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https://github.com/golang/go
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277eddb8f2
Change-Id: I3419d6247fbff36aa1ed5451bb3cfb7502c3d07e Reviewed-on: https://go-review.googlesource.com/5030 Reviewed-by: David Crawshaw <crawshaw@golang.org>
50 lines
1.2 KiB
Go
50 lines
1.2 KiB
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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// Nextafter32 returns the next representable float32 value after x towards y.
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//
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// Special cases are:
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// Nextafter32(x, x) = x
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// Nextafter32(NaN, y) = NaN
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// Nextafter32(x, NaN) = NaN
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func Nextafter32(x, y float32) (r float32) {
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switch {
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case IsNaN(float64(x)) || IsNaN(float64(y)): // special case
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r = float32(NaN())
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case x == y:
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r = x
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case x == 0:
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r = float32(Copysign(float64(Float32frombits(1)), float64(y)))
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case (y > x) == (x > 0):
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r = Float32frombits(Float32bits(x) + 1)
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default:
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r = Float32frombits(Float32bits(x) - 1)
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}
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return
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}
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// Nextafter returns the next representable float64 value after x towards y.
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//
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// Special cases are:
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// Nextafter(x, x) = x
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// Nextafter(NaN, y) = NaN
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// Nextafter(x, NaN) = NaN
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func Nextafter(x, y float64) (r float64) {
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switch {
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case IsNaN(x) || IsNaN(y): // special case
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r = NaN()
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case x == y:
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r = x
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case x == 0:
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r = Copysign(Float64frombits(1), y)
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case (y > x) == (x > 0):
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r = Float64frombits(Float64bits(x) + 1)
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default:
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r = Float64frombits(Float64bits(x) - 1)
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}
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return
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}
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