| 1 | |
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| 2 | /* @(#)w_jn.c 5.1 93/09/24 */ |
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| 3 | /* |
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| 4 | * ==================================================== |
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| 5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 6 | * |
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| 7 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 8 | * Permission to use, copy, modify, and distribute this |
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| 9 | * software is freely granted, provided that this notice |
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| 10 | * is preserved. |
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| 11 | * ==================================================== |
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| 12 | */ |
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| 13 | |
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| 14 | /* |
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| 15 | * wrapper jn(int n, double x), yn(int n, double x) |
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| 16 | * floating point Bessel's function of the 1st and 2nd kind |
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| 17 | * of order n |
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| 18 | * |
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| 19 | * Special cases: |
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| 20 | * y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal; |
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| 21 | * y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal. |
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| 22 | * Note 2. About jn(n,x), yn(n,x) |
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| 23 | * For n=0, j0(x) is called, |
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| 24 | * for n=1, j1(x) is called, |
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| 25 | * for n<x, forward recursion us used starting |
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| 26 | * from values of j0(x) and j1(x). |
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| 27 | * for n>x, a continued fraction approximation to |
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| 28 | * j(n,x)/j(n-1,x) is evaluated and then backward |
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| 29 | * recursion is used starting from a supposed value |
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| 30 | * for j(n,x). The resulting value of j(0,x) is |
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| 31 | * compared with the actual value to correct the |
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| 32 | * supposed value of j(n,x). |
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| 33 | * |
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| 34 | * yn(n,x) is similar in all respects, except |
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| 35 | * that forward recursion is used for all |
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| 36 | * values of n>1. |
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| 37 | * |
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| 38 | */ |
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| 39 | |
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| 40 | #include "fdlibm.h" |
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| 41 | #include <errno.h> |
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| 42 | |
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| 43 | #ifndef _DOUBLE_IS_32BITS |
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| 44 | |
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| 45 | #ifdef __STDC__ |
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| 46 | double jn(int n, double x) /* wrapper jn */ |
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| 47 | #else |
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| 48 | double jn(n,x) /* wrapper jn */ |
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| 49 | double x; int n; |
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| 50 | #endif |
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| 51 | { |
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| 52 | #ifdef _IEEE_LIBM |
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| 53 | return __ieee754_jn(n,x); |
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| 54 | #else |
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| 55 | double z; |
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| 56 | struct exception exc; |
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| 57 | z = __ieee754_jn(n,x); |
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| 58 | if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; |
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| 59 | if(fabs(x)>X_TLOSS) { |
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| 60 | /* jn(|x|>X_TLOSS) */ |
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| 61 | exc.type = TLOSS; |
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| 62 | exc.name = "jn"; |
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| 63 | exc.err = 0; |
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| 64 | exc.arg1 = n; |
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| 65 | exc.arg2 = x; |
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| 66 | exc.retval = 0.0; |
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| 67 | if (_LIB_VERSION == _POSIX_) |
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| 68 | errno = ERANGE; |
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| 69 | else if (!matherr(&exc)) { |
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| 70 | errno = ERANGE; |
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| 71 | } |
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| 72 | if (exc.err != 0) |
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| 73 | errno = exc.err; |
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| 74 | return exc.retval; |
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| 75 | } else |
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| 76 | return z; |
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| 77 | #endif |
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| 78 | } |
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| 79 | |
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| 80 | #ifdef __STDC__ |
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| 81 | double yn(int n, double x) /* wrapper yn */ |
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| 82 | #else |
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| 83 | double yn(n,x) /* wrapper yn */ |
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| 84 | double x; int n; |
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| 85 | #endif |
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| 86 | { |
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| 87 | #ifdef _IEEE_LIBM |
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| 88 | return __ieee754_yn(n,x); |
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| 89 | #else |
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| 90 | double z; |
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| 91 | struct exception exc; |
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| 92 | z = __ieee754_yn(n,x); |
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| 93 | if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; |
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| 94 | if(x <= 0.0){ |
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| 95 | /* yn(n,0) = -inf or yn(x<0) = NaN */ |
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| 96 | #ifndef HUGE_VAL |
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| 97 | #define HUGE_VAL inf |
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| 98 | double inf = 0.0; |
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| 99 | |
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| 100 | SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ |
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| 101 | #endif |
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| 102 | exc.type = DOMAIN; /* should be SING for IEEE */ |
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| 103 | exc.name = "yn"; |
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| 104 | exc.err = 0; |
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| 105 | exc.arg1 = n; |
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| 106 | exc.arg2 = x; |
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| 107 | if (_LIB_VERSION == _SVID_) |
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| 108 | exc.retval = -HUGE; |
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| 109 | else |
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| 110 | exc.retval = -HUGE_VAL; |
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| 111 | if (_LIB_VERSION == _POSIX_) |
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| 112 | errno = EDOM; |
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| 113 | else if (!matherr(&exc)) { |
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| 114 | errno = EDOM; |
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| 115 | } |
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| 116 | if (exc.err != 0) |
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| 117 | errno = exc.err; |
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| 118 | return exc.retval; |
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| 119 | } |
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| 120 | if(x>X_TLOSS) { |
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| 121 | /* yn(x>X_TLOSS) */ |
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| 122 | exc.type = TLOSS; |
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| 123 | exc.name = "yn"; |
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| 124 | exc.err = 0; |
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| 125 | exc.arg1 = n; |
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| 126 | exc.arg2 = x; |
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| 127 | exc.retval = 0.0; |
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| 128 | if (_LIB_VERSION == _POSIX_) |
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| 129 | errno = ERANGE; |
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| 130 | else if (!matherr(&exc)) { |
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| 131 | errno = ERANGE; |
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| 132 | } |
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| 133 | if (exc.err != 0) |
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| 134 | errno = exc.err; |
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| 135 | return exc.retval; |
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| 136 | } else |
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| 137 | return z; |
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| 138 | #endif |
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| 139 | } |
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| 140 | |
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| 141 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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