summaryrefslogtreecommitdiff
path: root/libgo/go/math/asin.go
diff options
context:
space:
mode:
authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/math/asin.go
downloadcbb-gcc-4.6.4-15d2061ac0796199866debe9ac87130894b0cdd3.tar.bz2
cbb-gcc-4.6.4-15d2061ac0796199866debe9ac87130894b0cdd3.tar.xz
obtained gcc-4.6.4.tar.bz2 from upstream website;upstream
verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository.
Diffstat (limited to 'libgo/go/math/asin.go')
-rw-r--r--libgo/go/math/asin.go50
1 files changed, 50 insertions, 0 deletions
diff --git a/libgo/go/math/asin.go b/libgo/go/math/asin.go
new file mode 100644
index 000000000..3bace8ff1
--- /dev/null
+++ b/libgo/go/math/asin.go
@@ -0,0 +1,50 @@
+// 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 of x.
+//
+// Special cases are:
+// Asin(±0) = ±0
+// Asin(x) = NaN if x < -1 or x > 1
+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 of x.
+//
+// Special case is:
+// Acos(x) = NaN if x < -1 or x > 1
+func Acos(x float64) float64 { return Pi/2 - Asin(x) }