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0001 // This file is part of Eigen, a lightweight C++ template library
0002 // for linear algebra.
0003 //
0004 // Copyright (C) 2015 Eugene Brevdo <ebrevdo@gmail.com>
0005 //
0006 // This Source Code Form is subject to the terms of the Mozilla
0007 // Public License v. 2.0. If a copy of the MPL was not distributed
0008 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
0009 
0010 #ifndef EIGEN_BESSEL_FUNCTIONS_H
0011 #define EIGEN_BESSEL_FUNCTIONS_H
0012 
0013 namespace Eigen {
0014 namespace internal {
0015 
0016 //  Parts of this code are based on the Cephes Math Library.
0017 //
0018 //  Cephes Math Library Release 2.8:  June, 2000
0019 //  Copyright 1984, 1987, 1992, 2000 by Stephen L. Moshier
0020 //
0021 //  Permission has been kindly provided by the original author
0022 //  to incorporate the Cephes software into the Eigen codebase:
0023 //
0024 //    From: Stephen Moshier
0025 //    To: Eugene Brevdo
0026 //    Subject: Re: Permission to wrap several cephes functions in Eigen
0027 //
0028 //    Hello Eugene,
0029 //
0030 //    Thank you for writing.
0031 //
0032 //    If your licensing is similar to BSD, the formal way that has been
0033 //    handled is simply to add a statement to the effect that you are incorporating
0034 //    the Cephes software by permission of the author.
0035 //
0036 //    Good luck with your project,
0037 //    Steve
0038 
0039 
0040 /****************************************************************************
0041  * Implementation of Bessel function, based on Cephes                       *
0042  ****************************************************************************/
0043 
0044 template <typename Scalar>
0045 struct bessel_i0e_retval {
0046   typedef Scalar type;
0047 };
0048 
0049 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0050 struct generic_i0e {
0051   EIGEN_DEVICE_FUNC
0052   static EIGEN_STRONG_INLINE T run(const T&) {
0053     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0054                         THIS_TYPE_IS_NOT_SUPPORTED);
0055     return ScalarType(0);
0056   }
0057 };
0058 
0059 template <typename T>
0060 struct generic_i0e<T, float> {
0061   EIGEN_DEVICE_FUNC
0062   static EIGEN_STRONG_INLINE T run(const T& x) {
0063     /*  i0ef.c
0064      *
0065      *  Modified Bessel function of order zero,
0066      *  exponentially scaled
0067      *
0068      *
0069      *
0070      * SYNOPSIS:
0071      *
0072      * float x, y, i0ef();
0073      *
0074      * y = i0ef( x );
0075      *
0076      *
0077      *
0078      * DESCRIPTION:
0079      *
0080      * Returns exponentially scaled modified Bessel function
0081      * of order zero of the argument.
0082      *
0083      * The function is defined as i0e(x) = exp(-|x|) j0( ix ).
0084      *
0085      *
0086      *
0087      * ACCURACY:
0088      *
0089      *                      Relative error:
0090      * arithmetic   domain     # trials      peak         rms
0091      *    IEEE      0,30        100000      3.7e-7      7.0e-8
0092      * See i0f().
0093      *
0094      */
0095 
0096     const float A[] = {-1.30002500998624804212E-8f, 6.04699502254191894932E-8f,
0097                        -2.67079385394061173391E-7f, 1.11738753912010371815E-6f,
0098                        -4.41673835845875056359E-6f, 1.64484480707288970893E-5f,
0099                        -5.75419501008210370398E-5f, 1.88502885095841655729E-4f,
0100                        -5.76375574538582365885E-4f, 1.63947561694133579842E-3f,
0101                        -4.32430999505057594430E-3f, 1.05464603945949983183E-2f,
0102                        -2.37374148058994688156E-2f, 4.93052842396707084878E-2f,
0103                        -9.49010970480476444210E-2f, 1.71620901522208775349E-1f,
0104                        -3.04682672343198398683E-1f, 6.76795274409476084995E-1f};
0105 
0106     const float B[] = {3.39623202570838634515E-9f, 2.26666899049817806459E-8f,
0107                        2.04891858946906374183E-7f, 2.89137052083475648297E-6f,
0108                        6.88975834691682398426E-5f, 3.36911647825569408990E-3f,
0109                        8.04490411014108831608E-1f};
0110     T y = pabs(x);
0111     T y_le_eight = internal::pchebevl<T, 18>::run(
0112         pmadd(pset1<T>(0.5f), y, pset1<T>(-2.0f)), A);
0113     T y_gt_eight = pmul(
0114         internal::pchebevl<T, 7>::run(
0115             psub(pdiv(pset1<T>(32.0f), y), pset1<T>(2.0f)), B),
0116         prsqrt(y));
0117     // TODO: Perhaps instead check whether all packet elements are in
0118     // [-8, 8] and evaluate a branch based off of that. It's possible
0119     // in practice most elements are in this region.
0120     return pselect(pcmp_le(y, pset1<T>(8.0f)), y_le_eight, y_gt_eight);
0121   }
0122 };
0123 
0124 template <typename T>
0125 struct generic_i0e<T, double> {
0126   EIGEN_DEVICE_FUNC
0127   static EIGEN_STRONG_INLINE T run(const T& x) {
0128     /*  i0e.c
0129      *
0130      *  Modified Bessel function of order zero,
0131      *  exponentially scaled
0132      *
0133      *
0134      *
0135      * SYNOPSIS:
0136      *
0137      * double x, y, i0e();
0138      *
0139      * y = i0e( x );
0140      *
0141      *
0142      *
0143      * DESCRIPTION:
0144      *
0145      * Returns exponentially scaled modified Bessel function
0146      * of order zero of the argument.
0147      *
0148      * The function is defined as i0e(x) = exp(-|x|) j0( ix ).
0149      *
0150      *
0151      *
0152      * ACCURACY:
0153      *
0154      *                      Relative error:
0155      * arithmetic   domain     # trials      peak         rms
0156      *    IEEE      0,30        30000       5.4e-16     1.2e-16
0157      * See i0().
0158      *
0159      */
0160 
0161     const double A[] = {-4.41534164647933937950E-18, 3.33079451882223809783E-17,
0162                         -2.43127984654795469359E-16, 1.71539128555513303061E-15,
0163                         -1.16853328779934516808E-14, 7.67618549860493561688E-14,
0164                         -4.85644678311192946090E-13, 2.95505266312963983461E-12,
0165                         -1.72682629144155570723E-11, 9.67580903537323691224E-11,
0166                         -5.18979560163526290666E-10, 2.65982372468238665035E-9,
0167                         -1.30002500998624804212E-8,  6.04699502254191894932E-8,
0168                         -2.67079385394061173391E-7,  1.11738753912010371815E-6,
0169                         -4.41673835845875056359E-6,  1.64484480707288970893E-5,
0170                         -5.75419501008210370398E-5,  1.88502885095841655729E-4,
0171                         -5.76375574538582365885E-4,  1.63947561694133579842E-3,
0172                         -4.32430999505057594430E-3,  1.05464603945949983183E-2,
0173                         -2.37374148058994688156E-2,  4.93052842396707084878E-2,
0174                         -9.49010970480476444210E-2,  1.71620901522208775349E-1,
0175                         -3.04682672343198398683E-1,  6.76795274409476084995E-1};
0176     const double B[] = {
0177         -7.23318048787475395456E-18, -4.83050448594418207126E-18,
0178         4.46562142029675999901E-17,  3.46122286769746109310E-17,
0179         -2.82762398051658348494E-16, -3.42548561967721913462E-16,
0180         1.77256013305652638360E-15,  3.81168066935262242075E-15,
0181         -9.55484669882830764870E-15, -4.15056934728722208663E-14,
0182         1.54008621752140982691E-14,  3.85277838274214270114E-13,
0183         7.18012445138366623367E-13,  -1.79417853150680611778E-12,
0184         -1.32158118404477131188E-11, -3.14991652796324136454E-11,
0185         1.18891471078464383424E-11,  4.94060238822496958910E-10,
0186         3.39623202570838634515E-9,   2.26666899049817806459E-8,
0187         2.04891858946906374183E-7,   2.89137052083475648297E-6,
0188         6.88975834691682398426E-5,   3.36911647825569408990E-3,
0189         8.04490411014108831608E-1};
0190     T y = pabs(x);
0191     T y_le_eight = internal::pchebevl<T, 30>::run(
0192         pmadd(pset1<T>(0.5), y, pset1<T>(-2.0)), A);
0193     T y_gt_eight = pmul(
0194         internal::pchebevl<T, 25>::run(
0195             psub(pdiv(pset1<T>(32.0), y), pset1<T>(2.0)), B),
0196         prsqrt(y));
0197     // TODO: Perhaps instead check whether all packet elements are in
0198     // [-8, 8] and evaluate a branch based off of that. It's possible
0199     // in practice most elements are in this region.
0200     return pselect(pcmp_le(y, pset1<T>(8.0)), y_le_eight, y_gt_eight);
0201   }
0202 };
0203 
0204 template <typename T>
0205 struct bessel_i0e_impl {
0206   EIGEN_DEVICE_FUNC
0207   static EIGEN_STRONG_INLINE T run(const T x) {
0208     return generic_i0e<T>::run(x);
0209   }
0210 };
0211 
0212 template <typename Scalar>
0213 struct bessel_i0_retval {
0214   typedef Scalar type;
0215 };
0216 
0217 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0218 struct generic_i0 {
0219   EIGEN_DEVICE_FUNC
0220   static EIGEN_STRONG_INLINE T run(const T& x) {
0221     return pmul(
0222         pexp(pabs(x)),
0223         generic_i0e<T, ScalarType>::run(x));
0224   }
0225 };
0226 
0227 template <typename T>
0228 struct bessel_i0_impl {
0229   EIGEN_DEVICE_FUNC
0230   static EIGEN_STRONG_INLINE T run(const T x) {
0231     return generic_i0<T>::run(x);
0232   }
0233 };
0234 
0235 template <typename Scalar>
0236 struct bessel_i1e_retval {
0237   typedef Scalar type;
0238 };
0239 
0240 template <typename T, typename ScalarType = typename unpacket_traits<T>::type >
0241 struct generic_i1e {
0242   EIGEN_DEVICE_FUNC
0243   static EIGEN_STRONG_INLINE T run(const T&) {
0244     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0245                         THIS_TYPE_IS_NOT_SUPPORTED);
0246     return ScalarType(0);
0247   }
0248 };
0249 
0250 template <typename T>
0251 struct generic_i1e<T, float> {
0252   EIGEN_DEVICE_FUNC
0253   static EIGEN_STRONG_INLINE T run(const T& x) {
0254     /* i1ef.c
0255      *
0256      *  Modified Bessel function of order one,
0257      *  exponentially scaled
0258      *
0259      *
0260      *
0261      * SYNOPSIS:
0262      *
0263      * float x, y, i1ef();
0264      *
0265      * y = i1ef( x );
0266      *
0267      *
0268      *
0269      * DESCRIPTION:
0270      *
0271      * Returns exponentially scaled modified Bessel function
0272      * of order one of the argument.
