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1996-09-27 06:29:02 -04:00
GNU MP is a library for arbitrary precision arithmetic, operating on
signed integers and rational numbers. It has a rich set of functions,
and the functions have a regular interface.
I have tried to make these functions as fast as possible, both for small
operands and for huge operands. The speed is achieved by using fullwords
as the basic arithmetic type, by using fast algorithms, by defining inline
assembler for mixed sized multiplication and division (i.e 32*32->64 bit
multiplication and 64/32->32,32 bit division), and by hacking the code
with emphasis on speed (and not simplicity and elegance).
The speed of GNU MP is about 5 to 100 times that of Berkeley MP for
small operands. The speed-up increases with the operand sizes for
certain operations, for which GNU MP has asymptotically faster algorithms.
There are four classes of functions in GNU MP.
1. Signed integer arithmetic functions, mpz_*. The set of functions are
intended to be easy to use, being rich and regular.
To use these functions, include the file "gmp.h".
2. Rational arithmetic functions, mpq_*. For now, just a small set of
functions necessary for basic rational arithmetics.
To use these functions, include the file "gmp.h".
3. Positive-integer, low-level, harder-to-use, but for small operands
about twice as fast than the mpz_* functions are the functions in the
mpn_* class. No memory management is performed. The caller must
ensure enough space is available for the results. The set of
functions is not quite regular, nor is the calling interface. These
functions accept input arguments in the form of pairs consisting of a
pointer to the least significant word, and a integral size telling how
many limbs (= words) the pointer points to.
Almost all calculations, in the entire package, are made in these
low-level functions.
These functions are not fully documented in this release. They will
probably be so in a future release.
4. Berkeley MP compatible functions.
To use these functions, include the file "mp.h". You can test if you
are using the GNU version by testing if the symbol __GNU_MP__ is
If you find a bug in the library, please make sure to tell us about it!
You can report bugs, and propose modifications and enhancements to How to report a bug is further described in
the texinfo documentation, see the file gmp.texi.