to robinv at ecosse dot net:
hypo(a, b, c) === hypo(a, hypo(b, c))
hypo(a, b, c, d) === hypo(a, hypo(b, hypo(c, d)))
...
hypot
(PHP 4 >= 4.1.0, PHP 5)
hypot — Calculate the length of the hypotenuse of a right-angle triangle
Описание
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).
Список параметров
- x
-
Length of first side
- y
-
Length of second side
Возвращаемые значения
Calculated length of the hypotenuse
User Contributed Notes
hypot
hypot
</Life>.org
10-Aug-2006 09:56
10-Aug-2006 09:56
R. Victor Klassen
24-Jun-2005 03:03
24-Jun-2005 03:03
A correct implementation of hypot( x, y ) avoids the overflow that might otherwise happen if either x or y is large enough that when squared it would overflow, but the answer is small enough not to cause overflow.
robinv at ecosse dot net
07-Jan-2004 05:18
07-Jan-2004 05:18
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.
?>