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/cmath/log.go | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 libgo/go/cmath/log.go (limited to 'libgo/go/cmath/log.go') diff --git a/libgo/go/cmath/log.go b/libgo/go/cmath/log.go new file mode 100644 index 000000000..8e6964fee --- /dev/null +++ b/libgo/go/cmath/log.go @@ -0,0 +1,64 @@ +// Copyright 2010 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 cmath + +import "math" + +// The original C code, the long comment, and the constants +// below are from http://netlib.sandia.gov/cephes/c9x-complex/clog.c. +// The go code is a simplified version of the original C. +// +// Cephes Math Library Release 2.8: June, 2000 +// Copyright 1984, 1987, 1989, 1992, 2000 by Stephen L. Moshier +// +// The readme file at http://netlib.sandia.gov/cephes/ says: +// Some software in this archive may be from the book _Methods and +// Programs for Mathematical Functions_ (Prentice-Hall or Simon & Schuster +// International, 1989) or from the Cephes Mathematical Library, a +// commercial product. In either event, it is copyrighted by the author. +// What you see here may be used freely but it comes with no support or +// guarantee. +// +// The two known misprints in the book are repaired here in the +// source listings for the gamma function and the incomplete beta +// integral. +// +// Stephen L. Moshier +// moshier@na-net.ornl.gov + +// Complex natural logarithm +// +// DESCRIPTION: +// +// Returns complex logarithm to the base e (2.718...) of +// the complex argument z. +// +// If +// z = x + iy, r = sqrt( x**2 + y**2 ), +// then +// w = log(r) + i arctan(y/x). +// +// The arctangent ranges from -PI to +PI. +// +// ACCURACY: +// +// Relative error: +// arithmetic domain # trials peak rms +// DEC -10,+10 7000 8.5e-17 1.9e-17 +// IEEE -10,+10 30000 5.0e-15 1.1e-16 +// +// Larger relative error can be observed for z near 1 +i0. +// In IEEE arithmetic the peak absolute error is 5.2e-16, rms +// absolute error 1.0e-16. + +// Log returns the natural logarithm of x. +func Log(x complex128) complex128 { + return complex(math.Log(Abs(x)), Phase(x)) +} + +// Log10 returns the decimal logarithm of x. +func Log10(x complex128) complex128 { + return math.Log10E * Log(x) +} -- cgit v1.2.3