0273      *
0274      * The function is defined as i1(x) = -i exp(-|x|) j1( ix ).
0275      *
0276      *
0277      *
0278      * ACCURACY:
0279      *
0280      *                      Relative error:
0281      * arithmetic   domain     # trials      peak         rms
0282      *    IEEE      0, 30       30000       1.5e-6      1.5e-7
0283      * See i1().
0284      *
0285      */
0286     const float A[] = {9.38153738649577178388E-9f, -4.44505912879632808065E-8f,
0287                        2.00329475355213526229E-7f, -8.56872026469545474066E-7f,
0288                        3.47025130813767847674E-6f, -1.32731636560394358279E-5f,
0289                        4.78156510755005422638E-5f, -1.61760815825896745588E-4f,
0290                        5.12285956168575772895E-4f, -1.51357245063125314899E-3f,
0291                        4.15642294431288815669E-3f, -1.05640848946261981558E-2f,
0292                        2.47264490306265168283E-2f, -5.29459812080949914269E-2f,
0293                        1.02643658689847095384E-1f, -1.76416518357834055153E-1f,
0294                        2.52587186443633654823E-1f};
0295 
0296     const float B[] = {-3.83538038596423702205E-9f, -2.63146884688951950684E-8f,
0297                        -2.51223623787020892529E-7f, -3.88256480887769039346E-6f,
0298                        -1.10588938762623716291E-4f, -9.76109749136146840777E-3f,
0299                        7.78576235018280120474E-1f};
0300 
0301 
0302     T y = pabs(x);
0303     T y_le_eight = pmul(y, internal::pchebevl<T, 17>::run(
0304         pmadd(pset1<T>(0.5f), y, pset1<T>(-2.0f)), A));
0305     T y_gt_eight = pmul(
0306         internal::pchebevl<T, 7>::run(
0307             psub(pdiv(pset1<T>(32.0f), y),
0308                  pset1<T>(2.0f)), B),
0309         prsqrt(y));
0310     // TODO: Perhaps instead check whether all packet elements are in
0311     // [-8, 8] and evaluate a branch based off of that. It's possible
0312     // in practice most elements are in this region.
0313     y = pselect(pcmp_le(y, pset1<T>(8.0f)), y_le_eight, y_gt_eight);
0314     return pselect(pcmp_lt(x, pset1<T>(0.0f)), pnegate(y), y);
0315   }
0316 };
0317 
0318 template <typename T>
0319 struct generic_i1e<T, double> {
0320   EIGEN_DEVICE_FUNC
0321   static EIGEN_STRONG_INLINE T run(const T& x) {
0322     /*  i1e.c
0323      *
0324      *  Modified Bessel function of order one,
0325      *  exponentially scaled
0326      *
0327      *
0328      *
0329      * SYNOPSIS:
0330      *
0331      * double x, y, i1e();
0332      *
0333      * y = i1e( x );
0334      *
0335      *
0336      *
0337      * DESCRIPTION:
0338      *
0339      * Returns exponentially scaled modified Bessel function
0340      * of order one of the argument.
0341      *
0342      * The function is defined as i1(x) = -i exp(-|x|) j1( ix ).
0343      *
0344      *
0345      *
0346      * ACCURACY:
0347      *
0348      *                      Relative error:
0349      * arithmetic   domain     # trials      peak         rms
0350      *    IEEE      0, 30       30000       2.0e-15     2.0e-16
0351      * See i1().
0352      *
0353      */
0354     const double A[] = {2.77791411276104639959E-18, -2.11142121435816608115E-17,
0355                         1.55363195773620046921E-16, -1.10559694773538630805E-15,
0356                         7.60068429473540693410E-15, -5.04218550472791168711E-14,
0357                         3.22379336594557470981E-13, -1.98397439776494371520E-12,
0358                         1.17361862988909016308E-11, -6.66348972350202774223E-11,
0359                         3.62559028155211703701E-10, -1.88724975172282928790E-9,
0360                         9.38153738649577178388E-9,  -4.44505912879632808065E-8,
0361                         2.00329475355213526229E-7,  -8.56872026469545474066E-7,
0362                         3.47025130813767847674E-6,  -1.32731636560394358279E-5,
0363                         4.78156510755005422638E-5,  -1.61760815825896745588E-4,
0364                         5.12285956168575772895E-4,  -1.51357245063125314899E-3,
0365                         4.15642294431288815669E-3,  -1.05640848946261981558E-2,
0366                         2.47264490306265168283E-2,  -5.29459812080949914269E-2,
0367                         1.02643658689847095384E-1,  -1.76416518357834055153E-1,
0368                         2.52587186443633654823E-1};
0369     const double B[] = {
0370         7.51729631084210481353E-18,  4.41434832307170791151E-18,
0371         -4.65030536848935832153E-17, -3.20952592199342395980E-17,
0372         2.96262899764595013876E-16,  3.30820231092092828324E-16,
0373         -1.88035477551078244854E-15, -3.81440307243700780478E-15,
0374         1.04202769841288027642E-14,  4.27244001671195135429E-14,
0375         -2.10154184277266431302E-14, -4.08355111109219731823E-13,
0376         -7.19855177624590851209E-13, 2.03562854414708950722E-12,
0377         1.41258074366137813316E-11,  3.25260358301548823856E-11,
0378         -1.89749581235054123450E-11, -5.58974346219658380687E-10,
0379         -3.83538038596423702205E-9,  -2.63146884688951950684E-8,
0380         -2.51223623787020892529E-7,  -3.88256480887769039346E-6,
0381         -1.10588938762623716291E-4,  -9.76109749136146840777E-3,
0382         7.78576235018280120474E-1};
0383     T y = pabs(x);
0384     T y_le_eight = pmul(y, internal::pchebevl<T, 29>::run(
0385         pmadd(pset1<T>(0.5), y, pset1<T>(-2.0)), A));
0386     T y_gt_eight = pmul(
0387         internal::pchebevl<T, 25>::run(
0388             psub(pdiv(pset1<T>(32.0), y),
0389                  pset1<T>(2.0)), B),
0390         prsqrt(y));
0391     // TODO: Perhaps instead check whether all packet elements are in
0392     // [-8, 8] and evaluate a branch based off of that. It's possible
0393     // in practice most elements are in this region.
0394     y = pselect(pcmp_le(y, pset1<T>(8.0)), y_le_eight, y_gt_eight);
0395     return pselect(pcmp_lt(x, pset1<T>(0.0)), pnegate(y), y);
0396   }
0397 };
0398 
0399 template <typename T>
0400 struct bessel_i1e_impl {
0401   EIGEN_DEVICE_FUNC
0402   static EIGEN_STRONG_INLINE T run(const T x) {
0403     return generic_i1e<T>::run(x);
0404   }
0405 };
0406 
0407 template <typename T>
0408 struct bessel_i1_retval {
0409   typedef T type;
0410 };
0411 
0412 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0413 struct generic_i1 {
0414   EIGEN_DEVICE_FUNC
0415   static EIGEN_STRONG_INLINE T run(const T& x) {
0416     return pmul(
0417         pexp(pabs(x)),
0418         generic_i1e<T, ScalarType>::run(x));
0419   }
0420 };
0421 
0422 template <typename T>
0423 struct bessel_i1_impl {
0424   EIGEN_DEVICE_FUNC
0425   static EIGEN_STRONG_INLINE T run(const T x) {
0426     return generic_i1<T>::run(x);
0427   }
0428 };
0429 
0430 template <typename T>
0431 struct bessel_k0e_retval {
0432   typedef T type;
0433 };
0434 
0435 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0436 struct generic_k0e {
0437   EIGEN_DEVICE_FUNC
0438   static EIGEN_STRONG_INLINE T run(const T&) {
0439     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0440                         THIS_TYPE_IS_NOT_SUPPORTED);
0441     return ScalarType(0);
0442   }
0443 };
0444 
0445 template <typename T>
0446 struct generic_k0e<T, float> {
0447   EIGEN_DEVICE_FUNC
0448   static EIGEN_STRONG_INLINE T run(const T& x) {
0449     /*  k0ef.c
0450      *  Modified Bessel function, third kind, order zero,
0451      *  exponentially scaled
0452      *
0453      *
0454      *
0455      * SYNOPSIS:
0456      *
0457      * float x, y, k0ef();
0458      *
0459      * y = k0ef( x );
0460      *
0461      *
0462      *
0463      * DESCRIPTION:
0464      *
0465      * Returns exponentially scaled modified Bessel function
0466      * of the third kind of order zero of the argument.
0467      *
0468      *
0469      *
0470      * ACCURACY:
0471      *
0472      *                      Relative error:
0473      * arithmetic   domain     # trials      peak         rms
0474      *    IEEE      0, 30       30000       8.1e-7      7.8e-8
0475      * See k0().
0476      *
0477      */
0478 
0479     const float A[] = {1.90451637722020886025E-9f, 2.53479107902614945675E-7f,
0480                        2.28621210311945178607E-5f, 1.26461541144692592338E-3f,
0481                        3.59799365153615016266E-2f, 3.44289899924628486886E-1f,
0482                        -5.35327393233902768720E-1f};
0483 
0484     const float B[] = {-1.69753450938905987466E-9f, 8.57403401741422608519E-9f,
0485                        -4.66048989768794782956E-8f, 2.76681363944501510342E-7f,
0486                        -1.83175552271911948767E-6f, 1.39498137188764993662E-5f,
0487                        -1.28495495816278026384E-4f, 1.56988388573005337491E-3f,
0488                        -3.14481013119645005427E-2f, 2.44030308206595545468E0f};
0489     const T MAXNUM = pset1<T>(NumTraits<float>::infinity());
0490     const T two = pset1<T>(2.0);
0491     T x_le_two = internal::pchebevl<T, 7>::run(
0492         pmadd(x, x, pset1<T>(-2.0)), A);
0493     x_le_two = pmadd(
0494         generic_i0<T, float>::run(x), pnegate(
0495             plog(pmul(pset1<T>(0.5), x))), x_le_two);
0496     x_le_two = pmul(pexp(x), x_le_two);
0497     T x_gt_two = pmul(
0498             internal::pchebevl<T, 10>::run(
0499                 psub(pdiv(pset1<T>(8.0), x), two), B),
0500             prsqrt(x));
0501     return pselect(
0502         pcmp_le(x, pset1<T>(0.0)),
0503         MAXNUM,
0504         pselect(pcmp_le(x, two), x_le_two, x_gt_two));
0505   }
0506 };
0507 
0508 template <typename T>
0509 struct generic_k0e<T, double> {
0510   EIGEN_DEVICE_FUNC
0511   static EIGEN_STRONG_INLINE T run(const T& x) {
0512     /*  k0e.c
0513      *  Modified Bessel function, third kind, order zero,
0514      *  exponentially scaled
0515      *
0516      *
0517      *
0518      * SYNOPSIS:
0519      *
0520      * double x, y, k0e();
0521      *
0522      * y = k0e( x );
0523      *
0524      *
0525      *
0526      * DESCRIPTION:
0527      *
0528      * Returns exponentially scaled modified Bessel function
0529      * of the third kind of order zero of the argument.
