blob: cf06f30d562e209ffc329701a379bec863772c91 [file] [log] [blame]
 // Copyright 2010 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package math // Dim returns the maximum of x-y or 0. // // Special cases are: // Dim(+Inf, +Inf) = NaN // Dim(-Inf, -Inf) = NaN // Dim(x, NaN) = Dim(NaN, x) = NaN func Dim(x, y float64) float64 { // The special cases result in NaN after the subtraction: // +Inf - +Inf = NaN // -Inf - -Inf = NaN // NaN - y = NaN // x - NaN = NaN v := x - y if v <= 0 { // v is negative or 0 return 0 } // v is positive or NaN return v } // Max returns the larger of x or y. // // Special cases are: // Max(x, +Inf) = Max(+Inf, x) = +Inf // Max(x, NaN) = Max(NaN, x) = NaN // Max(+0, ±0) = Max(±0, +0) = +0 // Max(-0, -0) = -0 func Max(x, y float64) float64 { return max(x, y) } func max(x, y float64) float64 { // special cases switch { case IsInf(x, 1) || IsInf(y, 1): return Inf(1) case IsNaN(x) || IsNaN(y): return NaN() case x == 0 && x == y: if Signbit(x) { return y } return x } if x > y { return x } return y } // Min returns the smaller of x or y. // // Special cases are: // Min(x, -Inf) = Min(-Inf, x) = -Inf // Min(x, NaN) = Min(NaN, x) = NaN // Min(-0, ±0) = Min(±0, -0) = -0 func Min(x, y float64) float64 { return min(x, y) } func min(x, y float64) float64 { // special cases switch { case IsInf(x, -1) || IsInf(y, -1): return Inf(-1) case IsNaN(x) || IsNaN(y): return NaN() case x == 0 && x == y: if Signbit(x) { return x } return y } if x < y { return x } return y }