RFR: 8077587: BigInteger Roots [v19]

[Andrew Haley]

On Sun, 20 Apr 2025 16:07:56 GMT, fabioromano1 <duke at openjdk.org> wrote:

>> This PR implements nth root computation for `BigInteger`s using Newton method and optimizes `BigInteger.pow(int)` method.
>> [Here is a proof of convergence of the recurrence used.](https://github.com/user-attachments/files/19785045/nth_root_newton_proof_integers.pdf)
>
> fabioromano1 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Code simplification

src/java.base/share/classes/java/math/MutableBigInteger.java line 2002:

> 2000:             // Don't use conditional-or to ensure to do both divisions
> 2001:             if (rToN.divideOneWord(n, q1) != 0
> 2002:                     | !q1.divide(new MutableBigInteger(rToN1.mag), delta).isZero())

Suggestion:

            // Don't use conditional-or to ensure to do both divisions [because ...]
            if ((rToN.divideOneWord(n, q1) != 0)
                    | (!q1.divide(new MutableBigInteger(rToN1.mag), delta).isZero()))

... add parens for clarity.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24690#discussion_r2052135457