121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
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/* $NetBSD: casinl.c,v 1.1 2014/10/10 00:48:18 christos Exp $ */
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/*-
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* Copyright (c) 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software written by Stephen L. Moshier.
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* It is redistributed by the NetBSD Foundation by permission of the author.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <complex.h>
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#include <math.h>
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#ifdef __weak_alias
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__weak_alias(casinl, _casinl)
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#endif
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long double complex
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casinl(long double complex z)
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{
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long double complex w;
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long double complex ca, ct, zz, z2;
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long double x, y;
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x = creall(z);
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y = cimagl(z);
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#if 0 /* MD: test is incorrect, casin(>1) is defined */
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if (y == 0.0L) {
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if (fabsl(x) > 1.0L) {
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w = M_PI_2L + 0.0L * I;
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#if 0
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mtherr ("casinl", DOMAIN);
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#endif
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} else {
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w = asinl(x) + 0.0L * I;
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}
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return w;
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}
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#endif
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/* Power series expansion */
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/*
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b = cabsl(z);
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if( b < 0.125L )
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{
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z2.r = (x - y) * (x + y);
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z2.i = 2.0L * x * y;
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cn = 1.0L;
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n = 1.0L;
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ca.r = x;
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ca.i = y;
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sum.r = x;
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sum.i = y;
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do
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{
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ct.r = z2.r * ca.r - z2.i * ca.i;
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ct.i = z2.r * ca.i + z2.i * ca.r;
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ca.r = ct.r;
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ca.i = ct.i;
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cn *= n;
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n += 1.0;
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cn /= n;
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n += 1.0;
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b = cn/n;
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ct.r *= b;
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ct.i *= b;
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sum.r += ct.r;
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sum.i += ct.i;
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b = fabsl(ct.r) + fabsl(ct.i);
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}
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while( b > MACHEPL );
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w->r = sum.r;
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w->i = sum.i;
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return;
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}
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*/
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ca = x + y * I;
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ct = ca * I;
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/* sqrtl( 1 - z*z) */
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/* cmull( &ca, &ca, &zz ) */
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/*x * x - y * y */
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zz = (x - y) * (x + y) + (2.0L * x * y) * I;
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zz = 1.0L - creall(zz) - cimagl(zz) * I;
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z2 = csqrtl(zz);
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zz = ct + z2;
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zz = clogl(zz);
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/* multiply by 1/i = -i */
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w = zz * (-1.0L * I);
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return w;
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}
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