Mercurial > octave
view libinterp/corefcn/__expint__.cc @ 29961:7d6709900da7
eliminate octave:: namespace tags in DEFUN and DEFMETHOD and more
Files affected: __betainc__.cc, __contourc__.cc, __eigs__.cc,
__expint__.cc, __ftp__.cc, __gammainc__.cc, __ichol__.cc, __ilu__.cc,
__magick_read__.cc, __pchip_deriv__.cc, __qp__.cc, amd.cc, balance.cc,
besselj.cc, bsxfun.cc, call-stack.cc, ccolamd.cc, cellfun.cc, chol.cc,
colamd.cc, colloc.cc, conv2.cc, daspk.cc, dasrt.cc, dassl.cc, data.cc,
defaults.cc, dirfns.cc, display.cc, dlmread.cc, dmperm.cc, dot.cc,
eig.cc, ellipj.cc, environment.cc, error.cc, event-manager.cc, fft.cc,
fft2.cc, fftn.cc, file-io.cc, find.cc, gcd.cc, getgrent.cc,
getpwent.cc, getrusage.cc, gsvd.cc, hash.cc, help.cc, hess.cc,
hex2num.cc, input.cc, inv.cc, jsondecode.cc, jsonencode.cc,
load-path.cc, load-save.cc, lookup.cc, lsode.cc, lu.cc, max.cc,
mgorth.cc, oct-hist.cc, ordqz.cc, ordschur.cc, pager.cc, pr-output.cc,
psi.cc, qr.cc, quad.cc, quadcc.cc, qz.cc, rand.cc, regexp.cc,
schur.cc, settings.cc, sighandlers.cc, sparse.cc, spparms.cc,
sqrtm.cc, stream-euler.cc, strfind.cc, strfns.cc, sub2ind.cc, svd.cc,
symbfact.cc, symtab.cc, syscalls.cc, sysdep.cc, time.cc, toplev.cc,
tril.cc, typecast.cc, urlwrite.cc, utils.cc, variables.cc,
__delaunayn__.cc, __fltk_uigetfile__.cc, __glpk__.cc,
__init_gnuplot__.cc, __ode15__.cc, __voronoi__.cc, audiodevinfo.cc,
audioread.cc, convhulln.cc, fftw.cc, gzip.cc, ov-cell.cc, ov-class.cc,
ov-classdef.cc, ov-fcn-handle.cc, ov-struct.cc, ov-typeinfo.cc,
ov-usr-fcn.cc, octave.cc, lex.ll, oct-parse.yy, profiler.cc,
andpt-eval.cc.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Sat, 14 Aug 2021 22:48:52 -0400 |
parents | 32c3a5805893 |
children | 796f54d4ddbf |
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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" OCTAVE_NAMESPACE_BEGIN 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 = 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 = 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; } OCTAVE_NAMESPACE_END