A Double-Double and Quad-Double Arithmetic library.
Double-double and quad-double numbers are unevaluated sum of
two and four IEEE doubles capable of representing 106 and 212 bits
of significand, respectively. The library is written in C++, taking full
advantage of operator overloading. C, Fortran 77, and Fortran 90 interfaces
are also provided.

This work was done at Lawrence Berkeley National Laboratory,
NERSC Division, Yozo Hida with Xiaoye S. Li and David H. Bailey.

Note: This package is an older package, it is not thread-safe. New users should
use DQFUN, QXFUN or DDFUN.