After changing `BigInteger.sqrt()` algorithm, this can be also used to speed up `BigDecimal.sqrt()` implementation. Here is how I made it.
The main steps of the algorithm are as follows: first argument reduce the value to an integer using the following relations: x = y * 10 ^ exp sqrt(x) = sqrt(y) * 10^(exp / 2) if exp is even sqrt(x) = sqrt(y*10) * 10^((exp-1)/2) is exp is odd Then use BigInteger.sqrt() on the reduced value to compute the numerical digits of the desired result. Finally, scale back to the desired exponent range and perform any adjustment to get the preferred scale in the representation. ------------- Commit messages: - Merge branch 'openjdk:master' into patchBigDecimalSqrt - Change BigDecimal.sqrt() implementation Changes: https://git.openjdk.org/jdk/pull/21301/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21301&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8341402 Stats: 302 lines in 2 files changed: 109 ins; 129 del; 64 mod Patch: https://git.openjdk.org/jdk/pull/21301.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21301/head:pull/21301 PR: https://git.openjdk.org/jdk/pull/21301
