mirror of
https://gitlab.com/sortix/sortix.git
synced 2023-02-13 20:55:38 -05:00
5980be9b3c
This work is based in part on code from NetBSD libm, libc and kernel. The library is partly public domain and partly BSD-style licensed.
123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
/* $NetBSD: cephes_subrf.c,v 1.1 2007/08/20 16:01:34 drochner 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_subrf.h"
|
|
|
|
/* calculate cosh and sinh */
|
|
|
|
void
|
|
_cchshf(float x, float *c, float *s)
|
|
{
|
|
float e, ei;
|
|
|
|
if (fabsf(x) <= 0.5f) {
|
|
*c = coshf(x);
|
|
*s = sinhf(x);
|
|
} else {
|
|
e = expf(x);
|
|
ei = 0.5f / e;
|
|
e = 0.5f * e;
|
|
*s = e - ei;
|
|
*c = e + ei;
|
|
}
|
|
}
|
|
|
|
/* Program to subtract nearest integer multiple of PI */
|
|
|
|
/* extended precision value of PI: */
|
|
static const double DP1 = 3.140625;
|
|
static const double DP2 = 9.67502593994140625E-4;
|
|
static const double DP3 = 1.509957990978376432E-7;
|
|
#define MACHEPF 3.0e-8
|
|
|
|
float
|
|
_redupif(float x)
|
|
{
|
|
float t;
|
|
long i;
|
|
|
|
t = x / (float)M_PI;
|
|
if (t >= 0.0f)
|
|
t += 0.5f;
|
|
else
|
|
t -= 0.5f;
|
|
|
|
i = t; /* the multiple */
|
|
t = i;
|
|
t = ((x - t * DP1) - t * DP2) - t * DP3;
|
|
return t;
|
|
}
|
|
|
|
/* Taylor series expansion for cosh(2y) - cos(2x) */
|
|
|
|
float
|
|
_ctansf(float complex z)
|
|
{
|
|
float f, x, x2, y, y2, rn, t, d;
|
|
|
|
x = fabsf(2.0f * crealf(z));
|
|
y = fabsf(2.0f * cimagf(z));
|
|
|
|
x = _redupif(x);
|
|
|
|
x = x * x;
|
|
y = y * y;
|
|
x2 = 1.0f;
|
|
y2 = 1.0f;
|
|
f = 1.0f;
|
|
rn = 0.0f;
|
|
d = 0.0f;
|
|
do {
|
|
rn += 1.0f;
|
|
f *= rn;
|
|
rn += 1.0f;
|
|
f *= rn;
|
|
x2 *= x;
|
|
y2 *= y;
|
|
t = y2 + x2;
|
|
t /= f;
|
|
d += t;
|
|
|
|
rn += 1.0f;
|
|
f *= rn;
|
|
rn += 1.0f;
|
|
f *= rn;
|
|
x2 *= x;
|
|
y2 *= y;
|
|
t = y2 - x2;
|
|
t /= f;
|
|
d += t;
|
|
} while (fabsf(t/d) > MACHEPF);
|
|
return d;
|
|
}
|