// Copyright (C) 2011 Davis E. King (davis@dlib.net) // License: Boost Software License See LICENSE.txt for the full license. #ifndef DLIB_PROJECTION_HASh_Hh_ #define DLIB_PROJECTION_HASh_Hh_ #include "projection_hash_abstract.h" #include "../matrix.h" #include "../rand.h" #include <vector> namespace dlib { // ---------------------------------------------------------------------------------------- class projection_hash { public: projection_hash() {} template <typename EXP1, typename EXP2> projection_hash( const matrix_exp<EXP1>& proj_, const matrix_exp<EXP2>& offset_ ) : proj(proj_), offset(offset_) { // make sure requires clause is not broken DLIB_ASSERT(proj.nr() == offset.nr(), "\t projection_hash::projection_hash()" << "\n\t Invalid arguments were given to this function." << "\n\t proj.nr(): " << proj.nr() << "\n\t offset.nr(): " << offset.nr() ); } const matrix<double>& get_projection_matrix ( ) const { return proj; } const matrix<double,0,1>& get_offset_matrix ( ) const { return offset; } unsigned long num_hash_bins ( ) const { return static_cast<unsigned long>(std::pow(2.0, (double)offset.size())); } template <typename EXP> unsigned long operator() ( const matrix_exp<EXP>& v ) const { // make sure requires clause is not broken DLIB_ASSERT(is_col_vector(v) && v.size() == get_projection_matrix().nc() && v.size() > 0, "\t unsigned long projection_hash::operator()(v)" << "\n\t Invalid arguments were given to this function." << "\n\t is_col_vector(v): " << is_col_vector(v) << "\n\t get_projection_matrix().nc(): " << get_projection_matrix().nc() << "\n\t v.size(): " << v.size() ); return do_hash(proj*matrix_cast<double>(v) + offset); } private: template <typename EXP> unsigned long do_hash ( const matrix_exp<EXP>& v ) const { unsigned long h = 0; for (long i = 0; i < v.size(); ++i) { h <<= 1; if (v(i) > 0) h |= 1; } return h; } matrix<double> proj; matrix<double,0,1> offset; }; // ---------------------------------------------------------------------------------------- inline void serialize ( const projection_hash& item, std::ostream& out ) { serialize(item.get_projection_matrix(), out); serialize(item.get_offset_matrix(), out); } inline void deserialize ( projection_hash& item, std::istream& in ) { matrix<double> proj; matrix<double,0,1> offset; deserialize(proj, in); deserialize(offset, in); item = projection_hash(proj, offset); } // ---------------------------------------------------------------------------------------- } #endif // DLIB_PROJECTION_HASh_Hh_