From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; 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. --- libgo/go/math/sinh.go | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 libgo/go/math/sinh.go (limited to 'libgo/go/math/sinh.go') diff --git a/libgo/go/math/sinh.go b/libgo/go/math/sinh.go new file mode 100644 index 000000000..23a8719f2 --- /dev/null +++ b/libgo/go/math/sinh.go @@ -0,0 +1,68 @@ +// 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 hyperbolic sine and cosine. + + The exponential func is called for arguments + greater in magnitude than 0.5. + + A series is used for arguments smaller in magnitude than 0.5. + + Cosh(x) is computed from the exponential func for + all arguments. +*/ + +// Sinh returns the hyperbolic sine of x. +func Sinh(x float64) float64 { + // The coefficients are #2029 from Hart & Cheney. (20.36D) + const ( + P0 = -0.6307673640497716991184787251e+6 + P1 = -0.8991272022039509355398013511e+5 + P2 = -0.2894211355989563807284660366e+4 + P3 = -0.2630563213397497062819489e+2 + Q0 = -0.6307673640497716991212077277e+6 + Q1 = 0.1521517378790019070696485176e+5 + Q2 = -0.173678953558233699533450911e+3 + ) + + sign := false + if x < 0 { + x = -x + sign = true + } + + var temp float64 + switch true { + case x > 21: + temp = Exp(x) / 2 + + case x > 0.5: + temp = (Exp(x) - Exp(-x)) / 2 + + default: + sq := x * x + temp = (((P3*sq+P2)*sq+P1)*sq + P0) * x + temp = temp / (((sq+Q2)*sq+Q1)*sq + Q0) + } + + if sign { + temp = -temp + } + return temp +} + +// Cosh returns the hyperbolic cosine of x. +func Cosh(x float64) float64 { + if x < 0 { + x = -x + } + if x > 21 { + return Exp(x) / 2 + } + return (Exp(x) + Exp(-x)) / 2 +} -- cgit v1.2.3