Last change
on this file since 351 was 337, checked in by coas-nagasima, 6 years ago |
ASP3版ECNLを追加
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Property svn:eol-style
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native
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Property svn:mime-type
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File size:
837 bytes
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1 | #include "libm.h"
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2 |
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3 | /* sinh(x) = (exp(x) - 1/exp(x))/2
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4 | * = (exp(x)-1 + (exp(x)-1)/exp(x))/2
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5 | * = x + x^3/6 + o(x^5)
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6 | */
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7 | double sinh(double x)
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8 | {
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9 | union {double f; uint64_t i;} u = {.f = x};
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10 | uint32_t w;
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11 | double t, h, absx;
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12 |
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13 | h = 0.5;
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14 | if (u.i >> 63)
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15 | h = -h;
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16 | /* |x| */
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17 | u.i &= (uint64_t)-1/2;
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18 | absx = u.f;
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19 | w = u.i >> 32;
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20 |
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21 | /* |x| < log(DBL_MAX) */
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22 | if (w < 0x40862e42) {
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23 | t = expm1(absx);
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24 | if (w < 0x3ff00000) {
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25 | if (w < 0x3ff00000 - (26<<20))
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26 | /* note: inexact and underflow are raised by expm1 */
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27 | /* note: this branch avoids spurious underflow */
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28 | return x;
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29 | return h*(2*t - t*t/(t+1));
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30 | }
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31 | /* note: |x|>log(0x1p26)+eps could be just h*exp(x) */
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32 | return h*(t + t/(t+1));
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33 | }
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34 |
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35 | /* |x| > log(DBL_MAX) or nan */
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36 | /* note: the result is stored to handle overflow */
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37 | t = 2*h*__expo2(absx);
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38 | return t;
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39 | }
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