Subversion Repositories openrisc

// 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)

}