libdivide4j
Optimized integer division for Java
This is a Java fork of C/C++ libdivide library for fast integer division (http://libdivide.com and https://github.com/ridiculousfish/libdivide).
Fast division by constant divisor is about 2-3 times faster then ordinary Java divide operation on most of modern CPUs.
Requirements: Java 8 or higher
Examples
The typical use case is when you have to use divide operation many times with a fixed divisor.
long[] someData = ...;
long denominator = 45;
FastDivision.Magic magic = FastDivision.magicSigned(denominator);
long[] reduced = new long[someData.length];
for (int i = 0; i < someData.length; ++i){
// this is the same as someData[i] / denominator but 3 times faster
reduced[i] = FastDivision.divideSignedFast(someData[i], magic);
}Library supports operations with unsigned integers:
// large unsigned modulus
long largeModulus = Long.MAX_VALUE + 1;
// some large number
long someNum = Long.MAX_VALUE + 99999;
FastDivision.Magic magic = FastDivision.magicUnsigned(denominator);
// this will give 99998 (obviously)
long reduced = FastDivision.modUnsignedFast(someNum, magic);
assert reduced == 99998;Maven
Maven dependency:
<dependency>
<groupId>cc.redberry</groupId>
<artifactId>libdivide4j</artifactId>
<version>1.2</version>
</dependency>