Mercurial > octave
view libinterp/corefcn/__expint__.cc @ 29569:29a1f8fd8ee6
move idx_vector classes inside octave namespace
* idx-vector.h, idx-vector.cc:
Move idx_vector classes inside octave namespace. Update all uses
outside of octave namespace to use octave:: tag.
* Sparse.h: Eliminate forward declaration of idx_vector.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Wed, 28 Apr 2021 13:46:02 -0400 |
parents | 7854d5752dd2 |
children | 32c3a5805893 |
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//////////////////////////////////////////////////////////////////////// // // Copyright (C) 2018-2021 The Octave Project Developers // // See the file COPYRIGHT.md in the top-level directory of this // distribution or <https://octave.org/copyright/>. // // This file is part of Octave. // // Octave 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. // // Octave 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. // // You should have received a copy of the GNU General Public License // along with Octave; see the file COPYING. If not, see // <https://www.gnu.org/licenses/>. // //////////////////////////////////////////////////////////////////////// #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include "CNDArray.h" #include "defun.h" #include "fCNDArray.h" DEFUN (__expint__, args, , doc: /* -*- texinfo -*- @deftypefn {} {@var{y} =} __expint__ (@var{x}) Continued fraction expansion for the exponential integral. @end deftypefn */) { if (args.length () != 1) print_usage (); octave_value_list retval; bool is_single = args(0).is_single_type (); int numel_x = args(0).numel (); // Initialize output dimension vector dim_vector output_dv (numel_x, 1); // Lentz's algorithm in two cases: single and double precision if (is_single) { // Initialize output and inputs FloatComplexColumnVector output (output_dv); FloatComplexNDArray x; if (numel_x == 1) x = FloatComplexNDArray (output_dv, args(0).float_complex_value ()); else x = args(0).float_complex_array_value (); // Initialize variables used in algorithm static const FloatComplex tiny = octave::math::exp2 (-50.0f); static const float eps = std::numeric_limits<float>::epsilon (); const FloatComplex cone (1.0, 0.0); const FloatComplex czero (0.0, 0.0); const int maxit = 100; // Loop over all elements for (octave_idx_type i = 0; i < numel_x; ++i) { // Catch Ctrl+C OCTAVE_QUIT; // Variable initialization for the current element FloatComplex xj = x(i); FloatComplex y = tiny; FloatComplex Cj = y; FloatComplex Dj = czero; FloatComplex alpha_j = cone; FloatComplex beta_j = xj; FloatComplex Deltaj = czero; int j = 1; // Lentz's algorithm while ((std::abs (Deltaj - cone) > eps) && (j < maxit)) { Dj = beta_j + alpha_j * Dj; if (Dj == czero) Dj = tiny; Cj = beta_j + alpha_j / Cj; if (Cj == czero) Cj = tiny; Dj = cone / Dj; Deltaj = Cj * Dj; y *= Deltaj; alpha_j = (j + 1) / 2; if ((j % 2) == 0) beta_j = xj; else beta_j = cone; j++; } output(i) = y; } retval(0) = output; } else { // Initialize output and inputs ComplexColumnVector output (output_dv); ComplexNDArray x; if (numel_x == 1) x = ComplexNDArray (output_dv, args(0).complex_value ()); else x = args(0).complex_array_value (); // Initialize variables used in algorithm static const Complex tiny = octave::math::exp2 (-100.0); static const double eps = std::numeric_limits<double>::epsilon (); const Complex cone (1.0, 0.0); const Complex czero (0.0, 0.0); const int maxit = 200; // Loop over all scenarios for (octave_idx_type i = 0; i < numel_x; ++i) { // Catch Ctrl+C OCTAVE_QUIT; // Variable initialization for the current element Complex xj = x(i); Complex y = tiny; Complex Cj = y; Complex Dj = czero; Complex alpha_j = cone; Complex beta_j = xj; Complex Deltaj = czero; int j = 1; // Lentz's algorithm while ((std::abs (Deltaj - cone) > eps) && (j < maxit)) { Dj = beta_j + alpha_j * Dj; if (Dj == czero) Dj = tiny; Cj = beta_j + alpha_j / Cj; if (Cj == czero) Cj = tiny; Dj = cone / Dj; Deltaj = Cj * Dj; y *= Deltaj; alpha_j = (j + 1) / 2; if ((j % 2) == 0) beta_j = xj; else beta_j = cone; j++; } output(i) = y; } retval(0) = output; } return retval; }