0530      *
0531      *
0532      *
0533      * ACCURACY:
0534      *
0535      *                      Relative error:
0536      * arithmetic   domain     # trials      peak         rms
0537      *    IEEE      0, 30       30000       1.4e-15     1.4e-16
0538      * See k0().
0539      *
0540      */
0541 
0542     const double A[] = {
0543       1.37446543561352307156E-16,
0544       4.25981614279661018399E-14,
0545       1.03496952576338420167E-11,
0546       1.90451637722020886025E-9,
0547       2.53479107902614945675E-7,
0548       2.28621210311945178607E-5,
0549       1.26461541144692592338E-3,
0550       3.59799365153615016266E-2,
0551       3.44289899924628486886E-1,
0552       -5.35327393233902768720E-1};
0553     const double B[] = {
0554        5.30043377268626276149E-18, -1.64758043015242134646E-17,
0555        5.21039150503902756861E-17, -1.67823109680541210385E-16,
0556        5.51205597852431940784E-16, -1.84859337734377901440E-15,
0557        6.34007647740507060557E-15, -2.22751332699166985548E-14,
0558        8.03289077536357521100E-14, -2.98009692317273043925E-13,
0559        1.14034058820847496303E-12, -4.51459788337394416547E-12,
0560        1.85594911495471785253E-11, -7.95748924447710747776E-11,
0561        3.57739728140030116597E-10, -1.69753450938905987466E-9,
0562        8.57403401741422608519E-9, -4.66048989768794782956E-8,
0563        2.76681363944501510342E-7, -1.83175552271911948767E-6,
0564        1.39498137188764993662E-5, -1.28495495816278026384E-4,
0565        1.56988388573005337491E-3, -3.14481013119645005427E-2,
0566        2.44030308206595545468E0
0567     };
0568     const T MAXNUM = pset1<T>(NumTraits<double>::infinity());
0569     const T two = pset1<T>(2.0);
0570     T x_le_two = internal::pchebevl<T, 10>::run(
0571         pmadd(x, x, pset1<T>(-2.0)), A);
0572     x_le_two = pmadd(
0573         generic_i0<T, double>::run(x), pmul(
0574             pset1<T>(-1.0), plog(pmul(pset1<T>(0.5), x))), x_le_two);
0575     x_le_two = pmul(pexp(x), x_le_two);
0576     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0577     T x_gt_two = pmul(
0578             internal::pchebevl<T, 25>::run(
0579                 psub(pdiv(pset1<T>(8.0), x), two), B),
0580             prsqrt(x));
0581     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
0582   }
0583 };
0584 
0585 template <typename T>
0586 struct bessel_k0e_impl {
0587   EIGEN_DEVICE_FUNC
0588   static EIGEN_STRONG_INLINE T run(const T x) {
0589     return generic_k0e<T>::run(x);
0590   }
0591 };
0592 
0593 template <typename T>
0594 struct bessel_k0_retval {
0595   typedef T type;
0596 };
0597 
0598 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0599 struct generic_k0 {
0600   EIGEN_DEVICE_FUNC
0601   static EIGEN_STRONG_INLINE T run(const T&) {
0602     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0603                         THIS_TYPE_IS_NOT_SUPPORTED);
0604     return ScalarType(0);
0605   }
0606 };
0607 
0608 template <typename T>
0609 struct generic_k0<T, float> {
0610   EIGEN_DEVICE_FUNC
0611   static EIGEN_STRONG_INLINE T run(const T& x) {
0612     /*  k0f.c
0613      *  Modified Bessel function, third kind, order zero
0614      *
0615      *
0616      *
0617      * SYNOPSIS:
0618      *
0619      * float x, y, k0f();
0620      *
0621      * y = k0f( x );
0622      *
0623      *
0624      *
0625      * DESCRIPTION:
0626      *
0627      * Returns modified Bessel function of the third kind
0628      * of order zero of the argument.
0629      *
0630      * The range is partitioned into the two intervals [0,8] and
0631      * (8, infinity).  Chebyshev polynomial expansions are employed
0632      * in each interval.
0633      *
0634      *
0635      *
0636      * ACCURACY:
0637      *
0638      * Tested at 2000 random points between 0 and 8.  Peak absolute
0639      * error (relative when K0 > 1) was 1.46e-14; rms, 4.26e-15.
0640      *                      Relative error:
0641      * arithmetic   domain     # trials      peak         rms
0642      *    IEEE      0, 30       30000       7.8e-7      8.5e-8
0643      *
0644      * ERROR MESSAGES:
0645      *
0646      *   message         condition      value returned
0647      *  K0 domain          x <= 0          MAXNUM
0648      *
0649      */
0650 
0651     const float A[] = {1.90451637722020886025E-9f, 2.53479107902614945675E-7f,
0652                        2.28621210311945178607E-5f, 1.26461541144692592338E-3f,
0653                        3.59799365153615016266E-2f, 3.44289899924628486886E-1f,
0654                        -5.35327393233902768720E-1f};
0655 
0656     const float B[] = {-1.69753450938905987466E-9f, 8.57403401741422608519E-9f,
0657                        -4.66048989768794782956E-8f, 2.76681363944501510342E-7f,
0658                        -1.83175552271911948767E-6f, 1.39498137188764993662E-5f,
0659                        -1.28495495816278026384E-4f, 1.56988388573005337491E-3f,
0660                        -3.14481013119645005427E-2f, 2.44030308206595545468E0f};
0661     const T MAXNUM = pset1<T>(NumTraits<float>::infinity());
0662     const T two = pset1<T>(2.0);
0663     T x_le_two = internal::pchebevl<T, 7>::run(
0664         pmadd(x, x, pset1<T>(-2.0)), A);
0665     x_le_two = pmadd(
0666         generic_i0<T, float>::run(x), pnegate(
0667             plog(pmul(pset1<T>(0.5), x))), x_le_two);
0668     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0669     T x_gt_two = pmul(
0670         pmul(
0671             pexp(pnegate(x)),
0672             internal::pchebevl<T, 10>::run(
0673                 psub(pdiv(pset1<T>(8.0), x), two), B)),
0674         prsqrt(x));
0675     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
0676   }
0677 };
0678 
0679 template <typename T>
0680 struct generic_k0<T, double> {
0681   EIGEN_DEVICE_FUNC
0682   static EIGEN_STRONG_INLINE T run(const T& x) {
0683     /*
0684      *
0685      *  Modified Bessel function, third kind, order zero,
0686      *  exponentially scaled
0687      *
0688      *
0689      *
0690      * SYNOPSIS:
0691      *
0692      * double x, y, k0();
0693      *
0694      * y = k0( x );
0695      *
0696      *
0697      *
0698      * DESCRIPTION:
0699      *
0700      * Returns exponentially scaled modified Bessel function
0701      * of the third kind of order zero of the argument.
0702      *
0703      *
0704      *
0705      * ACCURACY:
0706      *
0707      *                      Relative error:
0708      * arithmetic   domain     # trials      peak         rms
0709      *    IEEE      0, 30       30000       1.4e-15     1.4e-16
0710      * See k0().
0711      *
0712      */
0713     const double A[] = {
0714       1.37446543561352307156E-16,
0715       4.25981614279661018399E-14,
0716       1.03496952576338420167E-11,
0717       1.90451637722020886025E-9,
0718       2.53479107902614945675E-7,
0719       2.28621210311945178607E-5,
0720       1.26461541144692592338E-3,
0721       3.59799365153615016266E-2,
0722       3.44289899924628486886E-1,
0723       -5.35327393233902768720E-1};
0724     const double B[] = {
0725        5.30043377268626276149E-18, -1.64758043015242134646E-17,
0726        5.21039150503902756861E-17, -1.67823109680541210385E-16,
0727        5.51205597852431940784E-16, -1.84859337734377901440E-15,
0728        6.34007647740507060557E-15, -2.22751332699166985548E-14,
0729        8.03289077536357521100E-14, -2.98009692317273043925E-13,
0730        1.14034058820847496303E-12, -4.51459788337394416547E-12,
0731        1.85594911495471785253E-11, -7.95748924447710747776E-11,
0732        3.57739728140030116597E-10, -1.69753450938905987466E-9,
0733        8.57403401741422608519E-9, -4.66048989768794782956E-8,
0734        2.76681363944501510342E-7, -1.83175552271911948767E-6,
0735        1.39498137188764993662E-5, -1.28495495816278026384E-4,
0736        1.56988388573005337491E-3, -3.14481013119645005427E-2,
0737        2.44030308206595545468E0
0738     };
0739     const T MAXNUM = pset1<T>(NumTraits<double>::infinity());
0740     const T two = pset1<T>(2.0);
0741     T x_le_two = internal::pchebevl<T, 10>::run(
0742         pmadd(x, x, pset1<T>(-2.0)), A);
0743     x_le_two = pmadd(
0744         generic_i0<T, double>::run(x), pnegate(
0745             plog(pmul(pset1<T>(0.5), x))), x_le_two);
0746     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0747     T x_gt_two = pmul(
0748         pmul(
0749             pexp(-x),
0750             internal::pchebevl<T, 25>::run(
0751                 psub(pdiv(pset1<T>(8.0), x), two), B)),
0752         prsqrt(x));
0753     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
0754   }
0755 };
0756 
0757 template <typename T>
0758 struct bessel_k0_impl {
0759   EIGEN_DEVICE_FUNC
0760   static EIGEN_STRONG_INLINE T run(const T x) {
0761     return generic_k0<T>::run(x);
0762   }
0763 };
0764 
0765 template <typename T>
0766 struct bessel_k1e_retval {
0767   typedef T type;
0768 };
0769 
0770 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0771 struct generic_k1e {
0772   EIGEN_DEVICE_FUNC
0773   static EIGEN_STRONG_INLINE T run(const T&) {
0774     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0775                         THIS_TYPE_IS_NOT_SUPPORTED);
0776     return ScalarType(0);
0777   }
0778 };
0779 
0780 template <typename T>
0781 struct generic_k1e<T, float> {
0782   EIGEN_DEVICE_FUNC
0783   static EIGEN_STRONG_INLINE T run(const T& x) {
0784     /* k1ef.c
0785      *
0786      *  Modified Bessel function, third kind, order one,
0787      *  exponentially scaled
0788      *
0789      *
0790      *
0791      * SYNOPSIS:
0792      *
0793      * float x, y, k1ef();
0794      *
0795      * y = k1ef( x );
0796      *
0797      *
0798      *
0799      * DESCRIPTION:
0800      *
0801      * Returns exponentially scaled modified Bessel function
0802      * of the third kind of order one of the argument:
0803      *
0804      *      k1e(x) = exp(x) * k1(x).
