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GMP Functions

Introducere

These functions allow you to work with arbitrary-length integers using the GNU MP library.

These functions have been added in PHP 4.0.4.

Notă: Most GMP functions accept GMP number arguments, defined as resource below. 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 the gmp_init() function.

Avertizare

If you want to explicitly specify a large integer, specify it as a string. If you don't do that, PHP will interpret the integer-literal first, possibly resulting in loss of precision, even before GMP comes into play.

Notă: This extension is available on Windows platforms since PHP 5.1.0.

Necesităţi

You can download the GMP library from » https://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.

Instalarea

In order to have these functions available, you must compile PHP with GMP support by using the --with-gmp option.

Configuraţia la rulare

Această extensie nu are directive de configurare definite în php.ini.

Tipurile resurselor

Most GPM functions operate on or return GMP number resources.

Constante predefinite

Constantele de mai jos sunt definite de această extensie şi vor fi disponibile doar dacă această extensie a fost compilată în interiorul PHP, sau a fost încărcată dinamic în timpul rulării.

GMP_ROUND_ZERO (integer)
GMP_ROUND_PLUSINF (integer)
GMP_ROUND_MINUSINF (integer)
GMP_VERSION (string)
The GMP library version

Exemple

Example#1 Factorial function using GMP

<?php
function fact($x
{
    
$return 1;
    for (
$i=2$i $x$i++) {
        
$return gmp_mul($return$i);
    }
    return 
$return;
}

echo 
gmp_strval(fact(1000)) . "\n";
?>

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

Vedeţi de asemenea

More mathematical functions can be found in the sections BCMath Arbitrary Precision Mathematics Functions and Mathematical Functions.

Cuprins