| Elliott Hughes | a0ee078 | 2013-01-30 19:06:37 -0800 | [diff] [blame] | 1 | /*- |
| 2 | * Copyright (c) 2011 David Schultz |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice unmodified, this list of conditions, and the following |
| 10 | * disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 25 | */ |
| 26 | |
| 27 | /* |
| 28 | * Hyperbolic tangent of a complex argument z. See s_ctanh.c for details. |
| 29 | */ |
| 30 | |
| 31 | #include <sys/cdefs.h> |
| 32 | __FBSDID("$FreeBSD$"); |
| 33 | |
| 34 | #include <complex.h> |
| 35 | #include <math.h> |
| 36 | |
| 37 | #include "math_private.h" |
| 38 | |
| 39 | float complex |
| 40 | ctanhf(float complex z) |
| 41 | { |
| 42 | float x, y; |
| 43 | float t, beta, s, rho, denom; |
| 44 | uint32_t hx, ix; |
| 45 | |
| 46 | x = crealf(z); |
| 47 | y = cimagf(z); |
| 48 | |
| 49 | GET_FLOAT_WORD(hx, x); |
| 50 | ix = hx & 0x7fffffff; |
| 51 | |
| 52 | if (ix >= 0x7f800000) { |
| 53 | if (ix & 0x7fffff) |
| 54 | return (cpackf(x, (y == 0 ? y : x * y))); |
| 55 | SET_FLOAT_WORD(x, hx - 0x40000000); |
| 56 | return (cpackf(x, |
| 57 | copysignf(0, isinf(y) ? y : sinf(y) * cosf(y)))); |
| 58 | } |
| 59 | |
| 60 | if (!isfinite(y)) |
| 61 | return (cpackf(y - y, y - y)); |
| 62 | |
| 63 | if (ix >= 0x41300000) { /* x >= 11 */ |
| 64 | float exp_mx = expf(-fabsf(x)); |
| 65 | return (cpackf(copysignf(1, x), |
| 66 | 4 * sinf(y) * cosf(y) * exp_mx * exp_mx)); |
| 67 | } |
| 68 | |
| 69 | t = tanf(y); |
| 70 | beta = 1.0 + t * t; |
| 71 | s = sinhf(x); |
| 72 | rho = sqrtf(1 + s * s); |
| 73 | denom = 1 + beta * s * s; |
| 74 | return (cpackf((beta * rho * s) / denom, t / denom)); |
| 75 | } |
| 76 | |
| 77 | float complex |
| 78 | ctanf(float complex z) |
| 79 | { |
| 80 | |
| 81 | z = ctanhf(cpackf(-cimagf(z), crealf(z))); |
| 82 | return (cpackf(cimagf(z), -crealf(z))); |
| 83 | } |
| 84 | |