0805      *
0806      *
0807      *
0808      * ACCURACY:
0809      *
0810      *                      Relative error:
0811      * arithmetic   domain     # trials      peak         rms
0812      *    IEEE      0, 30       30000       4.9e-7      6.7e-8
0813      * See k1().
0814      *
0815      */
0816 
0817     const float A[] = {-2.21338763073472585583E-8f, -2.43340614156596823496E-6f,
0818                         -1.73028895751305206302E-4f, -6.97572385963986435018E-3f,
0819                         -1.22611180822657148235E-1f, -3.53155960776544875667E-1f,
0820                         1.52530022733894777053E0f};
0821     const float B[] = {2.01504975519703286596E-9f, -1.03457624656780970260E-8f,
0822                        5.74108412545004946722E-8f, -3.50196060308781257119E-7f,
0823                        2.40648494783721712015E-6f, -1.93619797416608296024E-5f,
0824                        1.95215518471351631108E-4f, -2.85781685962277938680E-3f,
0825                        1.03923736576817238437E-1f, 2.72062619048444266945E0f};
0826     const T MAXNUM = pset1<T>(NumTraits<float>::infinity());
0827     const T two = pset1<T>(2.0);
0828     T x_le_two = pdiv(internal::pchebevl<T, 7>::run(
0829         pmadd(x, x, pset1<T>(-2.0)), A), x);
0830     x_le_two = pmadd(
0831         generic_i1<T, float>::run(x), plog(pmul(pset1<T>(0.5), x)), x_le_two);
0832     x_le_two = pmul(x_le_two, pexp(x));
0833     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0834     T x_gt_two = pmul(
0835         internal::pchebevl<T, 10>::run(
0836             psub(pdiv(pset1<T>(8.0), x), two), B),
0837         prsqrt(x));
0838     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
0839   }
0840 };
0841 
0842 template <typename T>
0843 struct generic_k1e<T, double> {
0844   EIGEN_DEVICE_FUNC
0845   static EIGEN_STRONG_INLINE T run(const T& x) {
0846     /*  k1e.c
0847      *
0848      *  Modified Bessel function, third kind, order one,
0849      *  exponentially scaled
0850      *
0851      *
0852      *
0853      * SYNOPSIS:
0854      *
0855      * double x, y, k1e();
0856      *
0857      * y = k1e( x );
0858      *
0859      *
0860      *
0861      * DESCRIPTION:
0862      *
0863      * Returns exponentially scaled modified Bessel function
0864      * of the third kind of order one of the argument:
0865      *
0866      *      k1e(x) = exp(x) * k1(x).
0867      *
0868      *
0869      *
0870      * ACCURACY:
0871      *
0872      *                      Relative error:
0873      * arithmetic   domain     # trials      peak         rms
0874      *    IEEE      0, 30       30000       7.8e-16     1.2e-16
0875      * See k1().
0876      *
0877      */
0878     const double A[] = {-7.02386347938628759343E-18, -2.42744985051936593393E-15,
0879                         -6.66690169419932900609E-13, -1.41148839263352776110E-10,
0880                         -2.21338763073472585583E-8, -2.43340614156596823496E-6,
0881                         -1.73028895751305206302E-4, -6.97572385963986435018E-3,
0882                         -1.22611180822657148235E-1, -3.53155960776544875667E-1,
0883                         1.52530022733894777053E0};
0884     const double B[] = {-5.75674448366501715755E-18, 1.79405087314755922667E-17,
0885                         -5.68946255844285935196E-17, 1.83809354436663880070E-16,
0886                         -6.05704724837331885336E-16, 2.03870316562433424052E-15,
0887                         -7.01983709041831346144E-15, 2.47715442448130437068E-14,
0888                         -8.97670518232499435011E-14, 3.34841966607842919884E-13,
0889                         -1.28917396095102890680E-12, 5.13963967348173025100E-12,
0890                         -2.12996783842756842877E-11, 9.21831518760500529508E-11,
0891                         -4.19035475934189648750E-10, 2.01504975519703286596E-9,
0892                         -1.03457624656780970260E-8, 5.74108412545004946722E-8,
0893                         -3.50196060308781257119E-7, 2.40648494783721712015E-6,
0894                         -1.93619797416608296024E-5, 1.95215518471351631108E-4,
0895                         -2.85781685962277938680E-3, 1.03923736576817238437E-1,
0896                         2.72062619048444266945E0};
0897     const T MAXNUM = pset1<T>(NumTraits<double>::infinity());
0898     const T two = pset1<T>(2.0);
0899     T x_le_two = pdiv(internal::pchebevl<T, 11>::run(
0900         pmadd(x, x, pset1<T>(-2.0)), A), x);
0901     x_le_two = pmadd(
0902         generic_i1<T, double>::run(x), plog(pmul(pset1<T>(0.5), x)), x_le_two);
0903     x_le_two = pmul(x_le_two, pexp(x));
0904     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0905     T x_gt_two = pmul(
0906         internal::pchebevl<T, 25>::run(
0907             psub(pdiv(pset1<T>(8.0), x), two), B),
0908         prsqrt(x));
0909     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
0910   }
0911 };
0912 
0913 template <typename T>
0914 struct bessel_k1e_impl {
0915   EIGEN_DEVICE_FUNC
0916   static EIGEN_STRONG_INLINE T run(const T x) {
0917     return generic_k1e<T>::run(x);
0918   }
0919 };
0920 
0921 template <typename T>
0922 struct bessel_k1_retval {
0923   typedef T type;
0924 };
0925 
0926 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
0927 struct generic_k1 {
0928   EIGEN_DEVICE_FUNC
0929   static EIGEN_STRONG_INLINE T run(const T&) {
0930     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
0931                         THIS_TYPE_IS_NOT_SUPPORTED);
0932     return ScalarType(0);
0933   }
0934 };
0935 
0936 template <typename T>
0937 struct generic_k1<T, float> {
0938   EIGEN_DEVICE_FUNC
0939   static EIGEN_STRONG_INLINE T run(const T& x) {
0940     /* k1f.c
0941      *  Modified Bessel function, third kind, order one
0942      *
0943      *
0944      *
0945      * SYNOPSIS:
0946      *
0947      * float x, y, k1f();
0948      *
0949      * y = k1f( x );
0950      *
0951      *
0952      *
0953      * DESCRIPTION:
0954      *
0955      * Computes the modified Bessel function of the third kind
0956      * of order one of the argument.
0957      *
0958      * The range is partitioned into the two intervals [0,2] and
0959      * (2, infinity).  Chebyshev polynomial expansions are employed
0960      * in each interval.
0961      *
0962      *
0963      *
0964      * ACCURACY:
0965      *
0966      *                      Relative error:
0967      * arithmetic   domain     # trials      peak         rms
0968      *    IEEE      0, 30       30000       4.6e-7      7.6e-8
0969      *
0970      * ERROR MESSAGES:
0971      *
0972      *   message         condition      value returned
0973      * k1 domain          x <= 0          MAXNUM
0974      *
0975      */
0976 
0977     const float A[] = {-2.21338763073472585583E-8f, -2.43340614156596823496E-6f,
0978                         -1.73028895751305206302E-4f, -6.97572385963986435018E-3f,
0979                         -1.22611180822657148235E-1f, -3.53155960776544875667E-1f,
0980                         1.52530022733894777053E0f};
0981     const float B[] = {2.01504975519703286596E-9f, -1.03457624656780970260E-8f,
0982                        5.74108412545004946722E-8f, -3.50196060308781257119E-7f,
0983                        2.40648494783721712015E-6f, -1.93619797416608296024E-5f,
0984                        1.95215518471351631108E-4f, -2.85781685962277938680E-3f,
0985                        1.03923736576817238437E-1f, 2.72062619048444266945E0f};
0986     const T MAXNUM = pset1<T>(NumTraits<float>::infinity());
0987     const T two = pset1<T>(2.0);
0988     T x_le_two = pdiv(internal::pchebevl<T, 7>::run(
0989         pmadd(x, x, pset1<T>(-2.0)), A), x);
0990     x_le_two = pmadd(
0991         generic_i1<T, float>::run(x), plog(pmul(pset1<T>(0.5), x)), x_le_two);
0992     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
0993     T x_gt_two = pmul(
0994         pexp(pnegate(x)),
0995         pmul(
0996             internal::pchebevl<T, 10>::run(
0997                 psub(pdiv(pset1<T>(8.0), x), two), B),
0998             prsqrt(x)));
0999     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
1000   }
1001 };
1002 
1003 template <typename T>
1004 struct generic_k1<T, double> {
1005   EIGEN_DEVICE_FUNC
1006   static EIGEN_STRONG_INLINE T run(const T& x) {
1007     /*  k1.c
1008      *  Modified Bessel function, third kind, order one
1009      *
1010      *
1011      *
1012      * SYNOPSIS:
1013      *
1014      * float x, y, k1f();
1015      *
1016      * y = k1f( x );
1017      *
1018      *
1019      *
1020      * DESCRIPTION:
1021      *
1022      * Computes the modified Bessel function of the third kind
1023      * of order one of the argument.
1024      *
1025      * The range is partitioned into the two intervals [0,2] and
1026      * (2, infinity).  Chebyshev polynomial expansions are employed
1027      * in each interval.
