These functions allow you to work with arbitrary-length integers
using the GNU MP library. In order to have these
functions available, you must compile PHP with
GMP support by using the `--with-gmp` option.

You can download the GMP library from http://www.swox.com/gmp/. This site also has the GMP manual available.

You will need GMP version 2 or better to use these functions. Some functions may require more recent version of the GMP library.

These functions have been added in PHP 4.0.4.

Note:Most GMP functions accept GMP number arguments, defined asresourcebelow. However, most of these functions will also accept numeric and string arguments, given that it is possible to convert the latter to a number. Also, if there is a faster function that can operate on integer arguments, it would be used instead of the slower function when the supplied arguments are integers. This is done transparently, so the bottom line is that you can use integers in every function that expects GMP number. See also thegmp_init()function.

This will calculate factiorial of 1000 (pretty big number) very fast.

**Table of Contents**- gmp_init — Create GMP number
- gmp_intval — Convert GMP number to integer
- gmp_strval — Convert GMP number to string
- gmp_add — Add numbers
- gmp_sub — Subtract numbers
- gmp_mul — Multiply numbers
- gmp_div_q — Divide numbers
- gmp_div_r — Remainder of the division of numbers
- gmp_div_qr — Divide numbers and get quotient and remainder
- gmp_div — Divide numbers
- gmp_mod — Modulo operation
- gmp_divexact — Exact division of numbers
- gmp_cmp — Compare numbers
- gmp_neg — Negate number
- gmp_abs — Absolute value
- gmp_sign — Sign of number
- gmp_fact — Factorial
- gmp_sqrt — Square root
- gmp_sqrtrm — Square root with remainder
- gmp_perfect_square — Perfect square check
- gmp_pow — Raise number into power
- gmp_powm — Raise number into power with modulo
- gmp_prob_prime — Check if number is "probably prime"
- gmp_gcd — Calculate GCD
- gmp_gcdext — Calculate GCD and multipliers
- gmp_invert — Inverse by modulo
- gmp_legendre — Legendre symbol
- gmp_jacobi — Jacobi symbol
- gmp_random — Random number
- gmp_and — Logical AND
- gmp_or — Logical OR
- gmp_xor — Logical XOR
- gmp_setbit — Set bit
- gmp_clrbit — Clear bit
- gmp_scan0 — Scan for 0
- gmp_scan1 — Scan for 1
- gmp_popcount — Population count
- gmp_hamdist — Hamming distance