| /* Implementation of the BESSEL_JN and BESSEL_YN transformational |
| function using a recurrence algorithm. |
| Copyright (C) 2010-2019 Free Software Foundation, Inc. |
| Contributed by Tobias Burnus <burnus@net-b.de> |
| |
| This file is part of the GNU Fortran runtime library (libgfortran). |
| |
| Libgfortran is free software; you can redistribute it and/or |
| modify it under the terms of the GNU General Public |
| License as published by the Free Software Foundation; either |
| version 3 of the License, or (at your option) any later version. |
| |
| Libgfortran is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "libgfortran.h" |
| |
| |
| |
| #define MATHFUNC(funcname) funcname ## f |
| |
| #if defined (HAVE_GFC_REAL_4) |
| |
| |
| |
| #if defined (HAVE_JNF) |
| extern void bessel_jn_r4 (gfc_array_r4 * const restrict ret, int n1, |
| int n2, GFC_REAL_4 x); |
| export_proto(bessel_jn_r4); |
| |
| void |
| bessel_jn_r4 (gfc_array_r4 * const restrict ret, int n1, int n2, GFC_REAL_4 x) |
| { |
| int i; |
| index_type stride; |
| |
| GFC_REAL_4 last1, last2, x2rev; |
| |
| stride = GFC_DESCRIPTOR_STRIDE(ret,0); |
| |
| if (ret->base_addr == NULL) |
| { |
| size_t size = n2 < n1 ? 0 : n2-n1+1; |
| GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1); |
| ret->base_addr = xmallocarray (size, sizeof (GFC_REAL_4)); |
| ret->offset = 0; |
| } |
| |
| if (unlikely (n2 < n1)) |
| return; |
| |
| if (unlikely (compile_options.bounds_check) |
| && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1)) |
| runtime_error("Incorrect extent in return value of BESSEL_JN " |
| "(%ld vs. %ld)", (long int) n2-n1, |
| (long int) GFC_DESCRIPTOR_EXTENT(ret,0)); |
| |
| stride = GFC_DESCRIPTOR_STRIDE(ret,0); |
| |
| if (unlikely (x == 0)) |
| { |
| ret->base_addr[0] = 1; |
| for (i = 1; i <= n2-n1; i++) |
| ret->base_addr[i*stride] = 0; |
| return; |
| } |
| |
| last1 = MATHFUNC(jn) (n2, x); |
| ret->base_addr[(n2-n1)*stride] = last1; |
| |
| if (n1 == n2) |
| return; |
| |
| last2 = MATHFUNC(jn) (n2 - 1, x); |
| ret->base_addr[(n2-n1-1)*stride] = last2; |
| |
| if (n1 + 1 == n2) |
| return; |
| |
| x2rev = GFC_REAL_4_LITERAL(2.)/x; |
| |
| for (i = n2-n1-2; i >= 0; i--) |
| { |
| ret->base_addr[i*stride] = x2rev * (i+1+n1) * last2 - last1; |
| last1 = last2; |
| last2 = ret->base_addr[i*stride]; |
| } |
| } |
| |
| #endif |
| |
| #if defined (HAVE_YNF) |
| extern void bessel_yn_r4 (gfc_array_r4 * const restrict ret, |
| int n1, int n2, GFC_REAL_4 x); |
| export_proto(bessel_yn_r4); |
| |
| void |
| bessel_yn_r4 (gfc_array_r4 * const restrict ret, int n1, int n2, |
| GFC_REAL_4 x) |
| { |
| int i; |
| index_type stride; |
| |
| GFC_REAL_4 last1, last2, x2rev; |
| |
| stride = GFC_DESCRIPTOR_STRIDE(ret,0); |
| |
| if (ret->base_addr == NULL) |
| { |
| size_t size = n2 < n1 ? 0 : n2-n1+1; |
| GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1); |
| ret->base_addr = xmallocarray (size, sizeof (GFC_REAL_4)); |
| ret->offset = 0; |
| } |
| |
| if (unlikely (n2 < n1)) |
| return; |
| |
| if (unlikely (compile_options.bounds_check) |
| && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1)) |
| runtime_error("Incorrect extent in return value of BESSEL_JN " |
| "(%ld vs. %ld)", (long int) n2-n1, |
| (long int) GFC_DESCRIPTOR_EXTENT(ret,0)); |
| |
| stride = GFC_DESCRIPTOR_STRIDE(ret,0); |
| |
| if (unlikely (x == 0)) |
| { |
| for (i = 0; i <= n2-n1; i++) |
| #if defined(GFC_REAL_4_INFINITY) |
| ret->base_addr[i*stride] = -GFC_REAL_4_INFINITY; |
| #else |
| ret->base_addr[i*stride] = -GFC_REAL_4_HUGE; |
| #endif |
| return; |
| } |
| |
| last1 = MATHFUNC(yn) (n1, x); |
| ret->base_addr[0] = last1; |
| |
| if (n1 == n2) |
| return; |
| |
| last2 = MATHFUNC(yn) (n1 + 1, x); |
| ret->base_addr[1*stride] = last2; |
| |
| if (n1 + 1 == n2) |
| return; |
| |
| x2rev = GFC_REAL_4_LITERAL(2.)/x; |
| |
| for (i = 2; i <= n2 - n1; i++) |
| { |
| #if defined(GFC_REAL_4_INFINITY) |
| if (unlikely (last2 == -GFC_REAL_4_INFINITY)) |
| { |
| ret->base_addr[i*stride] = -GFC_REAL_4_INFINITY; |
| } |
| else |
| #endif |
| { |
| ret->base_addr[i*stride] = x2rev * (i-1+n1) * last2 - last1; |
| last1 = last2; |
| last2 = ret->base_addr[i*stride]; |
| } |
| } |
| } |
| #endif |
| |
| #endif |
| |