Commit f908c2b0 authored by Maksim Shabunin's avatar Maksim Shabunin

Revert "Avoid obtaining several identical dimensions between two LSH sub-vectors…

Revert "Avoid obtaining several identical dimensions between two LSH sub-vectors by choosing orthogonal sub-vectors."

This reverts commit e85bacff.
parent 032c363e
...@@ -346,21 +346,13 @@ inline LshTable<unsigned char>::LshTable(unsigned int feature_size, unsigned int ...@@ -346,21 +346,13 @@ inline LshTable<unsigned char>::LshTable(unsigned int feature_size, unsigned int
mask_ = std::vector<size_t>((size_t)ceil((float)(feature_size * sizeof(char)) / (float)sizeof(size_t)), 0); mask_ = std::vector<size_t>((size_t)ceil((float)(feature_size * sizeof(char)) / (float)sizeof(size_t)), 0);
// A bit brutal but fast to code // A bit brutal but fast to code
static std::vector<size_t> indices(feature_size * CHAR_BIT); std::vector<size_t> indices(feature_size * CHAR_BIT);
for (size_t i = 0; i < feature_size * CHAR_BIT; ++i) indices[i] = i;
//Ensure the Nth bit will be selected only once among the different LshTables std::random_shuffle(indices.begin(), indices.end());
//to avoid having two different tables with signatures sharing many dimensions/many bits
if( (indices.size() == feature_size * CHAR_BIT) || (indices.size() < key_size_) )
{
indices.resize( feature_size * CHAR_BIT );
for (size_t i = 0; i < feature_size * CHAR_BIT; ++i) indices[i] = i;
std::random_shuffle(indices.begin(), indices.end());
}
// Generate a random set of order of subsignature_size_ bits // Generate a random set of order of subsignature_size_ bits
for (unsigned int i = 0; i < key_size_; ++i) { for (unsigned int i = 0; i < key_size_; ++i) {
size_t index = indices[0]; size_t index = indices[i];
indices.erase( indices.begin() );
// Set that bit in the mask // Set that bit in the mask
size_t divisor = CHAR_BIT * sizeof(size_t); size_t divisor = CHAR_BIT * sizeof(size_t);
......
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