Source file src/pkg/math/nextafter.go
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 // Nextafter returns the next representable value after x towards y. 8 // If x == y, then x is returned. 9 // 10 // Special cases are: 11 // Nextafter(NaN, y) = NaN 12 // Nextafter(x, NaN) = NaN 13 func Nextafter(x, y float64) (r float64) { 14 switch { 15 case IsNaN(x) || IsNaN(y): // special case 16 r = NaN() 17 case x == y: 18 r = x 19 case x == 0: 20 r = Copysign(Float64frombits(1), y) 21 case (y > x) == (x > 0): 22 r = Float64frombits(Float64bits(x) + 1) 23 default: 24 r = Float64frombits(Float64bits(x) - 1) 25 } 26 return 27 }