** THE GNU MP LIBRARY**

GNU MP is a library for arbitrary precision arithmetic, operating on signed

integers, rational numbers, and floating point numbers. It has a rich set of

functions, and the functions have a regular interface.

GNU MP is designed to be as fast as possible, both for small operands and huge

operands. The speed is achieved by using fullwords as the basic arithmetic

type, by using fast algorithms, with carefully optimized assembly code for the

most common inner loops for lots of CPUs, and by a general emphasis on speed

(instead of simplicity or elegance).

GNU MP is believed to be faster than any other similar library. Its advantage

increases with operand sizes for certain operations, since GNU MP in many

cases has asymptotically faster algorithms.

** OVERVIEW OF GNU MP**

There are five classes of functions in GNU MP.

1. Signed integer arithmetic functions (mpz). These functions are intended

to be easy to use, with their regular interface. The associated type is

`mpz_t’.

2. Rational arithmetic functions (mpq). For now, just a small set of

functions necessary for basic rational arithmetics. The associated type

is `mpq_t’.

3. Floating-point arithmetic functions (mpf). If the C type `double’

doesn’t give enough precision for your application, declare your

variables as `mpf_t’ instead, set the precision to any number desired,

and call the functions in the mpf class for the arithmetic operations.

4. Positive-integer, hard-to-use, very low overhead functions are 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

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 an integral size telling how many limbs (= words)

the pointer points to.

Almost all calculations, in the entire package, are made by calling these

low-level functions.

5. 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 defined.

For more information on how to use GNU MP, please refer to the documentation.

It is composed from the file doc/gmp.texi, and can be displayed on the screen

or printed. How to do that, as well how to build the library, is described in

the INSTALL file in this directory.

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