1028      *
1029      *
1030      *
1031      * ACCURACY:
1032      *
1033      *                      Relative error:
1034      * arithmetic   domain     # trials      peak         rms
1035      *    IEEE      0, 30       30000       4.6e-7      7.6e-8
1036      *
1037      * ERROR MESSAGES:
1038      *
1039      *   message         condition      value returned
1040      * k1 domain          x <= 0          MAXNUM
1041      *
1042      */
1043     const double A[] = {-7.02386347938628759343E-18, -2.42744985051936593393E-15,
1044                         -6.66690169419932900609E-13, -1.41148839263352776110E-10,
1045                         -2.21338763073472585583E-8, -2.43340614156596823496E-6,
1046                         -1.73028895751305206302E-4, -6.97572385963986435018E-3,
1047                         -1.22611180822657148235E-1, -3.53155960776544875667E-1,
1048                         1.52530022733894777053E0};
1049     const double B[] = {-5.75674448366501715755E-18, 1.79405087314755922667E-17,
1050                         -5.68946255844285935196E-17, 1.83809354436663880070E-16,
1051                         -6.05704724837331885336E-16, 2.03870316562433424052E-15,
1052                         -7.01983709041831346144E-15, 2.47715442448130437068E-14,
1053                         -8.97670518232499435011E-14, 3.34841966607842919884E-13,
1054                         -1.28917396095102890680E-12, 5.13963967348173025100E-12,
1055                         -2.12996783842756842877E-11, 9.21831518760500529508E-11,
1056                         -4.19035475934189648750E-10, 2.01504975519703286596E-9,
1057                         -1.03457624656780970260E-8, 5.74108412545004946722E-8,
1058                         -3.50196060308781257119E-7, 2.40648494783721712015E-6,
1059                         -1.93619797416608296024E-5, 1.95215518471351631108E-4,
1060                         -2.85781685962277938680E-3, 1.03923736576817238437E-1,
1061                         2.72062619048444266945E0};
1062     const T MAXNUM = pset1<T>(NumTraits<double>::infinity());
1063     const T two = pset1<T>(2.0);
1064     T x_le_two = pdiv(internal::pchebevl<T, 11>::run(
1065         pmadd(x, x, pset1<T>(-2.0)), A), x);
1066     x_le_two = pmadd(
1067         generic_i1<T, double>::run(x), plog(pmul(pset1<T>(0.5), x)), x_le_two);
1068     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), MAXNUM, x_le_two);
1069     T x_gt_two = pmul(
1070         pexp(-x),
1071         pmul(
1072             internal::pchebevl<T, 25>::run(
1073                 psub(pdiv(pset1<T>(8.0), x), two), B),
1074             prsqrt(x)));
1075     return pselect(pcmp_le(x, two), x_le_two, x_gt_two);
1076   }
1077 };
1078 
1079 template <typename T>
1080 struct bessel_k1_impl {
1081   EIGEN_DEVICE_FUNC
1082   static EIGEN_STRONG_INLINE T run(const T x) {
1083     return generic_k1<T>::run(x);
1084   }
1085 };
1086 
1087 template <typename T>
1088 struct bessel_j0_retval {
1089   typedef T type;
1090 };
1091 
1092 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
1093 struct generic_j0 {
1094   EIGEN_DEVICE_FUNC
1095   static EIGEN_STRONG_INLINE T run(const T&) {
1096     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
1097                         THIS_TYPE_IS_NOT_SUPPORTED);
1098     return ScalarType(0);
1099   }
1100 };
1101 
1102 template <typename T>
1103 struct generic_j0<T, float> {
1104   EIGEN_DEVICE_FUNC
1105   static EIGEN_STRONG_INLINE T run(const T& x) {
1106     /* j0f.c
1107      *  Bessel function of order zero
1108      *
1109      *
1110      *
1111      * SYNOPSIS:
1112      *
1113      * float x, y, j0f();
1114      *
1115      * y = j0f( x );
1116      *
1117      *
1118      *
1119      * DESCRIPTION:
1120      *
1121      * Returns Bessel function of order zero of the argument.
1122      *
1123      * The domain is divided into the intervals [0, 2] and
1124      * (2, infinity). In the first interval the following polynomial
1125      * approximation is used:
1126      *
1127      *
1128      *        2         2         2
1129      * (w - r  ) (w - r  ) (w - r  ) P(w)
1130      *       1         2         3
1131      *
1132      *            2
1133      * where w = x  and the three r's are zeros of the function.
1134      *
1135      * In the second interval, the modulus and phase are approximated
1136      * by polynomials of the form Modulus(x) = sqrt(1/x) Q(1/x)
1137      * and Phase(x) = x + 1/x R(1/x^2) - pi/4.  The function is
1138      *
1139      *   j0(x) = Modulus(x) cos( Phase(x) ).
1140      *
1141      *
1142      *
1143      * ACCURACY:
1144      *
1145      *                      Absolute error:
1146      * arithmetic   domain     # trials      peak         rms
1147      *    IEEE      0, 2        100000      1.3e-7      3.6e-8
1148      *    IEEE      2, 32       100000      1.9e-7      5.4e-8
1149      *
1150      */
1151 
1152     const float JP[] = {-6.068350350393235E-008f, 6.388945720783375E-006f,
1153                         -3.969646342510940E-004f, 1.332913422519003E-002f,
1154                         -1.729150680240724E-001f};
1155     const float MO[] = {-6.838999669318810E-002f, 1.864949361379502E-001f,
1156                         -2.145007480346739E-001f, 1.197549369473540E-001f,
1157                         -3.560281861530129E-003f, -4.969382655296620E-002f,
1158                         -3.355424622293709E-006f, 7.978845717621440E-001f};
1159     const float PH[] = {3.242077816988247E+001f, -3.630592630518434E+001f,
1160                         1.756221482109099E+001f, -4.974978466280903E+000f,
1161                         1.001973420681837E+000f, -1.939906941791308E-001f,
1162                         6.490598792654666E-002f, -1.249992184872738E-001f};
1163     const T DR1 =  pset1<T>(5.78318596294678452118f);
1164     const T NEG_PIO4F = pset1<T>(-0.7853981633974483096f); /* -pi / 4 */
1165     T y = pabs(x);
1166     T z = pmul(y, y);
1167     T y_le_two = pselect(
1168         pcmp_lt(y, pset1<T>(1.0e-3f)),
1169         pmadd(z, pset1<T>(-0.25f), pset1<T>(1.0f)),
1170         pmul(psub(z, DR1), internal::ppolevl<T, 4>::run(z, JP)));
1171     T q = pdiv(pset1<T>(1.0f), y);
1172     T w = prsqrt(y);
1173     T p = pmul(w, internal::ppolevl<T, 7>::run(q, MO));
1174     w = pmul(q, q);
1175     T yn = pmadd(q, internal::ppolevl<T, 7>::run(w, PH), NEG_PIO4F);
1176     T y_gt_two = pmul(p, pcos(padd(yn, y)));
1177     return pselect(pcmp_le(y, pset1<T>(2.0)), y_le_two, y_gt_two);
1178   }
1179 };
1180 
1181 template <typename T>
1182 struct generic_j0<T, double> {
1183   EIGEN_DEVICE_FUNC
1184   static EIGEN_STRONG_INLINE T run(const T& x) {
1185     /*  j0.c
1186      *  Bessel function of order zero
1187      *
1188      *
1189      *
1190      * SYNOPSIS:
1191      *
1192      * double x, y, j0();
1193      *
1194      * y = j0( x );
1195      *
1196      *
1197      *
1198      * DESCRIPTION:
1199      *
1200      * Returns Bessel function of order zero of the argument.
1201      *
1202      * The domain is divided into the intervals [0, 5] and
1203      * (5, infinity). In the first interval the following rational
1204      * approximation is used:
1205      *
1206      *
1207      *        2         2
1208      * (w - r  ) (w - r  ) P (w) / Q (w)
1209      *       1         2    3       8
1210      *
1211      *            2
1212      * where w = x  and the two r's are zeros of the function.
1213      *
1214      * In the second interval, the Hankel asymptotic expansion
1215      * is employed with two rational functions of degree 6/6
1216      * and 7/7.
1217      *
1218      *
1219      *
1220      * ACCURACY:
1221      *
1222      *                      Absolute error:
1223      * arithmetic   domain     # trials      peak         rms
1224      *    DEC       0, 30       10000       4.4e-17     6.3e-18
1225      *    IEEE      0, 30       60000       4.2e-16     1.1e-16
1226      *
1227      */
1228     const double PP[] = {7.96936729297347051624E-4, 8.28352392107440799803E-2,
1229                         1.23953371646414299388E0, 5.44725003058768775090E0,
1230                         8.74716500199817011941E0, 5.30324038235394892183E0,
1231                         9.99999999999999997821E-1};
1232     const double PQ[] = {9.24408810558863637013E-4, 8.56288474354474431428E-2,
1233                          1.25352743901058953537E0, 5.47097740330417105182E0,
1234                          8.76190883237069594232E0, 5.30605288235394617618E0,
1235                          1.00000000000000000218E0};
1236     const double QP[] = {-1.13663838898469149931E-2, -1.28252718670509318512E0,
1237                          -1.95539544257735972385E1, -9.32060152123768231369E1,
1238                          -1.77681167980488050595E2, -1.47077505154951170175E2,
1239                          -5.14105326766599330220E1, -6.05014350600728481186E0};
1240     const double QQ[] = {1.00000000000000000000E0, 6.43178256118178023184E1,
1241                          8.56430025976980587198E2, 3.88240183605401609683E3,
1242                          7.24046774195652478189E3, 5.93072701187316984827E3,
1243                          2.06209331660327847417E3, 2.42005740240291393179E2};
1244     const double RP[] = {-4.79443220978201773821E9, 1.95617491946556577543E12,
1245                          -2.49248344360967716204E14, 9.70862251047306323952E15};
1246     const double RQ[] = {1.00000000000000000000E0, 4.99563147152651017219E2,
1247                          1.73785401676374683123E5, 4.84409658339962045305E7,
1248                          1.11855537045356834862E10, 2.11277520115489217587E12,
1249                          3.10518229857422583814E14, 3.18121955943204943306E16,
1250                          1.71086294081043136091E18};
1251     const T DR1 = pset1<T>(5.78318596294678452118E0);
1252     const T DR2 = pset1<T>(3.04712623436620863991E1);
1253     const T SQ2OPI = pset1<T>(7.9788456080286535587989E-1); /* sqrt(2 / pi) */
1254     const T NEG_PIO4 = pset1<T>(-0.7853981633974483096); /* pi / 4 */
1255 
1256     T y = pabs(x);
1257     T z = pmul(y, y);
1258     T y_le_five = pselect(
1259         pcmp_lt(y, pset1<T>(1.0e-5)),
1260         pmadd(z, pset1<T>(-0.25), pset1<T>(1.0)),
1261         pmul(pmul(psub(z, DR1), psub(z, DR2)),
1262              pdiv(internal::ppolevl<T, 3>::run(z, RP),
1263                   internal::ppolevl<T, 8>::run(z, RQ))));
1264     T s = pdiv(pset1<T>(25.0), z);
1265     T p = pdiv(
1266         internal::ppolevl<T, 6>::run(s, PP),
1267         internal::ppolevl<T, 6>::run(s, PQ));
1268     T q = pdiv(
1269         internal::ppolevl<T, 7>::run(s, QP),
1270         internal::ppolevl<T, 7>::run(s, QQ));
1271     T yn = padd(y, NEG_PIO4);
1272     T w = pdiv(pset1<T>(-5.0), y);
1273     p = pmadd(p, pcos(yn), pmul(w, pmul(q, psin(yn))));
1274     T y_gt_five = pmul(p, pmul(SQ2OPI, prsqrt(y)));
1275     return pselect(pcmp_le(y, pset1<T>(5.0)), y_le_five, y_gt_five);
1276   }
1277 };
1278 
1279 template <typename T>
1280 struct bessel_j0_impl {
1281   EIGEN_DEVICE_FUNC
1282   static EIGEN_STRONG_INLINE T run(const T x) {
1283     return generic_j0<T>::run(x);
1284   }
1285 };
1286 
1287 template <typename T>
1288 struct bessel_y0_retval {
1289   typedef T type;
1290 };
1291 
1292 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
1293 struct generic_y0 {
1294   EIGEN_DEVICE_FUNC
1295   static EIGEN_STRONG_INLINE T run(const T&) {
1296     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
1297                         THIS_TYPE_IS_NOT_SUPPORTED);
1298     return ScalarType(0);
1299   }
1300 };
1301 
1302 template <typename T>
1303 struct generic_y0<T, float> {
1304   EIGEN_DEVICE_FUNC
1305   static EIGEN_STRONG_INLINE T run(const T& x) {
1306     /* j0f.c
1307      *  Bessel function of the second kind, order zero
1308      *
1309      *
1310      *
1311      * SYNOPSIS:
1312      *
1313      * float x, y, y0f();
1314      *
1315      * y = y0f( x );
1316      *
1317      *
1318      *
1319      * DESCRIPTION:
1320      *
1321      * Returns Bessel function of the second kind, of order
1322      * zero, of the argument.
