PHP | gmp_root() Function

The gmp_root() is an in-built function in PHP which returns the integer part of the N-th root of a GMP number(GNU Multiple Precision: For large numbers).
Syntax: 
 

gmp_root( $num, $n )

Parameters: The function accepts two mandatory parameters $num and $n. 
 

1. $num - This is the GMP number whose integer part of the n-th root is returned. The parameter is a GMP object in PHP version 5.6 and later, or we are also allowed to pass a numeric string provided that it is possible to convert that string to a number.
2. $n - the positive n-th root of the number. It is an integer value. 
    

Return Value: This function returns a positive GMP number which is the integer part of the N-th root of the $num. 
Examples: 
 

Input : $num = "20" $n = 2
Output : 4 

Input : $num = "9" $n = 2
Output : 2

Below programs illustrate the gmp_root() function:
Program 1: The program below demonstrates the working of gmp_root() function when GMP number is passed as argument.. 
 

<?php
// PHP program to calculate the 
// integer part of N-th root of  
// a GMP number 

// GMP number as arguments 
$num = gmp_init("1001", 2); 
$n = 3;

// function calculates the pow raised to 
// number modulo mod  
    
//  integer part of cubic root of 9
$root = gmp_root($num, $n);  

// gmp_strval Convert GMP number to string 
// representation in given base(default 10).
echo gmp_strval($root, 2);
?>

Output: 
 

10

Program 2: The program below demonstrates the working of gmp_root() when numeric string is passed as an argument. 
 

<?php
// PHP program to calculate the 
// integer part of N-th root of  
// a GMP number 

// GMP number as arguments 
$num = "9"; 
$n = 3;

// function calculates the pow raised to 
// number modulo mod  
    
// integer part of cubic root of 9
$root = gmp_root($num, $n);  

echo $root;
?>

Output: 
 

2

Program 3: Program to find the integer part of a square root of a number. 
 

<?php
// PHP program to calculate the 
// integer part of N-th root of  
// a GMP number 

// GMP number as arguments 
$num = "25"; 
$n = 2;

// function calculates the pow raised to 
// number modulo mod  
    
// integer part of square root of 25
$root = gmp_root($num, $n);  

echo $root;
?>

Output: 
 

5

Reference: 
https://www.php.net/manual/en/function.gmp-root.php