github.com/ice-blockchain/go/src@v0.0.0-20240403114104-1564d284e521/math/dim.go (about) 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 // Dim returns the maximum of x-y or 0. 8 // 9 // Special cases are: 10 // 11 // Dim(+Inf, +Inf) = NaN 12 // Dim(-Inf, -Inf) = NaN 13 // Dim(x, NaN) = Dim(NaN, x) = NaN 14 func Dim(x, y float64) float64 { 15 // The special cases result in NaN after the subtraction: 16 // +Inf - +Inf = NaN 17 // -Inf - -Inf = NaN 18 // NaN - y = NaN 19 // x - NaN = NaN 20 v := x - y 21 if v <= 0 { 22 // v is negative or 0 23 return 0 24 } 25 // v is positive or NaN 26 return v 27 } 28 29 // Max returns the larger of x or y. 30 // 31 // Special cases are: 32 // 33 // Max(x, +Inf) = Max(+Inf, x) = +Inf 34 // Max(x, NaN) = Max(NaN, x) = NaN 35 // Max(+0, ±0) = Max(±0, +0) = +0 36 // Max(-0, -0) = -0 37 // 38 // Note that this differs from the built-in function max when called 39 // with NaN and +Inf. 40 func Max(x, y float64) float64 { 41 if haveArchMax { 42 return archMax(x, y) 43 } 44 return max(x, y) 45 } 46 47 func max(x, y float64) float64 { 48 // special cases 49 switch { 50 case IsInf(x, 1) || IsInf(y, 1): 51 return Inf(1) 52 case IsNaN(x) || IsNaN(y): 53 return NaN() 54 case x == 0 && x == y: 55 if Signbit(x) { 56 return y 57 } 58 return x 59 } 60 if x > y { 61 return x 62 } 63 return y 64 } 65 66 // Min returns the smaller of x or y. 67 // 68 // Special cases are: 69 // 70 // Min(x, -Inf) = Min(-Inf, x) = -Inf 71 // Min(x, NaN) = Min(NaN, x) = NaN 72 // Min(-0, ±0) = Min(±0, -0) = -0 73 // 74 // Note that this differs from the built-in function min when called 75 // with NaN and -Inf. 76 func Min(x, y float64) float64 { 77 if haveArchMin { 78 return archMin(x, y) 79 } 80 return min(x, y) 81 } 82 83 func min(x, y float64) float64 { 84 // special cases 85 switch { 86 case IsInf(x, -1) || IsInf(y, -1): 87 return Inf(-1) 88 case IsNaN(x) || IsNaN(y): 89 return NaN() 90 case x == 0 && x == y: 91 if Signbit(x) { 92 return x 93 } 94 return y 95 } 96 if x < y { 97 return x 98 } 99 return y 100 }