Source file src/pkg/math/cmplx/exp.go
1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package cmplx 6 7 import "math" 8 9 // The original C code, the long comment, and the constants 10 // below are from http://netlib.sandia.gov/cephes/c9x-complex/clog.c. 11 // The go code is a simplified version of the original C. 12 // 13 // Cephes Math Library Release 2.8: June, 2000 14 // Copyright 1984, 1987, 1989, 1992, 2000 by Stephen L. Moshier 15 // 16 // The readme file at http://netlib.sandia.gov/cephes/ says: 17 // Some software in this archive may be from the book _Methods and 18 // Programs for Mathematical Functions_ (Prentice-Hall or Simon & Schuster 19 // International, 1989) or from the Cephes Mathematical Library, a 20 // commercial product. In either event, it is copyrighted by the author. 21 // What you see here may be used freely but it comes with no support or 22 // guarantee. 23 // 24 // The two known misprints in the book are repaired here in the 25 // source listings for the gamma function and the incomplete beta 26 // integral. 27 // 28 // Stephen L. Moshier 29 // [email protected] 30 31 // Complex exponential function 32 // 33 // DESCRIPTION: 34 // 35 // Returns the complex exponential of the complex argument z. 36 // 37 // If 38 // z = x + iy, 39 // r = exp(x), 40 // then 41 // w = r cos y + i r sin y. 42 // 43 // ACCURACY: 44 // 45 // Relative error: 46 // arithmetic domain # trials peak rms 47 // DEC -10,+10 8700 3.7e-17 1.1e-17 48 // IEEE -10,+10 30000 3.0e-16 8.7e-17 49 50 // Exp returns e**x, the base-e exponential of x. 51 func Exp(x complex128) complex128 { 52 r := math.Exp(real(x)) 53 s, c := math.Sincos(imag(x)) 54 return complex(r*c, r*s) 55 }