79 lines
1.9 KiB
C
79 lines
1.9 KiB
C
/* $OpenBSD: s_cpow.c,v 1.6 2013/07/03 04:46:36 espie 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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/* cpow
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*
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* Complex power function
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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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* double complex cpow();
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* double complex a, z, w;
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*
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* w = cpow (a, z);
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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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* Raises complex A to the complex Zth power.
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* Definition is per AMS55 # 4.2.8,
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* analytically equivalent to cpow(a,z) = cexp(z clog(a)).
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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 9.4e-15 1.5e-15
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*
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*/
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#include <float.h>
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#include <openlibm_complex.h>
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#include <openlibm_math.h>
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#include "math_private.h"
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OLM_DLLEXPORT double complex
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cpow(double complex a, double complex z)
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{
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double complex w;
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double x, y, r, theta, absa, arga;
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x = creal (z);
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y = cimag (z);
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absa = cabs (a);
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if (absa == 0.0) {
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return (0.0 + 0.0 * I);
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}
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arga = carg (a);
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r = pow (absa, x);
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theta = x * arga;
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if (y != 0.0) {
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r = r * exp (-y * arga);
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theta = theta + y * log (absa);
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}
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w = r * cos (theta) + (r * sin (theta)) * I;
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return (w);
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}
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#if LDBL_MANT_DIG == DBL_MANT_DIG
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__strong_alias(cpowl, cpow);
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#endif /* LDBL_MANT_DIG == DBL_MANT_DIG */
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