JVM Arbitrary Precision Libraries

Question

I'm working on a project ( in Scala ), where I have a need to manipulate some very large numbers; far too big to be represented by the integral types. Java provides the BigInteger and BigDecimal classes (and scala provides a nice thin wrapper around them). However, I noticed that these libraries are substantially slower than other arbitrary precision libraries that I've used in the past (i.e. http://www.ginac.de/CLN/), and the speed difference seems larger than what can be attributed to the language alone.

I did some profiling of my program, and 44% of the execution time is being spent in the BigInteger multiply method. I'd like to speed up my program a bit, so I'm looking for a faster and more efficient option than the BigInteger class (and its Scala wrapper). I've looked at LargeInteger ( from JScience) and Aint (from Afloat). However, both seem to perform more slowly than the standard BigInteger class.

Does anyone know of a Java (or available on the JVM) arbitrary precision math library with a focus on high performance integer multiplication and addition?

Answer 1

I'm a bit late...well I only know the apfloat library, available in both C++ and Java. Apfloat-Library:

Answer 2

Unfortunately, I think you are out of luck for a Java native library. I have not found one. I recommend wrapping GMP, which has excellent arbitrary precision performance, using JNI. There is JNI overhead, but if you're in the 1500 digit range, that should be small compared to the difference in algorithmic complexity. You can find various wrappings of GMP for Java (I believe the most popular one is here).