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Diffstat (limited to 'src/pkg/math/atan2.go')
-rw-r--r-- | src/pkg/math/atan2.go | 71 |
1 files changed, 0 insertions, 71 deletions
diff --git a/src/pkg/math/atan2.go b/src/pkg/math/atan2.go deleted file mode 100644 index d84b332c9..000000000 --- a/src/pkg/math/atan2.go +++ /dev/null @@ -1,71 +0,0 @@ -// Copyright 2009 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 - -// Atan2 returns the arc tangent of y/x, using -// the signs of the two to determine the quadrant -// of the return value. -// -// Special cases are (in order): -// Atan2(y, NaN) = NaN -// Atan2(NaN, x) = NaN -// Atan2(+0, x>=0) = +0 -// Atan2(-0, x>=0) = -0 -// Atan2(+0, x<=-0) = +Pi -// Atan2(-0, x<=-0) = -Pi -// Atan2(y>0, 0) = +Pi/2 -// Atan2(y<0, 0) = -Pi/2 -// Atan2(+Inf, +Inf) = +Pi/4 -// Atan2(-Inf, +Inf) = -Pi/4 -// Atan2(+Inf, -Inf) = 3Pi/4 -// Atan2(-Inf, -Inf) = -3Pi/4 -// Atan2(y, +Inf) = 0 -// Atan2(y>0, -Inf) = +Pi -// Atan2(y<0, -Inf) = -Pi -// Atan2(+Inf, x) = +Pi/2 -// Atan2(-Inf, x) = -Pi/2 -func Atan2(y, x float64) float64 - -func atan2(y, x float64) float64 { - // special cases - switch { - case IsNaN(y) || IsNaN(x): - return NaN() - case y == 0: - if x >= 0 && !Signbit(x) { - return Copysign(0, y) - } - return Copysign(Pi, y) - case x == 0: - return Copysign(Pi/2, y) - case IsInf(x, 0): - if IsInf(x, 1) { - switch { - case IsInf(y, 0): - return Copysign(Pi/4, y) - default: - return Copysign(0, y) - } - } - switch { - case IsInf(y, 0): - return Copysign(3*Pi/4, y) - default: - return Copysign(Pi, y) - } - case IsInf(y, 0): - return Copysign(Pi/2, y) - } - - // Call atan and determine the quadrant. - q := Atan(y / x) - if x < 0 { - if q <= 0 { - return q + Pi - } - return q - Pi - } - return q -} |