83 lines
1.7 KiB
Go
83 lines
1.7 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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// Dim returns the maximum of x-y or 0.
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//
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// Special cases are:
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// Dim(+Inf, +Inf) = NaN
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// Dim(-Inf, -Inf) = NaN
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// Dim(x, NaN) = Dim(NaN, x) = NaN
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func Dim(x, y float64) float64 {
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return dim(x, y)
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}
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func dim(x, y float64) float64 {
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return max(x-y, 0)
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}
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// Max returns the larger of x or y.
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//
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// Special cases are:
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// Max(x, +Inf) = Max(+Inf, x) = +Inf
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// Max(x, NaN) = Max(NaN, x) = NaN
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// Max(+0, ±0) = Max(±0, +0) = +0
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// Max(-0, -0) = -0
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func Max(x, y float64) float64 {
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return max(x, y)
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}
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func max(x, y float64) float64 {
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// TODO(rsc): Remove manual inlining of IsNaN, IsInf
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// when compiler does it for us
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// special cases
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switch {
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case x > MaxFloat64 || y > MaxFloat64: // IsInf(x, 1) || IsInf(y, 1):
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return Inf(1)
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case x != x || y != y: // IsNaN(x) || IsNaN(y):
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return NaN()
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case x == 0 && x == y:
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if Signbit(x) {
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return y
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}
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return x
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}
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if x > y {
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return x
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}
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return y
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}
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// Min returns the smaller of x or y.
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//
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// Special cases are:
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// Min(x, -Inf) = Min(-Inf, x) = -Inf
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// Min(x, NaN) = Min(NaN, x) = NaN
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// Min(-0, ±0) = Min(±0, -0) = -0
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func Min(x, y float64) float64 {
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return min(x, y)
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}
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func min(x, y float64) float64 {
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// TODO(rsc): Remove manual inlining of IsNaN, IsInf
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// when compiler does it for us
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// special cases
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switch {
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case x < -MaxFloat64 || y < -MaxFloat64: // IsInf(x, -1) || IsInf(y, -1):
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return Inf(-1)
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case x != x || y != y: // IsNaN(x) || IsNaN(y):
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return NaN()
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case x == 0 && x == y:
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if Signbit(x) {
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return x
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}
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return y
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}
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if x < y {
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return x
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}
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return y
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}
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