projections/impl/pj_zpoly1.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002 // This file is manually converted from PROJ4
0003
0004 // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
0005
0006 // This file was modified by Oracle on 2017, 2018.
0007 // Modifications copyright (c) 2017-2018, Oracle and/or its affiliates.
0008 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0009
0010 // Use, modification and distribution is subject to the Boost Software License,
0011 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0012 // http://www.boost.org/LICENSE_1_0.txt)
0013
0014 // This file is converted from PROJ4, http://trac.osgeo.org/proj
0015 // PROJ4 is originally written by Gerald Evenden (then of the USGS)
0016 // PROJ4 is maintained by Frank Warmerdam
0017 // PROJ4 is converted to Geometry Library by Barend Gehrels (Geodan, Amsterdam)
0018
0019 // Original copyright notice:
0020
0021 // Permission is hereby granted, free of charge, to any person obtaining a
0022 // copy of this software and associated documentation files (the "Software"),
0023 // to deal in the Software without restriction, including without limitation
0024 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
0025 // and/or sell copies of the Software, and to permit persons to whom the
0026 // Software is furnished to do so, subject to the following conditions:
0027
0028 // The above copyright notice and this permission notice shall be included
0029 // in all copies or substantial portions of the Software.
0030
0031 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
0032 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0033 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
0034 // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
0035 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
0036 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
0037 // DEALINGS IN THE SOFTWARE.
0038
0039 #ifndef BOOST_GEOMETRY_PROJECTIONS_ZPOLY1_HPP
0040 #define BOOST_GEOMETRY_PROJECTIONS_ZPOLY1_HPP
0041
0042
0043 #include <boost/geometry/srs/projections/impl/projects.hpp>
0044
0045
0046 namespace boost { namespace geometry { namespace projections { namespace detail {
0047
0048     /* evaluate complex polynomial */
0049
0050     /* note: coefficients are always from C_1 to C_n
0051     **    i.e. C_0 == (0., 0)
0052     **    n should always be >= 1 though no checks are made
0053     */
0054     template <typename T>
0055     inline pj_complex<T>
0056     pj_zpoly1(pj_complex<T> z, const pj_complex<T> *C, int n)
0057     {
0058         pj_complex<T> a;
0059         T t;
0060
0061         a = *(C += n);
0062         while (n-- > 0)
0063         {
0064             a.r = (--C)->r + z.r * (t = a.r) - z.i * a.i;
0065             a.i = C->i + z.r * a.i + z.i * t;
0066         }
0067         a.r = z.r * (t = a.r) - z.i * a.i;
0068         a.i = z.r * a.i + z.i * t;
0069         return a;
0070     }
0071
0072     /* evaluate complex polynomial and derivative */
0073     template <typename T>
0074     inline pj_complex<T>
0075     pj_zpolyd1(pj_complex<T> z, const pj_complex<T> *C, int n, pj_complex<T> *der)
0076     {
0077         T t;
0078         bool first = true;
0079
0080         pj_complex<T> a = *(C += n);
0081         pj_complex<T> b = a;
0082         while (n-- > 0)
0083         {
0084             if (first)
0085             {
0086                 first = false;
0087             }
0088             else
0089             {
0090                 b.r = a.r + z.r * (t = b.r) - z.i * b.i;
0091                 b.i = a.i + z.r * b.i + z.i * t;
0092             }
0093             a.r = (--C)->r + z.r * (t = a.r) - z.i * a.i;
0094             a.i = C->i + z.r * a.i + z.i * t;
0095         }
0096         b.r = a.r + z.r * (t = b.r) - z.i * b.i;
0097         b.i = a.i + z.r * b.i + z.i * t;
0098         a.r = z.r * (t = a.r) - z.i * a.i;
0099         a.i = z.r * a.i + z.i * t;
0100         *der = b;
0101         return a;
0102     }
0103
0104 }}}} // namespace boost::geometry::projections::detail
0105
0106 #endif