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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:23:18 +0000 |
commit | 43a123c1ae6613b3efeed291fa552ecd909d3acf (patch) | |
tree | fd92518b7024bc74031f78a1cf9e454b65e73665 /src/math/asin.go | |
parent | Initial commit. (diff) | |
download | golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip |
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/math/asin.go')
-rw-r--r-- | src/math/asin.go | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/math/asin.go b/src/math/asin.go new file mode 100644 index 0000000..8e1b2ab --- /dev/null +++ b/src/math/asin.go @@ -0,0 +1,67 @@ +// 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 + +/* + Floating-point arcsine and arccosine. + + They are implemented by computing the arctangent + after appropriate range reduction. +*/ + +// Asin returns the arcsine, in radians, of x. +// +// Special cases are: +// +// Asin(±0) = ±0 +// Asin(x) = NaN if x < -1 or x > 1 +func Asin(x float64) float64 { + if haveArchAsin { + return archAsin(x) + } + return asin(x) +} + +func asin(x float64) float64 { + if x == 0 { + return x // special case + } + sign := false + if x < 0 { + x = -x + sign = true + } + if x > 1 { + return NaN() // special case + } + + temp := Sqrt(1 - x*x) + if x > 0.7 { + temp = Pi/2 - satan(temp/x) + } else { + temp = satan(x / temp) + } + + if sign { + temp = -temp + } + return temp +} + +// Acos returns the arccosine, in radians, of x. +// +// Special case is: +// +// Acos(x) = NaN if x < -1 or x > 1 +func Acos(x float64) float64 { + if haveArchAcos { + return archAcos(x) + } + return acos(x) +} + +func acos(x float64) float64 { + return Pi/2 - Asin(x) +} |