Chapter 11. Some Elementary Functions
11–1 Integer Square Root
By the “integer square root” function, we mean the function ⌊⌋. To extend its range of application and to avoid deciding what to do with a negative argument, we assume x is unsigned. Thus, 0 ≤ x ≤ 232 – 1.
For floating-point numbers, the square root is almost universally computed by Newton’s method. This method begins by somehow obtaining a starting estimate g0 of . Then, a series of more accurate estimates is obtained from
The iteration converges quadratically—that is, ...