On Sat, 26 Apr 2025 16:44:26 GMT, fabioromano1 <[email protected]> wrote:
>> This PR optimizes `BigInteger.pow(int)` method. The primary enhancement in
>> `pow()` is not concerned most on execution time, but rather in memory
>> optimization, because the PR implementation does the "shift of the exponent"
>> squaring the result rather than the base, so the base is not squared like in
>> the current implementation, and this permits to save about half of the
>> memory.
>
> fabioromano1 has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Removed method used by nth-root
src/java.base/share/classes/java/math/BigInteger.java line 2721:
> 2719: if (!pow.equals(ONE)) {
> 2720: for (int i = 0; i < blockLen; i++)
> 2721: pow = pow.multiply(pow);
Majority of the time we have `blockLen == maxExpLen`. We should cache that
pow-to-maxExpLen result too, if we have `maxExpLen >= nLen` initially. Maybe
also calculate power-to-`nLen % maxExpLen` as that will be used in the final
round of the loop.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/24690#discussion_r2061496813
