diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2001-05-10 00:40:28 +0000 |
commit | 1077fa4d772832f77a677ce7fb7c2d513b959e3f (patch) | |
tree | 579bee13fb0b58d2800206366ec2caecbb15f3fc /libm/double/k1.c | |
parent | 22358dd7ce7bb49792204b698f01a6f69b9c8e08 (diff) |
uClibc now has a math library. muahahahaha!
-Erik
Diffstat (limited to 'libm/double/k1.c')
-rw-r--r-- | libm/double/k1.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/libm/double/k1.c b/libm/double/k1.c new file mode 100644 index 000000000..a96305355 --- /dev/null +++ b/libm/double/k1.c @@ -0,0 +1,335 @@ +/* k1.c + * + * Modified Bessel function, third kind, order one + * + * + * + * SYNOPSIS: + * + * double x, y, k1(); + * + * y = k1( x ); + * + * + * + * DESCRIPTION: + * + * Computes the modified Bessel function of the third kind + * of order one of the argument. + * + * The range is partitioned into the two intervals [0,2] and + * (2, infinity). Chebyshev polynomial expansions are employed + * in each interval. + * + * + * + * ACCURACY: + * + * Relative error: + * arithmetic domain # trials peak rms + * DEC 0, 30 3300 8.9e-17 2.2e-17 + * IEEE 0, 30 30000 1.2e-15 1.6e-16 + * + * ERROR MESSAGES: + * + * message condition value returned + * k1 domain x <= 0 MAXNUM + * + */ +/* k1e.c + * + * Modified Bessel function, third kind, order one, + * exponentially scaled + * + * + * + * SYNOPSIS: + * + * double x, y, k1e(); + * + * y = k1e( x ); + * + * + * + * DESCRIPTION: + * + * Returns exponentially scaled modified Bessel function + * of the third kind of order one of the argument: + * + * k1e(x) = exp(x) * k1(x). + * + * + * + * ACCURACY: + * + * Relative error: + * arithmetic domain # trials peak rms + * IEEE 0, 30 30000 7.8e-16 1.2e-16 + * See k1(). + * + */ + +/* +Cephes Math Library Release 2.8: June, 2000 +Copyright 1984, 1987, 2000 by Stephen L. Moshier +*/ + +#include <math.h> + +/* Chebyshev coefficients for x(K1(x) - log(x/2) I1(x)) + * in the interval [0,2]. + * + * lim(x->0){ x(K1(x) - log(x/2) I1(x)) } = 1. + */ + +#ifdef UNK +static double A[] = +{ +-7.02386347938628759343E-18, +-2.42744985051936593393E-15, +-6.66690169419932900609E-13, +-1.41148839263352776110E-10, +-2.21338763073472585583E-8, +-2.43340614156596823496E-6, +-1.73028895751305206302E-4, +-6.97572385963986435018E-3, +-1.22611180822657148235E-1, +-3.53155960776544875667E-1, + 1.52530022733894777053E0 +}; +#endif + +#ifdef DEC +static unsigned short A[] = { +0122001,0110501,0164746,0151255, +0124056,0165213,0150034,0147377, +0126073,0124026,0167207,0001044, +0130033,0030735,0141061,0033116, +0131676,0020350,0121341,0107175, +0133443,0046631,0062031,0070716, +0135065,0067427,0026435,0164022, +0136344,0112234,0165752,0006222, +0137373,0015622,0017016,0155636, +0137664,0150333,0125730,0067240, +0040303,0036411,0130200,0043120 +}; +#endif + +#ifdef IBMPC +static unsigned short A[] = { +0xda56,0x3d3c,0x3228,0xbc60, +0x99e0,0x7a03,0xdd51,0xbce5, +0xe045,0xddd0,0x7502,0xbd67, +0x26ca,0xb846,0x663b,0xbde3, +0x31d0,0x145c,0xc41d,0xbe57, +0x2e3a,0x2c83,0x69b3,0xbec4, +0xbd02,0xe5a3,0xade2,0xbf26, +0x4192,0x9d7d,0x9293,0xbf7c, +0xdb74,0x43c1,0x6372,0xbfbf, +0x0dd4,0x757b,0x9a1b,0xbfd6, +0x08ca,0x3610,0x67a1,0x3ff8 +}; +#endif + +#ifdef MIEEE +static unsigned short A[] = { +0xbc60,0x3228,0x3d3c,0xda56, +0xbce5,0xdd51,0x7a03,0x99e0, +0xbd67,0x7502,0xddd0,0xe045, +0xbde3,0x663b,0xb846,0x26ca, +0xbe57,0xc41d,0x145c,0x31d0, +0xbec4,0x69b3,0x2c83,0x2e3a, +0xbf26,0xade2,0xe5a3,0xbd02, +0xbf7c,0x9293,0x9d7d,0x4192, +0xbfbf,0x6372,0x43c1,0xdb74, +0xbfd6,0x9a1b,0x757b,0x0dd4, +0x3ff8,0x67a1,0x3610,0x08ca +}; +#endif + + + +/* Chebyshev coefficients for exp(x) sqrt(x) K1(x) + * in the interval [2,infinity]. + * + * lim(x->inf){ exp(x) sqrt(x) K1(x) } = sqrt(pi/2). + */ + +#ifdef UNK +static double B[] = +{ +-5.75674448366501715755E-18, + 1.79405087314755922667E-17, +-5.68946255844285935196E-17, + 1.83809354436663880070E-16, +-6.05704724837331885336E-16, + 2.03870316562433424052E-15, +-7.01983709041831346144E-15, + 2.47715442448130437068E-14, +-8.97670518232499435011E-14, + 3.34841966607842919884E-13, +-1.28917396095102890680E-12, + 5.13963967348173025100E-12, +-2.12996783842756842877E-11, + 9.21831518760500529508E-11, +-4.19035475934189648750E-10, + 2.01504975519703286596E-9, +-1.03457624656780970260E-8, + 5.74108412545004946722E-8, +-3.50196060308781257119E-7, + 2.40648494783721712015E-6, +-1.93619797416608296024E-5, + 1.95215518471351631108E-4, +-2.85781685962277938680E-3, + 1.03923736576817238437E-1, + 2.72062619048444266945E0 +}; +#endif + +#ifdef DEC +static unsigned short B[] = { +0121724,0061352,0013041,0150076, +0022245,0074324,0016172,0173232, +0122603,0030250,0135670,0165221, +0023123,0165362,0023561,0060124, +0123456,0112436,0141654,0073623, +0024022,0163557,0077564,0006753, +0124374,0165221,0131014,0026524, +0024737,0017512,0144250,0175451, +0125312,0021456,0123136,0076633, +0025674,0077720,0020125,0102607, +0126265,0067543,0007744,0043701, +0026664,0152702,0033002,0074202, +0127273,0055234,0120016,0071733, +0027712,0133200,0042441,0075515, +0130346,0057000,0015456,0074470, +0031012,0074441,0051636,0111155, +0131461,0136444,0177417,0002101, +0032166,0111743,0032176,0021410, +0132674,0001224,0076555,0027060, +0033441,0077430,0135226,0106663, +0134242,0065610,0167155,0113447, +0035114,0131304,0043664,0102163, +0136073,0045065,0171465,0122123, +0037324,0152767,0147401,0017732, +0040456,0017275,0050061,0062120, +}; +#endif + +#ifdef IBMPC +static unsigned short B[] = { +0x3a08,0x42c4,0x8c5d,0xbc5a, +0x5ed3,0x838f,0xaf1a,0x3c74, +0x1d52,0x1777,0x6615,0xbc90, +0x2c0b,0x44ee,0x7d5e,0x3caa, +0x8ef2,0xd875,0xd2a3,0xbcc5, +0x81bd,0xefee,0x5ced,0x3ce2, +0x85ab,0x3641,0x9d52,0xbcff, +0x1f65,0x5915,0xe3e9,0x3d1b, +0xcfb3,0xd4cb,0x4465,0xbd39, +0xb0b1,0x040a,0x8ffa,0x3d57, +0x88f8,0x61fc,0xadec,0xbd76, +0x4f10,0x46c0,0x9ab8,0x3d96, +0xce7b,0x9401,0x6b53,0xbdb7, +0x2f6a,0x08a4,0x56d0,0x3dd9, +0xcf27,0x0365,0xcbc0,0xbdfc, +0xd24e,0x2a73,0x4f24,0x3e21, +0xe088,0x9fe1,0x37a4,0xbe46, +0xc461,0x668f,0xd27c,0x3e6e, +0xa5c6,0x8fad,0x8052,0xbe97, +0xd1b6,0x1752,0x2fe3,0x3ec4, +0xb2e5,0x1dcd,0x4d71,0xbef4, +0x908e,0x88f6,0x9658,0x3f29, +0xb48a,0xbe66,0x6946,0xbf67, +0x23fb,0xf9e0,0x9abe,0x3fba, +0x2c8a,0xaa06,0xc3d7,0x4005 +}; +#endif + +#ifdef MIEEE +static unsigned short B[] = { +0xbc5a,0x8c5d,0x42c4,0x3a08, +0x3c74,0xaf1a,0x838f,0x5ed3, +0xbc90,0x6615,0x1777,0x1d52, +0x3caa,0x7d5e,0x44ee,0x2c0b, +0xbcc5,0xd2a3,0xd875,0x8ef2, +0x3ce2,0x5ced,0xefee,0x81bd, +0xbcff,0x9d52,0x3641,0x85ab, +0x3d1b,0xe3e9,0x5915,0x1f65, +0xbd39,0x4465,0xd4cb,0xcfb3, +0x3d57,0x8ffa,0x040a,0xb0b1, +0xbd76,0xadec,0x61fc,0x88f8, +0x3d96,0x9ab8,0x46c0,0x4f10, +0xbdb7,0x6b53,0x9401,0xce7b, +0x3dd9,0x56d0,0x08a4,0x2f6a, +0xbdfc,0xcbc0,0x0365,0xcf27, +0x3e21,0x4f24,0x2a73,0xd24e, +0xbe46,0x37a4,0x9fe1,0xe088, +0x3e6e,0xd27c,0x668f,0xc461, +0xbe97,0x8052,0x8fad,0xa5c6, +0x3ec4,0x2fe3,0x1752,0xd1b6, +0xbef4,0x4d71,0x1dcd,0xb2e5, +0x3f29,0x9658,0x88f6,0x908e, +0xbf67,0x6946,0xbe66,0xb48a, +0x3fba,0x9abe,0xf9e0,0x23fb, +0x4005,0xc3d7,0xaa06,0x2c8a +}; +#endif + +#ifdef ANSIPROT +extern double chbevl ( double, void *, int ); +extern double exp ( double ); +extern double i1 ( double ); +extern double log ( double ); +extern double sqrt ( double ); +#else +double chbevl(), exp(), i1(), log(), sqrt(); +#endif +extern double PI; +extern double MINLOG, MAXNUM; + +double k1(x) +double x; +{ +double y, z; + +z = 0.5 * x; +if( z <= 0.0 ) + { + mtherr( "k1", DOMAIN ); + return( MAXNUM ); + } + +if( x <= 2.0 ) + { + y = x * x - 2.0; + y = log(z) * i1(x) + chbevl( y, A, 11 ) / x; + return( y ); + } + +return( exp(-x) * chbevl( 8.0/x - 2.0, B, 25 ) / sqrt(x) ); +} + + + + +double k1e( x ) +double x; +{ +double y; + +if( x <= 0.0 ) + { + mtherr( "k1e", DOMAIN ); + return( MAXNUM ); + } + +if( x <= 2.0 ) + { + y = x * x - 2.0; + y = log( 0.5 * x ) * i1(x) + chbevl( y, A, 11 ) / x; + return( y * exp(x) ); + } + +return( chbevl( 8.0/x - 2.0, B, 25 ) / sqrt(x) ); +} |