MPFR Java Bindings
GNU MPFR is a C library for performing mathematical computations on extended precision IEEE 754 binary floating point numbers. Currently, however, MPFR has no Java interface, third-party or otherwise, and all the existing arbitrary precision floating point libraries for Java are not suitable for the task of providing conformance with the IEEE 754-2008 standard for binary floating point numbers. To address this gap, the MPFR Java project exists, with the intent of providing a managed code interface between MPFR and Java analogous to the behavior of Java's existing BigDecimal type, but prioritized to conform to the IEEE standard.
Getting started
To compile for your platform, download the project and run mvn install. The resulting Java code will be placed in the file target/mpfr_java-1.0.jar, and the resulting native code will be placed in the file target/mpfr_java-1.0-<platform>.jar. For example, for 64 bit linux the native code will be found in target/mpfr_java-1.0-linux64.jar. All you need to do in order to use the library is place both of these JARs in the classpath of your project, and then reference the BigFloat class. If you wish to view javadocs for the project, you can run mvn site, which will generate the javadoc html in the directory target/site/apidocs.
Github releases for Windows, Linux, and Mac OS X will come soon.
Building a JNI library which statically links against MPFR and GMP
By default, MFPR Java builds the native libraries using dynamic linking. As a result of this, the default installation will not work correctly, and will create an UnsatisfiedLinkError, if run on a system which does not have MPFR and GMP installed. To work around this problem, the releases we provide statically link these two dependencies. If you wish to do the same on another platform, follow the following instructions:
- Download the latest versions of GMP and MPFR from the web, and unzip their source.
- in the gmp directory, run
./configure --with-pic --build=<arch>; make - in the mpfr directory, run
./configure --with-gmp-include=<gmpdir> --with-gmp-lib=<gmpdir>/.libs --with-pic --build=<arch>; make - in the mpfr-java directory, run
mvn install -Dmpfr.cppflags='-I<mpfrdir>/src -I<gmpdir>' -Dmpfr.libs='<mpfrdir>/src/.libs/libmpfr.a <gmpdir>/.libs/libgmp.a' -Dmpfr.build=<arch>
Where <arch> is the architecture and OS of system you wish to support (e.g. "x86_64-linux").
This will create a jar containing a shared library which is linked statically against mpfr and gmp, and linked dynamically against all other dependencies. Note that this creates a GMP build which does not take advantage of any processor-specific extensions. If you wish to build MPFR Java for absolute maximum performance, you should dynamically link against a version of GMP and MPFR tuned to the specific processor you wish to run on.
Feedback
If you have issues or questions regarding the project, please create an issue in our issue tracker. Pull requests are also welcome as long as they conform to the design principles of the project.