| /* $NetBSD: cephes_subrl.c,v 1.2 2014/10/10 14:06:40 christos Exp $ */ |
| |
| /*- |
| * Copyright (c) 2007 The NetBSD Foundation, Inc. |
| * All rights reserved. |
| * |
| * This code is derived from software written by Stephen L. Moshier. |
| * It is redistributed by the NetBSD Foundation by permission of the author. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "../src/namespace.h" |
| #include <complex.h> |
| #include <math.h> |
| #include "cephes_subrl.h" |
| |
| /* calculate cosh and sinh */ |
| |
| void |
| _cchshl(long double x, long double *c, long double *s) |
| { |
| long double e, ei; |
| |
| if (fabsl(x) <= 0.5L) { |
| *c = coshl(x); |
| *s = sinhl(x); |
| } else { |
| e = expl(x); |
| ei = 0.5L / e; |
| e = 0.5L * e; |
| *s = e - ei; |
| *c = e + ei; |
| } |
| } |
| |
| /* Program to subtract nearest integer multiple of PI */ |
| |
| /* extended precision value of PI: */ |
| static const long double DP1 = 3.14159265358979323829596852490908531763125L; |
| static const long double DP2 = 1.6667485837041756656403424829301998703007e-19L; |
| #ifndef __vax__ |
| static const long double DP3 = 1.8830410776607851167459095484560349402753e-39L; |
| #define MACHEPL 1.1e-38L |
| #else |
| static const long double DP3 = 0L; |
| #define MACHEPL 1.1e-19L |
| #endif |
| |
| long double |
| _redupil(long double x) |
| { |
| long double t; |
| long long i; |
| |
| t = x / M_PIL; |
| if (t >= 0.0L) |
| t += 0.5L; |
| else |
| t -= 0.5L; |
| |
| i = t; /* the multiple */ |
| t = i; |
| t = ((x - t * DP1) - t * DP2) - t * DP3; |
| return t; |
| } |
| |
| /* Taylor series expansion for cosh(2y) - cos(2x) */ |
| |
| long double |
| _ctansl(long double complex z) |
| { |
| long double f, x, x2, y, y2, rn, t; |
| long double d; |
| |
| x = fabsl(2.0L * creall(z)); |
| y = fabsl(2.0L * cimagl(z)); |
| |
| x = _redupil(x); |
| |
| x = x * x; |
| y = y * y; |
| x2 = 1.0; |
| y2 = 1.0; |
| f = 1.0; |
| rn = 0.0; |
| d = 0.0; |
| do { |
| rn += 1.0L; |
| f *= rn; |
| rn += 1.0L; |
| f *= rn; |
| x2 *= x; |
| y2 *= y; |
| t = y2 + x2; |
| t /= f; |
| d += t; |
| |
| rn += 1.0L; |
| f *= rn; |
| rn += 1.0L; |
| f *= rn; |
| x2 *= x; |
| y2 *= y; |
| t = y2 - x2; |
| t /= f; |
| d += t; |
| } while (fabsl(t/d) > MACHEPL); |
| return d; |
| } |