1323      *
1324      * The domain is divided into the intervals [0, 2] and
1325      * (2, infinity). In the first interval a rational approximation
1326      * R(x) is employed to compute
1327      *
1328      *                  2         2         2
1329      * y0(x)  =  (w - r  ) (w - r  ) (w - r  ) R(x)  +  2/pi ln(x) j0(x).
1330      *                 1         2         3
1331      *
1332      * Thus a call to j0() is required.  The three zeros are removed
1333      * from R(x) to improve its numerical stability.
1334      *
1335      * In the second interval, the modulus and phase are approximated
1336      * by polynomials of the form Modulus(x) = sqrt(1/x) Q(1/x)
1337      * and Phase(x) = x + 1/x S(1/x^2) - pi/4.  Then the function is
1338      *
1339      *   y0(x) = Modulus(x) sin( Phase(x) ).
1340      *
1341      *
1342      *
1343      *
1344      * ACCURACY:
1345      *
1346      *  Absolute error, when y0(x) < 1; else relative error:
1347      *
1348      * arithmetic   domain     # trials      peak         rms
1349      *    IEEE      0,  2       100000      2.4e-7      3.4e-8
1350      *    IEEE      2, 32       100000      1.8e-7      5.3e-8
1351      *
1352      */
1353 
1354     const float YP[] = {9.454583683980369E-008f, -9.413212653797057E-006f,
1355                         5.344486707214273E-004f, -1.584289289821316E-002f,
1356                         1.707584643733568E-001f};
1357     const float MO[] = {-6.838999669318810E-002f, 1.864949361379502E-001f,
1358                         -2.145007480346739E-001f, 1.197549369473540E-001f,
1359                         -3.560281861530129E-003f, -4.969382655296620E-002f,
1360                         -3.355424622293709E-006f, 7.978845717621440E-001f};
1361     const float PH[] = {3.242077816988247E+001f, -3.630592630518434E+001f,
1362                         1.756221482109099E+001f, -4.974978466280903E+000f,
1363                         1.001973420681837E+000f, -1.939906941791308E-001f,
1364                         6.490598792654666E-002f, -1.249992184872738E-001f};
1365     const T YZ1 = pset1<T>(0.43221455686510834878f);
1366     const T TWOOPI =  pset1<T>(0.636619772367581343075535f); /* 2 / pi */
1367     const T NEG_PIO4F = pset1<T>(-0.7853981633974483096f); /* -pi / 4 */
1368     const T NEG_MAXNUM = pset1<T>(-NumTraits<float>::infinity());
1369     T z = pmul(x, x);
1370     T x_le_two = pmul(TWOOPI, pmul(plog(x), generic_j0<T, float>::run(x)));
1371     x_le_two = pmadd(
1372         psub(z, YZ1), internal::ppolevl<T, 4>::run(z, YP), x_le_two);
1373     x_le_two = pselect(pcmp_le(x, pset1<T>(0.0)), NEG_MAXNUM, x_le_two);
1374     T q = pdiv(pset1<T>(1.0), x);
1375     T w = prsqrt(x);
1376     T p = pmul(w, internal::ppolevl<T, 7>::run(q, MO));
1377     T u = pmul(q, q);
1378     T xn = pmadd(q, internal::ppolevl<T, 7>::run(u, PH), NEG_PIO4F);
1379     T x_gt_two = pmul(p, psin(padd(xn, x)));
1380     return pselect(pcmp_le(x, pset1<T>(2.0)), x_le_two, x_gt_two);
1381   }
1382 };
1383 
1384 template <typename T>
1385 struct generic_y0<T, double> {
1386   EIGEN_DEVICE_FUNC
1387   static EIGEN_STRONG_INLINE T run(const T& x) {
1388     /*  j0.c
1389      *  Bessel function of the second kind, order zero
1390      *
1391      *
1392      *
1393      * SYNOPSIS:
1394      *
1395      * double x, y, y0();
1396      *
1397      * y = y0( x );
1398      *
1399      *
1400      *
1401      * DESCRIPTION:
1402      *
1403      * Returns Bessel function of the second kind, of order
1404      * zero, of the argument.
1405      *
1406      * The domain is divided into the intervals [0, 5] and
1407      * (5, infinity). In the first interval a rational approximation
1408      * R(x) is employed to compute
1409      *   y0(x)  = R(x)  +   2 * log(x) * j0(x) / PI.
1410      * Thus a call to j0() is required.
1411      *
1412      * In the second interval, the Hankel asymptotic expansion
1413      * is employed with two rational functions of degree 6/6
1414      * and 7/7.
1415      *
1416      *
1417      *
1418      * ACCURACY:
1419      *
1420      *  Absolute error, when y0(x) < 1; else relative error:
1421      *
1422      * arithmetic   domain     # trials      peak         rms
1423      *    DEC       0, 30        9400       7.0e-17     7.9e-18
1424      *    IEEE      0, 30       30000       1.3e-15     1.6e-16
1425      *
1426      */
1427     const double PP[] = {7.96936729297347051624E-4, 8.28352392107440799803E-2,
1428                         1.23953371646414299388E0, 5.44725003058768775090E0,
1429                         8.74716500199817011941E0, 5.30324038235394892183E0,
1430                         9.99999999999999997821E-1};
1431     const double PQ[] = {9.24408810558863637013E-4, 8.56288474354474431428E-2,
1432                          1.25352743901058953537E0, 5.47097740330417105182E0,
1433                          8.76190883237069594232E0, 5.30605288235394617618E0,
1434                          1.00000000000000000218E0};
1435     const double QP[] = {-1.13663838898469149931E-2, -1.28252718670509318512E0,
1436                          -1.95539544257735972385E1, -9.32060152123768231369E1,
1437                          -1.77681167980488050595E2, -1.47077505154951170175E2,
1438                          -5.14105326766599330220E1, -6.05014350600728481186E0};
1439     const double QQ[] = {1.00000000000000000000E0, 6.43178256118178023184E1,
1440                          8.56430025976980587198E2, 3.88240183605401609683E3,
1441                          7.24046774195652478189E3, 5.93072701187316984827E3,
1442                          2.06209331660327847417E3, 2.42005740240291393179E2};
1443     const double YP[] = {1.55924367855235737965E4, -1.46639295903971606143E7,
1444                          5.43526477051876500413E9, -9.82136065717911466409E11,
1445                          8.75906394395366999549E13, -3.46628303384729719441E15,
1446                          4.42733268572569800351E16, -1.84950800436986690637E16};
1447     const double YQ[] = {1.00000000000000000000E0,  1.04128353664259848412E3,
1448                          6.26107330137134956842E5, 2.68919633393814121987E8,
1449                          8.64002487103935000337E10, 2.02979612750105546709E13,
1450                          3.17157752842975028269E15, 2.50596256172653059228E17};
1451     const T SQ2OPI = pset1<T>(7.9788456080286535587989E-1); /* sqrt(2 / pi) */
1452     const T TWOOPI =  pset1<T>(0.636619772367581343075535); /* 2 / pi */
1453     const T NEG_PIO4 = pset1<T>(-0.7853981633974483096); /* -pi / 4 */
1454     const T NEG_MAXNUM = pset1<T>(-NumTraits<double>::infinity());
1455 
1456     T z = pmul(x, x);
1457     T x_le_five = pdiv(internal::ppolevl<T, 7>::run(z, YP),
1458                        internal::ppolevl<T, 7>::run(z, YQ));
1459     x_le_five = pmadd(
1460         pmul(TWOOPI, plog(x)), generic_j0<T, double>::run(x), x_le_five);
1461     x_le_five = pselect(pcmp_le(x, pset1<T>(0.0)), NEG_MAXNUM, x_le_five);
1462     T s = pdiv(pset1<T>(25.0), z);
1463     T p = pdiv(
1464         internal::ppolevl<T, 6>::run(s, PP),
1465         internal::ppolevl<T, 6>::run(s, PQ));
1466     T q = pdiv(
1467         internal::ppolevl<T, 7>::run(s, QP),
1468         internal::ppolevl<T, 7>::run(s, QQ));
1469     T xn = padd(x, NEG_PIO4);
1470     T w = pdiv(pset1<T>(5.0), x);
1471     p = pmadd(p, psin(xn), pmul(w, pmul(q, pcos(xn))));
1472     T x_gt_five = pmul(p, pmul(SQ2OPI, prsqrt(x)));
1473     return pselect(pcmp_le(x, pset1<T>(5.0)), x_le_five, x_gt_five);
1474   }
1475 };
1476 
1477 template <typename T>
1478 struct bessel_y0_impl {
1479   EIGEN_DEVICE_FUNC
1480   static EIGEN_STRONG_INLINE T run(const T x) {
1481     return generic_y0<T>::run(x);
1482   }
1483 };
1484 
1485 template <typename T>
1486 struct bessel_j1_retval {
1487   typedef T type;
1488 };
1489 
1490 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
1491 struct generic_j1 {
1492   EIGEN_DEVICE_FUNC
1493   static EIGEN_STRONG_INLINE T run(const T&) {
1494     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
1495                         THIS_TYPE_IS_NOT_SUPPORTED);
1496     return ScalarType(0);
1497   }
1498 };
1499 
1500 template <typename T>
1501 struct generic_j1<T, float> {
1502   EIGEN_DEVICE_FUNC
1503   static EIGEN_STRONG_INLINE T run(const T& x) {
1504     /* j1f.c
1505      *  Bessel function of order one
1506      *
1507      *
1508      *
1509      * SYNOPSIS:
1510      *
1511      * float x, y, j1f();
1512      *
1513      * y = j1f( x );
1514      *
1515      *
1516      *
1517      * DESCRIPTION:
1518      *
1519      * Returns Bessel function of order one of the argument.
