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// 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 computes Sqrt(p*p + q*q), taking care to avoid
// unnecessary overflow and underflow.
//
// Special cases are:
//      Hypot(p, q) = +Inf if p or q is infinite
//      Hypot(p, q) = NaN if p or q is 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)
}