Fast sqrt in Java at the expense of accuracy

java performance math sqrt
Paresh picture Paresh · Nov 7, 2012 · Viewed 11k times · Source

I am looking for a fast square root implementation in Java for double values in the input range of [0, 2*10^12]. For any value in this range, the precision should be upto 5 decimal places. In other words, the result can differ from the Math.sqrt() method after 5 decimal places. However, this method needs to be much faster than Math.sqrt().

Any ideas? Thanks!

Answer

Martin Thurau picture Martin Thurau · Nov 7, 2012

I don't believe (without a benchmark to prove this wrong) that a pure Java implementation could me much faster than Math.sqrt(). Both the Oracle JRE implementation and the OpenJDK implementation are native implementations.

Related questions

Performance of Java matrix math libraries?

We are computing something whose runtime is bound by matrix operations. (Some details below if interested.) This experience prompted the following question: Do folk have experience with the performance of Java libraries for matrix math (e.g., multiply, inverse, etc.)? …

Read More
Quickly square a double

I am looking for the fastest way to square a double (double d). So far I came up with two approaches: 1. d*d 2. Math.pow(d, 2) To test the performance I set up three test cases, in each I generate …

Read More
Java Math.min/max performance

EDIT: maaartinus gave the answer I was looking for and tmyklebu's data on the problem helped a lot, so thanks both! :) I've read a bit about how HotSpot has some "intrinsics" that injects in the code, specially for Java standard …

Read More