(PHP 5 >= 5.6.0, PHP 7, PHP 8)
gmp_root — Take the integer part of nth root
$num
$nth
Takes the nth root of num and returns the integer component of the result.
nth
num
GMP 对象或 int ，或数字string。
The positive root to take of num.
The integer component of the resultant root, as a GMP number.