1520      *
1521      * The domain is divided into the intervals [0, 2] and
1522      * (2, infinity). In the first interval a polynomial approximation
1523      *        2
1524      * (w - r  ) x P(w)
1525      *       1
1526      *                     2
1527      * is used, where w = x  and r is the first zero of the function.
1528      *
1529      * In the second interval, the modulus and phase are approximated
1530      * by polynomials of the form Modulus(x) = sqrt(1/x) Q(1/x)
1531      * and Phase(x) = x + 1/x R(1/x^2) - 3pi/4.  The function is
1532      *
1533      *   j0(x) = Modulus(x) cos( Phase(x) ).
1534      *
1535      *
1536      *
1537      * ACCURACY:
1538      *
1539      *                      Absolute error:
1540      * arithmetic   domain      # trials      peak       rms
1541      *    IEEE      0,  2       100000       1.2e-7     2.5e-8
1542      *    IEEE      2, 32       100000       2.0e-7     5.3e-8
1543      *
1544      *
1545      */
1546 
1547     const float JP[] = {-4.878788132172128E-009f, 6.009061827883699E-007f,
1548                         -4.541343896997497E-005f, 1.937383947804541E-003f,
1549                         -3.405537384615824E-002f};
1550     const float MO1[] = {6.913942741265801E-002f, -2.284801500053359E-001f,
1551                         3.138238455499697E-001f, -2.102302420403875E-001f,
1552                         5.435364690523026E-003f, 1.493389585089498E-001f,
1553                         4.976029650847191E-006f, 7.978845453073848E-001f};
1554     const float PH1[] = {-4.497014141919556E+001f, 5.073465654089319E+001f,
1555                         -2.485774108720340E+001f, 7.222973196770240E+000f,
1556                         -1.544842782180211E+000f, 3.503787691653334E-001f,
1557                         -1.637986776941202E-001f, 3.749989509080821E-001f};
1558     const T Z1 = pset1<T>(1.46819706421238932572E1f);
1559     const T NEG_THPIO4F = pset1<T>(-2.35619449019234492885f);    /* -3*pi/4 */
1560 
1561     T y = pabs(x);
1562     T z = pmul(y, y);
1563     T y_le_two = pmul(
1564         psub(z, Z1),
1565         pmul(x, internal::ppolevl<T, 4>::run(z, JP)));
1566     T q = pdiv(pset1<T>(1.0f), y);
1567     T w = prsqrt(y);
1568     T p = pmul(w, internal::ppolevl<T, 7>::run(q, MO1));
1569     w = pmul(q, q);
1570     T yn = pmadd(q, internal::ppolevl<T, 7>::run(w, PH1), NEG_THPIO4F);
1571     T y_gt_two = pmul(p, pcos(padd(yn, y)));
1572     // j1 is an odd function. This implementation differs from cephes to
1573     // take this fact in to account. Cephes returns -j1(x) for y > 2 range.
1574     y_gt_two = pselect(
1575         pcmp_lt(x, pset1<T>(0.0f)), pnegate(y_gt_two), y_gt_two);
1576     return pselect(pcmp_le(y, pset1<T>(2.0f)), y_le_two, y_gt_two);
1577   }
1578 };
1579 
1580 template <typename T>
1581 struct generic_j1<T, double> {
1582   EIGEN_DEVICE_FUNC
1583   static EIGEN_STRONG_INLINE T run(const T& x) {
1584     /*  j1.c
1585      *  Bessel function of order one
1586      *
1587      *
1588      *
1589      * SYNOPSIS:
1590      *
1591      * double x, y, j1();
1592      *
1593      * y = j1( x );
1594      *
1595      *
1596      *
1597      * DESCRIPTION:
1598      *
1599      * Returns Bessel function of order one of the argument.
1600      *
1601      * The domain is divided into the intervals [0, 8] and
1602      * (8, infinity). In the first interval a 24 term Chebyshev
1603      * expansion is used. In the second, the asymptotic
1604      * trigonometric representation is employed using two
1605      * rational functions of degree 5/5.
1606      *
1607      *
1608      *
1609      * ACCURACY:
1610      *
1611      *                      Absolute error:
1612      * arithmetic   domain      # trials      peak         rms
1613      *    DEC       0, 30       10000       4.0e-17     1.1e-17
1614      *    IEEE      0, 30       30000       2.6e-16     1.1e-16
1615      *
1616      */
1617     const double PP[] = {7.62125616208173112003E-4, 7.31397056940917570436E-2,
1618                          1.12719608129684925192E0, 5.11207951146807644818E0,
1619                          8.42404590141772420927E0, 5.21451598682361504063E0,
1620                          1.00000000000000000254E0};
1621     const double PQ[] = {5.71323128072548699714E-4, 6.88455908754495404082E-2,
1622                          1.10514232634061696926E0, 5.07386386128601488557E0,
1623                          8.39985554327604159757E0, 5.20982848682361821619E0,
1624                          9.99999999999999997461E-1};
1625     const double QP[] = {5.10862594750176621635E-2, 4.98213872951233449420E0,
1626                          7.58238284132545283818E1, 3.66779609360150777800E2,
1627                          7.10856304998926107277E2, 5.97489612400613639965E2,
1628                          2.11688757100572135698E2, 2.52070205858023719784E1};
1629     const double QQ[] = {1.00000000000000000000E0, 7.42373277035675149943E1,
1630                          1.05644886038262816351E3, 4.98641058337653607651E3,
1631                          9.56231892404756170795E3, 7.99704160447350683650E3,
1632                          2.82619278517639096600E3, 3.36093607810698293419E2};
1633     const double RP[] = {-8.99971225705559398224E8, 4.52228297998194034323E11,
1634                          -7.27494245221818276015E13, 3.68295732863852883286E15};
1635     const double RQ[] = {1.00000000000000000000E0, 6.20836478118054335476E2,
1636                          2.56987256757748830383E5, 8.35146791431949253037E7,
1637                          2.21511595479792499675E10, 4.74914122079991414898E12,
1638                          7.84369607876235854894E14, 8.95222336184627338078E16,
1639                          5.32278620332680085395E18};
1640     const T Z1 = pset1<T>(1.46819706421238932572E1);
1641     const T Z2 = pset1<T>(4.92184563216946036703E1);
1642     const T NEG_THPIO4 = pset1<T>(-2.35619449019234492885);    /* -3*pi/4 */
1643     const T SQ2OPI = pset1<T>(7.9788456080286535587989E-1); /* sqrt(2 / pi) */
1644     T y = pabs(x);
1645     T z = pmul(y, y);
1646     T y_le_five = pdiv(internal::ppolevl<T, 3>::run(z, RP),
1647                        internal::ppolevl<T, 8>::run(z, RQ));
1648     y_le_five = pmul(pmul(pmul(y_le_five, x), psub(z, Z1)), psub(z, Z2));
1649     T s = pdiv(pset1<T>(25.0), z);
1650     T p = pdiv(
1651         internal::ppolevl<T, 6>::run(s, PP),
1652         internal::ppolevl<T, 6>::run(s, PQ));
1653     T q = pdiv(
1654         internal::ppolevl<T, 7>::run(s, QP),
1655         internal::ppolevl<T, 7>::run(s, QQ));
1656     T yn = padd(y, NEG_THPIO4);
1657     T w = pdiv(pset1<T>(-5.0), y);
1658     p = pmadd(p, pcos(yn), pmul(w, pmul(q, psin(yn))));
1659     T y_gt_five = pmul(p, pmul(SQ2OPI, prsqrt(y)));
1660     // j1 is an odd function. This implementation differs from cephes to
1661     // take this fact in to account. Cephes returns -j1(x) for y > 5 range.
1662     y_gt_five = pselect(
1663         pcmp_lt(x, pset1<T>(0.0)), pnegate(y_gt_five), y_gt_five);
1664     return pselect(pcmp_le(y, pset1<T>(5.0)), y_le_five, y_gt_five);
1665   }
1666 };
1667 
1668 template <typename T>
1669 struct bessel_j1_impl {
1670   EIGEN_DEVICE_FUNC
1671   static EIGEN_STRONG_INLINE T run(const T x) {
1672     return generic_j1<T>::run(x);
1673   }
1674 };
1675 
1676 template <typename T>
1677 struct bessel_y1_retval {
1678   typedef T type;
1679 };
1680 
1681 template <typename T, typename ScalarType = typename unpacket_traits<T>::type>
1682 struct generic_y1 {
1683   EIGEN_DEVICE_FUNC
1684   static EIGEN_STRONG_INLINE T run(const T&) {
1685     EIGEN_STATIC_ASSERT((internal::is_same<T, T>::value == false),
1686                         THIS_TYPE_IS_NOT_SUPPORTED);
1687     return ScalarType(0);
1688   }
1689 };
1690 
1691 template <typename T>
1692 struct generic_y1<T, float> {
1693   EIGEN_DEVICE_FUNC
1694   static EIGEN_STRONG_INLINE T run(const T& x) {
1695     /* j1f.c
1696      *  Bessel function of second kind of order one
1697      *
1698      *
1699      *
1700      * SYNOPSIS:
1701      *
1702      * double x, y, y1();
1703      *
1704      * y = y1( x );
1705      *
1706      *
1707      *
1708      * DESCRIPTION:
1709      *
1710      * Returns Bessel function of the second kind of order one
1711      * of the argument.
1712      *
1713      * The domain is divided into the intervals [0, 2] and
1714      * (2, infinity). In the first interval a rational approximation
1715      * R(x) is employed to compute
1716      *
1717      *                  2
1718      * y0(x)  =  (w - r  ) x R(x^2)  +  2/pi (ln(x) j1(x) - 1/x) .
1719      *                 1
1720      *
1721      * Thus a call to j1() is required.
1722      *
1723      * In the second interval, the modulus and phase are approximated
1724      * by polynomials of the form Modulus(x) = sqrt(1/x) Q(1/x)
1725      * and Phase(x) = x + 1/x S(1/x^2) - 3pi/4.  Then the function is
1726      *
1727      *   y0(x) = Modulus(x) sin( Phase(x) ).
1728      *
1729      *
1730      *
1731      *
1732      * ACCURACY:
1733      *
1734      *                      Absolute error:
1735      * arithmetic   domain      # trials      peak         rms
1736      *    IEEE      0,  2       100000       2.2e-7     4.6e-8
1737      *    IEEE      2, 32       100000       1.9e-7     5.3e-8
1738      *
1739      * (error criterion relative when |y1| > 1).
