85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
/* $OpenBSD: s_ccosf.c,v 1.2 2010/07/18 18:42:26 guenther Exp $ */
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/*
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* Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/* ccosf()
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*
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* Complex circular cosine
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*
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*
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*
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* SYNOPSIS:
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*
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* void ccosf();
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* cmplxf z, w;
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*
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* ccosf( &z, &w );
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*
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*
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*
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* DESCRIPTION:
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*
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* If
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* z = x + iy,
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*
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* then
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*
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* w = cos x cosh y - i sin x sinh y.
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*
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*
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*
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* ACCURACY:
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*
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* Relative error:
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* arithmetic domain # trials peak rms
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* IEEE -10,+10 30000 1.8e-7 5.5e-8
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*/
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#include <openlibm_complex.h>
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#include <openlibm_math.h>
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/* calculate cosh and sinh */
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static void
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_cchshf(float xx, float *c, float *s)
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{
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float x, e, ei;
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x = xx;
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if(fabsf(x) <= 0.5f) {
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*c = coshf(x);
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*s = sinhf(x);
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}
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else {
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e = expf(x);
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ei = 0.5f/e;
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e = 0.5f * e;
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*s = e - ei;
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*c = e + ei;
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}
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}
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float complex
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ccosf(float complex z)
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{
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float complex w;
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float ch, sh;
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_cchshf( cimagf(z), &ch, &sh );
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w = cosf( crealf(z) ) * ch + ( -sinf( crealf(z) ) * sh) * I;
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return (w);
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}
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