PHP 7.2.0 Release Candidate 2 Released

hypot

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

hypot Calculate the length of the hypotenuse of a right-angle triangle

Description

float hypot ( float $x , float $y )

hypot() returns the length of the hypotenuse of a right-angle triangle with sides of length x and y, or the distance of the point (x, y) from the origin. This is equivalent to sqrt(x*x + y*y).

Parameters

x

Length of first side

y

Length of second side

Return Values

Calculated length of the hypotenuse

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User Contributed Notes 2 notes

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0
Hayley Watson
15 days ago
If you need a higher-dimensional diagonal length (norm), you can exploit the fact that sqrt(x*x+y*y+z*z) == sqrt(x*x+sqrt(y*y+z*z)). In other words hypot(x, y, z)==hypot(x, hypot(y, z)).

To be generic about it....
<?php

function norm(...$args)
{
    return
array_reduce($args, 'hypot', 0);
}

?>
up
-8
robinv at ecosse dot net
13 years ago
A simpler approach would be to allow an arbitrary number of parameters. That would allow for whatever number of dimensions you want *and* it would be backwards compatible with the current implementation.

<?php

function hypo()
{
   
$sum = 0;
    foreach (
func_get_args() as $dimension) {
        if (!
is_numeric($dimension)) return -1;
       
$sum += pow($dimension, 2);
    }
    return
sqrt($sum);
}

print
hypo();          // vector in 0 dimensions, magnitude = 0.
print hypo(1);         // vector in 1 dimension,  magnitude = 1.
print hypo(3, 4);       // vector in 2 dimensions, magnitude = 5.
print hypo(2, 3, 6);     // vector in 3 dimensions, magnitude = 7.

?>
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