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// 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 {
if haveArchMax {
return archMax(x, y)
}
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 {
if haveArchMin {
return archMin(x, y)
}
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
}
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