On Mon, 10 Feb 2025 09:17:51 GMT, Per Minborg <pminb...@openjdk.org> wrote:
>> fabioromano1 has updated the pull request incrementally with one additional >> commit since the last revision: >> >> An optimization > > This PR seems to be targeting performance, yet no benchmarks are provided > comparing the current vs. proposed branch with respect to performance. We > need to understand the upside of the proposed changes. @minborg The essential part of the sqrt algorithms is the actual computing of root's digits. In the PR implementation, this task is performed by calling `BigInteger.sqrt()`, while in the current implementation is done by Newton's iteration loop. The existing benchmarks I've done for `BigInteger.sqrt()` already proved that the current code of `BigInteger.sqrt()`, which implements Zimmermann's sqrt algorithm, is way much faster (`O(n^k)`, if the running time for multiply is `O(n^k)`) than the older implementation of `BigInteger.sqrt()` (`O(n^k log n)`), which also used Newton's method. Since the arithmetic operations are more time-consuming for `BigDecimal`s rather than `BigInteger`s, then it's easy to see that, for the same digit precision, Newton's method is much slower when done with `BigDecimal`s, so this should show that the PR implementation is way much faster than the current implementation of `BigDecimal.sqrt()`. ------------- PR Comment: https://git.openjdk.org/jdk/pull/21301#issuecomment-2648901484
