PHP  
downloads | documentation | faq | getting help | mailing lists | reporting bugs | php.net sites | links | my php.net 
search for in the  
<textdomaingmp_abs>
view the version of this page
Last updated: Thu, 21 Aug 2003

XXXV. GMP functions

Introduction

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.

Note: 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.

Warning

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.

Note: This extension is not available on Windows platforms.

Requirements

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.

Installation

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

Runtime Configuration

This extension has no configuration directives defined in php.ini.

Resource Types

This extension has no resource types defined.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

GMP_ROUND_ZERO (integer)

GMP_ROUND_PLUSINF (integer)

GMP_ROUND_MINUSINF (integer)

Examples

Example 1. Factorial function using GMP

<?php
function fact ($x) {
    if ($x <= 1) 
        return 1;
    else
        return gmp_mul ($x, fact ($x-1));
}

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

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

See Also

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

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


add a note add a note User Contributed Notes
GMP functions
helvecio_oliveira at yahoo dot com dot br
16-Oct-2003 03:51
=============================================================
A set of very nice functions to handle IP Address with gmplib:

The best way to store a range into a database is store:
dNet ..... decimal representation of a Net
dMask .... decimal representation of a Mask

All another parameters can be calculated.

<?
/*
f_ip2dec($a) ................... IP string to decimal
f_dec2ip($a) ................... decimal to IP string

f_dec2ipall($dNet,$dMask) ...... decimal Net and Mask to an Array with several IP parameters

f_dec2cidr($a) ................. decimal Mask to CIDR

f_and($a,$b) ................... and
f_or($a,$b) .................... or
f_xor($a,$b) ................... xor
f_not($a) ...................... not
f_dec2bin($a) .................. decimal to binary string
f_bin2dec($a) .................. binary string to decimal
*/

function f_and($a,$b){
$a=gmp_init(strval($a));
$b=gmp_init(strval($b));
$d=gmp_and($a,$b);
return 
floatval(gmp_strval($d));
}

function 
f_or($a,$b){
$a=gmp_init(strval($a));
$b=gmp_init(strval($b));
$d=gmp_or($a,$b);
return 
floatval(gmp_strval($d));
}

function 
f_xor($a,$b){
$a=gmp_init(strval($a));
$b=gmp_init(strval($b));
$d=gmp_xor($a,$b);
return 
floatval(gmp_strval($d));
}

function 
f_not($a){
$a=gmp_init(strval($a));
$d=gmp_strval($a,2);
$d=str_replace("1","x",$d);
$d=str_replace("0","1",$d);
$d=str_replace("x","0",$d);
$d=gmp_init($d,2);
return 
floatval(gmp_strval($d,10));
}

function 
f_dec2bin($a){
$a=gmp_init(strval($a));
return 
gmp_strval($a,2);
}

function 
f_bin2dec($a){
$a=gmp_init(strval($a),2);
return 
floatval(gmp_strval($a,10));
}

function 
f_ip2dec($a){
$d 0.0;
$b explode("."$a,4);
for (
$i 0$i 4$i++) {
       
$d *= 256.0;
       
$d += $b[$i];
    };
return 
$d;
}

function 
f_dec2ip($a){
   
$b=array(0,0,0,0);
   
$c 16777216.0;
   
$a += 0.0;
    for (
$i 0$i 4$i++) {
       
$k = (int) ($a $c);
       
$a -= $c $k;
       
$b[$i]= $k;
       
$c /=256.0;
    };
   
$d=join('.'$b);
    return(
$d);
}

function 
f_dec2cidr($a){
$a=gmp_init(strval($a));
$d=strlen(str_replace("0","",gmp_strval($a,2)));
return 
$d;
}

function 
f_dec2ipall($dNet,$dMask){
 
$dWildCard=f_not($dMask);
 
$IpAll["Net"]=f_dec2ip($dNet);
 
$IpAll["Mask"]=f_dec2ip($dMask);
 
$IpAll["WildCard"]=f_dec2ip($dWildCard);
 
$IpAll["Cidr"]=f_dec2cidr($dMask);
 
$IpAll["Bcast"]=f_dec2ip(f_or($dNet,$dWildCard));
 
$IpAll["nIp"]=$dWildCard+1;
 
$IpAll["nIpUtil"]=$dWildCard-1;
  if(
$IpAll["nIp"] > 2){
       
$IpAll["IpFrom"]=f_dec2ip($dNet+1);
       
$IpAll["IpTo"]=f_dec2ip($dNet+$dWildCard-1);
  }
  else
  {
       
$IpAll["IpFrom"]="-";
       
$IpAll["IpTo"]="-";
       
$IpAll["nIpUtil"]=0;
  }
  return 
$IpAll;
}

?>

=============================================================
GMP install steps in Mandrake 9.1:
----------------------------------------------------------
cp -r /usr/src/php-devel/extensions/gmp /tmp/gmp
cd /tmp/gmp
phpize
./configure
make install
echo "extension = gmp.so" > /etc/php/90_gmp.ini

Restart apache web server.
----------------------------------------------------------
gmp.so is in:
/usr/lib/php/extensions/

look in phpinfo, the string:
/etc/php/90_gmp.ini

Needs these tools:
autoconf
automake
libtool
m4
php430-devel-430-11mdk.rpm
all rpm愀 that are envolved to run and compile gmp (*gmp*.rpm)

Some docs about self contained extensions:
/usr/share/doc/php430-devel-430/SELF-CONTAINED-EXTENSIONS
=============================================================
php at prezent dot nl
08-Jul-2003 06:57
Notice there are some broken gmp libs out there ..
if our code is not working try the following.
<code>
$BIT=gmp_init(0,10);
for( $i=0; $i<=50; $i++) {
      echo $i." ".gmp_scan1($BIT,$i).'<BR />';
}
</code>
if only one of them returns something other than -1
your libgmp is broken

<textdomaingmp_abs>
 Last updated: Thu, 21 Aug 2003
show source | credits | sitemap | mirror sites 
Copyright © 2001-2003 The PHP Group
All rights reserved.
This mirror generously provided by: http://php.mirrors.ilisys.com.au/
Last updated: Sat 01 Nov 2003 04:13:36 EST EST