Milena (Olena)
User documentation 2.0a Id
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00001 // Copyright (C) 2010 EPITA Research and Development Laboratory (LRDE) 00002 // 00003 // This file is part of Olena. 00004 // 00005 // Olena is free software: you can redistribute it and/or modify it under 00006 // the terms of the GNU General Public License as published by the Free 00007 // Software Foundation, version 2 of the License. 00008 // 00009 // Olena is distributed in the hope that it will be useful, 00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00012 // General Public License for more details. 00013 // 00014 // You should have received a copy of the GNU General Public License 00015 // along with Olena. If not, see <http://www.gnu.org/licenses/>. 00016 // 00017 // As a special exception, you may use this file as part of a free 00018 // software project without restriction. Specifically, if other files 00019 // instantiate templates or use macros or inline functions from this 00020 // file, or you compile this file and link it with other files to produce 00021 // an executable, this file does not by itself cause the resulting 00022 // executable to be covered by the GNU General Public License. This 00023 // exception does not however invalidate any other reasons why the 00024 // executable file might be covered by the GNU General Public License. 00025 00026 #ifndef MLN_FUN_N2V_WHITE_GAUSSIAN_HH 00027 # define MLN_FUN_N2V_WHITE_GAUSSIAN_HH 00028 00032 00033 # include <cstdlib> 00034 # include <ctime> 00035 00036 # include <mln/core/concept/function.hh> 00037 # include <mln/math/sqrt.hh> 00038 00039 00040 namespace mln 00041 { 00042 00043 namespace fun 00044 { 00045 00046 namespace n2v 00047 { 00048 00055 template <typename V> 00056 struct white_gaussian : Function_n2v< white_gaussian<V> > 00057 { 00058 typedef V result; 00059 00060 white_gaussian(double sigma_); 00061 V operator()() const; 00062 00063 double sigma; 00064 }; 00065 00066 00067 # ifndef MLN_INCLUDE_ONLY 00068 00069 00070 template <typename V> 00071 white_gaussian<V>::white_gaussian(double sigma_) 00072 : sigma(sigma_) 00073 { 00074 srand(time(0)); 00075 } 00076 00077 00078 template <typename V> 00079 V white_gaussian<V>::operator()() const 00080 { 00081 double X = 0; 00082 for (int i = 1; i < 50; ++i) 00083 { 00084 double U = rand() / (float)RAND_MAX; 00085 X = X + U; 00086 } 00087 00088 X = X - 25.f; /* set mean to 0 */ 00089 X = X * math::sqrt(12 / 50.f); /* adjust variance to 1 */ 00090 00091 return sigma * X; 00092 }; 00093 00094 00095 # endif // ! MLN_INCLUDE_ONLY 00096 00097 } // end of namespace mln::fun::n2v 00098 00099 } // end of namespace mln::fun 00100 00101 } // end of namespace mln 00102 00103 00104 #endif // ! MLN_FUN_N2V_WHITE_GAUSSIAN_HH