Source file src/math/hypot.go

Documentation: math

		 1  // Copyright 2010 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package math
		 6  
		 7  /*
		 8  	Hypot -- sqrt(p*p + q*q), but overflows only if the result does.
		 9  */
		10  
		11  // Hypot returns Sqrt(p*p + q*q), taking care to avoid
		12  // unnecessary overflow and underflow.
		13  //
		14  // Special cases are:
		15  //	Hypot(±Inf, q) = +Inf
		16  //	Hypot(p, ±Inf) = +Inf
		17  //	Hypot(NaN, q) = NaN
		18  //	Hypot(p, NaN) = NaN
		19  func Hypot(p, q float64) float64 {
		20  	if haveArchHypot {
		21  		return archHypot(p, q)
		22  	}
		23  	return hypot(p, q)
		24  }
		25  
		26  func hypot(p, q float64) float64 {
		27  	// special cases
		28  	switch {
		29  	case IsInf(p, 0) || IsInf(q, 0):
		30  		return Inf(1)
		31  	case IsNaN(p) || IsNaN(q):
		32  		return NaN()
		33  	}
		34  	p, q = Abs(p), Abs(q)
		35  	if p < q {
		36  		p, q = q, p
		37  	}
		38  	if p == 0 {
		39  		return 0
		40  	}
		41  	q = q / p
		42  	return p * Sqrt(1+q*q)
		43  }
		44  

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