71 lines
1.4 KiB
C
71 lines
1.4 KiB
C
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/* _LSinh function */
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#include "wctype.h"
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#include "xmath.h"
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_STD_BEGIN
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/* coefficients */
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#define NP (sizeof (p) / sizeof (p[0]) - 1)
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static const long double p[] = { /* courtesy Dr. Tim Prince */
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0.0000000000000028486835L,
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0.0000000000007646464279L,
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0.0000000001605905091647L,
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0.0000000250521083436962L,
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0.0000027557319224130455L,
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0.0001984126984126956009L,
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0.0083333333333333336073L,
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0.1666666666666666666564L,
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1.0000000000000000000001L};
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_CRTIMP2 long double __cdecl _LSinh(long double x, long double y)
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{ /* compute y*sinh(x), |y| <= 1 */
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switch (_LDtest(&x))
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{ /* test for special codes */
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case NAN:
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errno = EDOM;
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return (x);
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case INF:
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if (y == 0)
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return (0);
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errno = ERANGE;
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return (LSIGN(x) ? -_LInf._L : _LInf._L);
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case 0:
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return (0);
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default: /* finite */
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{ /* compute sinh(finite) */
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short neg;
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if (x < 0)
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x = -x, neg = 1;
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else
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neg = 0;
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if (x < _LRteps._L)
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x *= y; /* x tiny */
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else if (x < 1)
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{
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long double w = x * x;
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x += x * w * _LPoly(w, p, NP - 1);
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x *= y;
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}
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else if (x < _LXbig)
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{ /* worth adding in exp(-x) */
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_LExp(&x, 1, -1);
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x = y * (x - 0.25 / x);
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}
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else if (0 <= _LExp(&x, y, -1))
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errno = ERANGE; /* x large */
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return (neg ? -x : x);
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}
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}
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}
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_STD_END
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/*
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* Copyright (c) 1994 by P.J. Plauger. ALL RIGHTS RESERVED.
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* Consult your license regarding permissions and restrictions.
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*/
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/*
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941029 pjp: added _STD machinery
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*/
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