00001 /* 00002 Copyright (C) 2008 Wei Dong <wdong@princeton.edu>. All Rights Reserved. 00003 00004 This file is part of LSHKIT. 00005 00006 LSHKIT is free software: you can redistribute it and/or modify 00007 it under the terms of the GNU General Public License as published by 00008 the Free Software Foundation, either version 3 of the License, or 00009 (at your option) any later version. 00010 00011 LSHKIT is distributed in the hope that it will be useful, 00012 but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 GNU General Public License for more details. 00015 00016 You should have received a copy of the GNU General Public License 00017 along with LSHKIT. If not, see <http://www.gnu.org/licenses/>. 00018 */ 00019 00025 #ifndef __LSHKIT_KERNEL__ 00026 #define __LSHKIT_KERNEL__ 00027 00028 // This file implements some common kernel functions. 00029 00030 #include <functional> 00031 00032 namespace lshkit { namespace kernel { 00033 00035 template <typename T /* real type */> 00036 class dot : public std::binary_function<const T*, const T*, float> 00037 { 00038 unsigned dim_; 00039 public: 00040 dot (unsigned dim) : dim_(dim) {} 00041 float operator () (const T *first1, const T *first2) const 00042 { 00043 float r = 0.0; 00044 for (unsigned i = 0; i < dim_; ++i) 00045 { 00046 r += first1[i] * first2[i]; 00047 } 00048 return r; 00049 } 00050 }; 00051 00052 00053 }} 00054 00055 #endif 00056 00057