Ejemplo n.º 1
0
inline void preparePointAdding(PRNearNeighborStructT nnStruct, PUHashStructureT uhash, PPointT point){
  ASSERT(nnStruct != NULL);
  ASSERT(uhash != NULL);
  ASSERT(point != NULL);

  //TIMEV_START(timeComputeULSH);
  for(IntT d = 0; d < nnStruct->dimension; d++){
    nnStruct->reducedPoint[d] = point->coordinates[d] / nnStruct->parameterR;
  }

  
  // Compute all ULSH functions.
  for(IntT i = 0; i < nnStruct->nHFTuples; i++){
    computeULSH(nnStruct, i, nnStruct->reducedPoint, nnStruct->pointULSHVectors[i]);
  }
	
  //printIntVector("pointULSHVectors", 10, (int *) nnStruct->pointULSHVectors[0]);
  // Compute data for <precomputedHashesOfULSHs>.
  if (USE_SAME_UHASH_FUNCTIONS) {
    for(IntT i = 0; i < nnStruct->nHFTuples; i++){
		//if (i == 0) printIntVector("masterHash", 10, (int*) uhash->mainHashA);
      precomputeUHFsForULSH(uhash, nnStruct->pointULSHVectors[i], nnStruct->hfTuplesLength, nnStruct->precomputedHashesOfULSHs[i]);
    }
  }

  //TIMEV_END(timeComputeULSH);
}
inline void preparePointAdding(PRNearNeighborStructT nnStruct, PUHashStructureT uhash, PPointT point)
{
//输入: nnntstuct结构体(降维的向量),  uhash(hash的两个主副向量)  特征点
//操作:先计算点的降维结果,然后计算两个hash索引值 保存到nnStruct->precomputedHashesOfULSHs
//功能,提前计算好每个点的hash表索引值

    //根据传入的多维point。
    //计算对应每个hash表的降维=》hash值,
    //存入了nnStruct->precomputedHashesOfULSHs
    ASSERT(nnStruct != NULL);
    ASSERT(uhash != NULL);
    ASSERT(point != NULL);

    TIMEV_START(timeComputeULSH);
    for(IntT d = 0; d < nnStruct->dimension; d++) {
        nnStruct->reducedPoint[d] = point->coordinates[d] / nnStruct->parameterR;
    }


    //降维
    // Compute all ULSH functions.
    for(IntT i = 0; i < nnStruct->nHFTuples; i++) { //nHFTuples是元组个数,
        //求出nnStruct->reducedPoint向量和多个hansh映射后的值, 对于每个hash:  a。v+b 除以 r
        //结果返回到pointULSHVectors【】 向量上
        //pointULSHVectors【i】就是 第一步降维后的向量值
        computeULSH(nnStruct, i, nnStruct->reducedPoint, nnStruct->pointULSHVectors[i]);
    }

    //模hash
    // Compute data for <precomputedHashesOfULSHs>.
    if (USE_SAME_UHASH_FUNCTIONS) {
        for(IntT i = 0; i < nnStruct->nHFTuples; i++) {
            precomputeUHFsForULSH(uhash, nnStruct->pointULSHVectors[i], nnStruct->hfTuplesLength, nnStruct->precomputedHashesOfULSHs[i]);
            //根据降维后的结果向量:pointULSHVectors【i】  计算两个hash值,存入precomputedHashesOfULSHs【i】
        }
    }

    TIMEV_END(timeComputeULSH);
}