mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-11 03:52:59 +00:00
46 lines
822 B
Go
46 lines
822 B
Go
// Copyright 2010 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package math
|
|
|
|
/*
|
|
Hypot -- sqrt(p*p + q*q), but overflows only if the result does.
|
|
*/
|
|
|
|
// Hypot returns Sqrt(p*p + q*q), taking care to avoid
|
|
// unnecessary overflow and underflow.
|
|
//
|
|
// Special cases are:
|
|
// Hypot(±Inf, q) = +Inf
|
|
// Hypot(p, ±Inf) = +Inf
|
|
// Hypot(NaN, q) = NaN
|
|
// Hypot(p, NaN) = NaN
|
|
func Hypot(p, q float64) float64 {
|
|
return hypot(p, q)
|
|
}
|
|
|
|
func hypot(p, q float64) float64 {
|
|
// special cases
|
|
switch {
|
|
case IsInf(p, 0) || IsInf(q, 0):
|
|
return Inf(1)
|
|
case IsNaN(p) || IsNaN(q):
|
|
return NaN()
|
|
}
|
|
if p < 0 {
|
|
p = -p
|
|
}
|
|
if q < 0 {
|
|
q = -q
|
|
}
|
|
if p < q {
|
|
p, q = q, p
|
|
}
|
|
if p == 0 {
|
|
return 0
|
|
}
|
|
q = q / p
|
|
return p * Sqrt(1+q*q)
|
|
}
|