on the implementation; the language does not define the algorithm. ShadowRanger already hit two common ones. These are general, software-based methods.
However, it's quite common for the processor itself to have a machine-level SQRT function. Intel chips have implemented basic transcendental functions in the late 1980s. As a result, iPython simply in-lines the on-chip function; there is no software algorithm, as the on-chip code determines the value by a couple of hardware operations, deriving mantissa and characteristic in parallel.
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Mark Dickinson |
| Solution 2 | Prune |