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Diffstat (limited to 'newlib/libm/complex/cephes_subr.c')
| -rw-r--r-- | newlib/libm/complex/cephes_subr.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/newlib/libm/complex/cephes_subr.c b/newlib/libm/complex/cephes_subr.c new file mode 100644 index 000000000..5eacff6b0 --- /dev/null +++ b/newlib/libm/complex/cephes_subr.c @@ -0,0 +1,126 @@ +/* $NetBSD: cephes_subr.c,v 1.1 2007/08/20 16:01:33 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. + * + * imported and modified include for newlib 2010/10/03 + * Marco Atzeri <marco_atzeri@yahoo.it> + */ + +#include <complex.h> +#include <math.h> +#include "cephes_subr.h" + +/* calculate cosh and sinh */ + +void +_cchsh(double x, double *c, double *s) +{ + double e, ei; + + if (fabs(x) <= 0.5) { + *c = cosh(x); + *s = sinh(x); + } else { + e = exp(x); + ei = 0.5 / e; + e = 0.5 * e; + *s = e - ei; + *c = e + ei; + } +} + +/* Program to subtract nearest integer multiple of PI */ + +/* extended precision value of PI: */ +static const double DP1 = 3.14159265160560607910E0; +static const double DP2 = 1.98418714791870343106E-9; +static const double DP3 = 1.14423774522196636802E-17; +#define MACHEP 1.1e-16 + +double +_redupi(double x) +{ + double t; + long i; + + t = x / M_PI; + if (t >= 0.0) + t += 0.5; + else + t -= 0.5; + + i = t; /* the multiple */ + t = i; + t = ((x - t * DP1) - t * DP2) - t * DP3; + return t; +} + +/* Taylor series expansion for cosh(2y) - cos(2x) */ + +double +_ctans(double complex z) +{ + double f, x, x2, y, y2, rn, t; + double d; + + x = fabs(2.0 * creal(z)); + y = fabs(2.0 * cimag(z)); + + x = _redupi(x); + + x = x * x; + y = y * y; + x2 = 1.0; + y2 = 1.0; + f = 1.0; + rn = 0.0; + d = 0.0; + do { + rn += 1.0; + f *= rn; + rn += 1.0; + f *= rn; + x2 *= x; + y2 *= y; + t = y2 + x2; + t /= f; + d += t; + + rn += 1.0; + f *= rn; + rn += 1.0; + f *= rn; + x2 *= x; + y2 *= y; + t = y2 - x2; + t /= f; + d += t; + } while (fabs(t/d) > MACHEP); + return d; +} |