rsqrt - chung-leong/qb GitHub Wiki

rsqrt - Square root reciprocal

float rsqrt( float $x )

rsqrt() computes the reciprocal of the square root of x.

PARAMETERS

x - The number to process. It can be a scalar or an array.

Return Value:

The reciprocal of the square root of x or NAN for negative numbers. If x is an array, the return value is also an array.

Notes:

The result from rsqrt() might have less precision compared to 1 / sqrt( x ) due to the use of approximation.

Version

1.0 and above.