00001 /*************************************************************************** 00002 ** 00003 ** This file is part of QGpCoreTools. 00004 ** 00005 ** This library is free software; you can redistribute it and/or 00006 ** modify it under the terms of the GNU Lesser General Public 00007 ** License as published by the Free Software Foundation; either 00008 ** version 2.1 of the License, or (at your option) any later version. 00009 ** 00010 ** This file is distributed in the hope that it will be useful, but WITHOUT 00011 ** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 00012 ** FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 00013 ** License for more details. 00014 ** 00015 ** You should have received a copy of the GNU Lesser General Public 00016 ** License along with this library; if not, write to the Free Software 00017 ** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00018 ** 00019 ** See http://www.geopsy.org for more information. 00020 ** 00021 ** Created : 2009-04-11 00022 ** Authors : 00023 ** Marc Wathelet 00024 ** Marc Wathelet (LGIT, Grenoble, France) 00025 ** 00026 ***************************************************************************/ 00027 00028 #ifndef COMPLEXEXPONENTIAL_H 00029 #define COMPLEXEXPONENTIAL_H 00030 00031 #include "QGpCoreToolsDLLExport.h" 00032 #include "Complex.h" 00033 00034 namespace QGpCoreTools { 00035 00036 class QGPCORETOOLS_EXPORT ComplexExponential 00037 { 00038 public: 00039 enum Sign {Positive, Negative}; 00040 ComplexExponential(int n, Sign s); 00041 ~ComplexExponential(); 00042 00043 inline const Complex& value(long int x); 00044 private: 00045 Complex * _cache; 00046 Sign _s; 00047 int _n; 00048 double _dn; 00049 double _invn; 00050 }; 00051 00052 inline const Complex& ComplexExponential::value(long int x) 00053 { 00054 if(x >= _n) { 00055 x=x % _n; 00056 } 00057 Complex& c=_cache[x]; 00058 if(c.isNull()) { 00059 switch (_s) { 00060 case Positive: 00061 c.setUnitExp(2 * M_PI * (double)x*_invn); 00062 break; 00063 case Negative: 00064 c.setUnitExp( -2 * M_PI * (double)x*_invn); 00065 break; 00066 } 00067 } 00068 return c; 00069 } 00070 00071 } // namespace QGpCoreTools 00072 00073 #endif // COMPLEXEXPONENTIAL_H
