golang hypot 代码
文件路径：/src/math/hypot.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 {
if haveArchHypot {
return archHypot(p, q)
}
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()
}
p, q = Abs(p), Abs(q)
if p < q {
p, q = q, p
}
if p == 0 {
return 0
}
q = q / p
return p * Sqrt(1+q*q)
}