1740      *
1741      */
1742 
1743     const float YP[] = {8.061978323326852E-009f, -9.496460629917016E-007f,
1744                         6.719543806674249E-005f, -2.641785726447862E-003f,
1745                         4.202369946500099E-002f};
1746     const float MO1[] = {6.913942741265801E-002f, -2.284801500053359E-001f,
1747                         3.138238455499697E-001f, -2.102302420403875E-001f,
1748                         5.435364690523026E-003f, 1.493389585089498E-001f,
1749                         4.976029650847191E-006f, 7.978845453073848E-001f};
1750     const float PH1[] = {-4.497014141919556E+001f, 5.073465654089319E+001f,
1751                         -2.485774108720340E+001f, 7.222973196770240E+000f,
1752                         -1.544842782180211E+000f, 3.503787691653334E-001f,
1753                         -1.637986776941202E-001f, 3.749989509080821E-001f};
1754     const T YO1 = pset1<T>(4.66539330185668857532f);
1755     const T NEG_THPIO4F = pset1<T>(-2.35619449019234492885f);    /* -3*pi/4 */
1756     const T TWOOPI = pset1<T>(0.636619772367581343075535f); /* 2/pi */
1757     const T NEG_MAXNUM = pset1<T>(-NumTraits<float>::infinity());
1758 
1759     T z = pmul(x, x);
1760     T x_le_two = pmul(psub(z, YO1), internal::ppolevl<T, 4>::run(z, YP));
1761     x_le_two = pmadd(
1762        x_le_two, x,
1763        pmul(TWOOPI, pmadd(
1764            generic_j1<T, float>::run(x), plog(x),
1765            pdiv(pset1<T>(-1.0f), x))));
1766     x_le_two = pselect(pcmp_lt(x, pset1<T>(0.0f)), NEG_MAXNUM, x_le_two);
1767 
1768     T q = pdiv(pset1<T>(1.0), x);
1769     T w = prsqrt(x);
1770     T p = pmul(w, internal::ppolevl<T, 7>::run(q, MO1));
1771     w = pmul(q, q);
1772     T xn = pmadd(q, internal::ppolevl<T, 7>::run(w, PH1), NEG_THPIO4F);
1773     T x_gt_two = pmul(p, psin(padd(xn, x)));
1774     return pselect(pcmp_le(x, pset1<T>(2.0)), x_le_two, x_gt_two);
1775   }
1776 };
1777 
1778 template <typename T>
1779 struct generic_y1<T, double> {
1780   EIGEN_DEVICE_FUNC
1781   static EIGEN_STRONG_INLINE T run(const T& x) {
1782     /*  j1.c
1783      *  Bessel function of second kind of order one
1784      *
1785      *
1786      *
1787      * SYNOPSIS:
1788      *
1789      * double x, y, y1();
1790      *
1791      * y = y1( x );
1792      *
1793      *
1794      *
1795      * DESCRIPTION:
1796      *
1797      * Returns Bessel function of the second kind of order one
1798      * of the argument.
1799      *
1800      * The domain is divided into the intervals [0, 8] and
1801      * (8, infinity). In the first interval a 25 term Chebyshev
1802      * expansion is used, and a call to j1() is required.
1803      * In the second, the asymptotic trigonometric representation
1804      * is employed using two rational functions of degree 5/5.
1805      *
1806      *
1807      *
1808      * ACCURACY:
1809      *
1810      *                      Absolute error:
1811      * arithmetic   domain      # trials      peak         rms
1812      *    DEC       0, 30       10000       8.6e-17     1.3e-17
1813      *    IEEE      0, 30       30000       1.0e-15     1.3e-16
1814      *
1815      * (error criterion relative when |y1| > 1).
1816      *
1817      */
1818     const double PP[] = {7.62125616208173112003E-4, 7.31397056940917570436E-2,
1819                          1.12719608129684925192E0, 5.11207951146807644818E0,
1820                          8.42404590141772420927E0, 5.21451598682361504063E0,
1821                          1.00000000000000000254E0};
1822     const double PQ[] = {5.71323128072548699714E-4, 6.88455908754495404082E-2,
1823                          1.10514232634061696926E0, 5.07386386128601488557E0,
1824                          8.39985554327604159757E0, 5.20982848682361821619E0,
1825                          9.99999999999999997461E-1};
1826     const double QP[] = {5.10862594750176621635E-2, 4.98213872951233449420E0,
1827                          7.58238284132545283818E1, 3.66779609360150777800E2,
1828                          7.10856304998926107277E2, 5.97489612400613639965E2,
1829                          2.11688757100572135698E2, 2.52070205858023719784E1};
1830     const double QQ[] = {1.00000000000000000000E0, 7.42373277035675149943E1,
1831                          1.05644886038262816351E3, 4.98641058337653607651E3,
1832                          9.56231892404756170795E3, 7.99704160447350683650E3,
1833                          2.82619278517639096600E3, 3.36093607810698293419E2};
1834     const double YP[] = {1.26320474790178026440E9, -6.47355876379160291031E11,
1835                          1.14509511541823727583E14, -8.12770255501325109621E15,
1836                          2.02439475713594898196E17, -7.78877196265950026825E17};
1837     const double YQ[] = {1.00000000000000000000E0, 5.94301592346128195359E2,
1838                          2.35564092943068577943E5, 7.34811944459721705660E7,
1839                          1.87601316108706159478E10, 3.88231277496238566008E12,
1840                          6.20557727146953693363E14, 6.87141087355300489866E16,
1841                          3.97270608116560655612E18};
1842     const T SQ2OPI = pset1<T>(.79788456080286535588);
1843     const T NEG_THPIO4 = pset1<T>(-2.35619449019234492885);    /* -3*pi/4 */
1844     const T TWOOPI = pset1<T>(0.636619772367581343075535); /* 2/pi */
1845     const T NEG_MAXNUM = pset1<T>(-NumTraits<double>::infinity());
1846 
1847     T z = pmul(x, x);
1848     T x_le_five = pdiv(internal::ppolevl<T, 5>::run(z, YP),
1849                    internal::ppolevl<T, 8>::run(z, YQ));
1850     x_le_five = pmadd(
1851         x_le_five, x, pmul(
1852             TWOOPI, pmadd(generic_j1<T, double>::run(x), plog(x),
1853                           pdiv(pset1<T>(-1.0), x))));
1854 
1855     x_le_five = pselect(pcmp_le(x, pset1<T>(0.0)), NEG_MAXNUM, x_le_five);
1856     T s = pdiv(pset1<T>(25.0), z);
1857     T p = pdiv(
1858         internal::ppolevl<T, 6>::run(s, PP),
1859         internal::ppolevl<T, 6>::run(s, PQ));
1860     T q = pdiv(
1861         internal::ppolevl<T, 7>::run(s, QP),
1862         internal::ppolevl<T, 7>::run(s, QQ));
1863     T xn = padd(x, NEG_THPIO4);
1864     T w = pdiv(pset1<T>(5.0), x);
1865     p = pmadd(p, psin(xn), pmul(w, pmul(q, pcos(xn))));
1866     T x_gt_five = pmul(p, pmul(SQ2OPI, prsqrt(x)));
1867     return pselect(pcmp_le(x, pset1<T>(5.0)), x_le_five, x_gt_five);
1868   }
1869 };
1870 
1871 template <typename T>
1872 struct bessel_y1_impl {
1873   EIGEN_DEVICE_FUNC
1874   static EIGEN_STRONG_INLINE T run(const T x) {
1875     return generic_y1<T>::run(x);
1876   }
1877 };
1878 
1879 }  // end namespace internal
1880 
1881 namespace numext {
1882 
1883 template <typename Scalar>
1884 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_i0, Scalar)
1885     bessel_i0(const Scalar& x) {
1886   return EIGEN_MATHFUNC_IMPL(bessel_i0, Scalar)::run(x);
1887 }
1888 
1889 template <typename Scalar>
1890 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_i0e, Scalar)
1891     bessel_i0e(const Scalar& x) {
1892   return EIGEN_MATHFUNC_IMPL(bessel_i0e, Scalar)::run(x);
1893 }
1894 
1895 template <typename Scalar>
1896 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_i1, Scalar)
1897     bessel_i1(const Scalar& x) {
1898   return EIGEN_MATHFUNC_IMPL(bessel_i1, Scalar)::run(x);
1899 }
1900 
1901 template <typename Scalar>
1902 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_i1e, Scalar)
1903     bessel_i1e(const Scalar& x) {
1904   return EIGEN_MATHFUNC_IMPL(bessel_i1e, Scalar)::run(x);
1905 }
1906 
1907 template <typename Scalar>
1908 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_k0, Scalar)
1909     bessel_k0(const Scalar& x) {
1910   return EIGEN_MATHFUNC_IMPL(bessel_k0, Scalar)::run(x);
1911 }
1912 
1913 template <typename Scalar>
1914 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_k0e, Scalar)
1915     bessel_k0e(const Scalar& x) {
1916   return EIGEN_MATHFUNC_IMPL(bessel_k0e, Scalar)::run(x);
1917 }
1918 
1919 template <typename Scalar>
1920 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_k1, Scalar)
1921     bessel_k1(const Scalar& x) {
1922   return EIGEN_MATHFUNC_IMPL(bessel_k1, Scalar)::run(x);
1923 }
1924 
1925 template <typename Scalar>
1926 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_k1e, Scalar)
1927     bessel_k1e(const Scalar& x) {
1928   return EIGEN_MATHFUNC_IMPL(bessel_k1e, Scalar)::run(x);
1929 }
1930 
1931 template <typename Scalar>
1932 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_j0, Scalar)
1933     bessel_j0(const Scalar& x) {
1934   return EIGEN_MATHFUNC_IMPL(bessel_j0, Scalar)::run(x);
1935 }
1936 
1937 template <typename Scalar>
1938 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_y0, Scalar)
1939     bessel_y0(const Scalar& x) {
1940   return EIGEN_MATHFUNC_IMPL(bessel_y0, Scalar)::run(x);
1941 }
1942 
1943 template <typename Scalar>
1944 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_j1, Scalar)
1945     bessel_j1(const Scalar& x) {
1946   return EIGEN_MATHFUNC_IMPL(bessel_j1, Scalar)::run(x);
1947 }
1948 
1949 template <typename Scalar>
1950 EIGEN_DEVICE_FUNC inline EIGEN_MATHFUNC_RETVAL(bessel_y1, Scalar)
1951     bessel_y1(const Scalar& x) {
1952   return EIGEN_MATHFUNC_IMPL(bessel_y1, Scalar)::run(x);
1953 }
1954 
1955 }  // end namespace numext
1956 
1957 }  // end namespace Eigen
1958 
1959 #endif  // EIGEN_BESSEL_FUNCTIONS_H