4 GNU MP is a library for arbitrary precision arithmetic, operating on signed
5 integers, rational numbers, and floating point numbers. It has a rich set
6 of functions, and the functions have a regular interface.
8 GNU MP is designed to be as fast as possible, both for small operands and for
9 huge operands. The speed is achieved by using fullwords as the basic
10 arithmetic type, by using fast algorithms, by carefully optimized assembly
11 code for the most common inner loops for a lots of CPUs, and by a general
12 emphasis on speed (instead of simplicity or elegance).
14 The speed of GNU MP is believed to be faster than any other similar library.
15 The advantage for GNU MP increases with the operand sizes for certain
16 operations, since GNU MP in many cases has asymptotically faster algorithms.
21 First, you have to configure and compiler GNU MP. Simply typing
25 will normally do a reasonable job, but will not give optimal library
26 execution speed. So unless you're very unpatient, please read the detailed
27 instructions in the file INSTALL or in gmp.texi.
29 Once you have compiled the library, you should write some small example, and
30 make sure you can compile them. A typical compilation command is this:
32 gcc -g your-file.c -I<gmp-source-dir> <gmp-bin-dir>libgmp.a -lm
34 If you have installed the library, you can simply do:
36 gcc -g your-file.c -lgmp -lm
38 The -lm is normally not needed, since only a few functions in GNU MP use the
41 Here is a sample program that declares 2 variables, initializes them as
42 required, and sets one of them from a signed integer, and the other from a
43 string of digits. It then prints the product of the two numbers in base 10.
52 mpz_init (a); /* initialize variables */
56 mpz_set_si (a, 756839); /* assign variables */
57 mpz_set_str (b, "314159265358979323846", 0);
58 mpz_mul (p, a, b); /* generate product */
59 mpz_out_str (stdout, 10, p); /* print number without newline */
60 puts (""); /* print newline */
62 mpz_clear (a); /* clear out variables */
69 This might look tedious, with all initializing and clearing. Fortunately
70 some of these operations can be combined, and other operations can often be
71 avoided. The example above would be written differently by an experienced
83 mpz_init_set_str (b, "314159265358979323846", 0);
84 mpz_mul_ui (p, b, 756839); /* generate product */
85 mpz_out_str (stdout, 10, p); /* print number without newline */
86 puts (""); /* print newline */
94 There are five classes of functions in GNU MP.
96 1. Signed integer arithmetic functions, mpz_*. These functions are intended
97 to be easy to use, with their regular interface. The associated type is
100 2. Rational arithmetic functions, mpq_*. For now, just a small set of
101 functions necessary for basic rational arithmetics. The associated type
104 3. Floating-point arithmetic functions, mpf_*. If the C type `double'
105 doesn't give enough precision for your application, declare your
106 variables as `mpf_t' instead, set the precision to any number desired,
107 and call the functions in the mpf class for the arithmetic operations.
109 4. Positive-integer, hard-to-use, very low overhead functions are in the
110 mpn_* class. No memory management is performed. The caller must ensure
111 enough space is available for the results. The set of functions is not
112 regular, nor is the calling interface. These functions accept input
113 arguments in the form of pairs consisting of a pointer to the least
114 significant word, and a integral size telling how many limbs (= words)
115 the pointer points to.
117 Almost all calculations, in the entire package, are made by calling these
120 5. Berkeley MP compatible functions.
122 To use these functions, include the file "mp.h". You can test if you are
123 using the GNU version by testing if the symbol __GNU_MP__ is defined.
125 For more information on how to use GNU MP, please refer to the documentation.
126 It is composed from the file gmp.texi, and can be displayed on the screen or
127 printed. How to do that, as well how to build the library, is described in
128 the INSTALL file in this directory.
133 If you find a bug in the library, please make sure to tell us about it!
135 Report bugs and propose modifications and enhancements to
136 bug-gmp@prep.ai.mit.edu. What information is needed in a good bug report is
137 described in the manual.