mpfr:
mpfr: The MPFR library is a C library for multiple-precision floating-point
mpfr: computations with exact rounding (also called correct rounding).
mpfr: It is based on the GMP multiple-precision library.
mpfr: The main goal of MPFR is to provide a library for multiple-precision
mpfr: floating-point computation which is both efficient and has 
mpfr: well-defined semantics. It copies the good ideas from the
mpfr: ANSI/IEEE-754 standard for double-precision floating-point arithmetic
mpfr: (53-bit mantissa).
mpfr: