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