75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
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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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/* cpowf
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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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* float complex cpowf();
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* float complex a, z, w;
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*
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* w = cpowf (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 <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <complex.h>
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#include <math.h>
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#include "math_private.h"
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float complex
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cpowf(float complex a, float complex z)
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{
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float complex w;
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float x, y, r, theta, absa, arga;
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x = crealf(z);
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y = cimagf(z);
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absa = cabsf (a);
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if (absa == 0.0f) {
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return (CMPLXF(0.0f, 0.0f));
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}
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arga = cargf (a);
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r = powf (absa, x);
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theta = x * arga;
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if (y != 0.0f) {
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r = r * expf (-y * arga);
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theta = theta + y * logf (absa);
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}
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w = CMPLXF(r * cosf (theta), r * sinf (theta));
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return (w);
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}
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