nsg 算法

 

//
// Created by 付聪 on 2017/6/21.
//

#include <efanna2e/index_nsg.h>
#include <efanna2e/util.h>

void load_data(char* filename, float*& data, unsigned& num,unsigned& dim){// load data with sift10K pattern
  std::ifstream in(filename, std::ios::binary);
  if(!in.is_open()){std::cout<<"open file error"<<std::endl;exit(-1);}
  in.read((char*)&dim,4);
  std::cout<<"data dimension: "<<dim<<std::endl;
  in.seekg(0,std::ios::end);
  std::ios::pos_type ss = in.tellg();
  size_t fsize = (size_t)ss;
  num = (unsigned)(fsize / (dim+1) / 4);
  data = new float[num * dim * sizeof(float)];

  in.seekg(0,std::ios::beg);
  for(size_t i = 0; i < num; i++){
    in.seekg(4,std::ios::cur);
    in.read((char*)(data+i*dim),dim*4);
  }
  in.close()