mirror of
https://gitee.com/milvus-io/milvus.git
synced 2024-12-09 15:30:33 +08:00
63ee525bf3
Signed-off-by: shaoyue.chen <shaoyue.chen@zilliz.com>
281 lines
7.3 KiB
Go
281 lines
7.3 KiB
Go
// Licensed to the LF AI & Data foundation under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package distance
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import (
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"errors"
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"strings"
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"sync"
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)
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const (
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// L2 represents the Euclidean distance
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L2 = "L2"
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// IP represents the inner product distance
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IP = "IP"
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// HAMMING represents the hamming distance
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HAMMING = "HAMMING"
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// TANIMOTO represents the tanimoto distance
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TANIMOTO = "TANIMOTO"
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// JACCARD in string
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JACCARD = "JACCARD"
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// SUPERSTRUCTURE in string
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SUPERSTRUCTURE = "SUPERSTRUCTURE"
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// SUBSTRUCTURE in string
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SUBSTRUCTURE = "SUBSTRUCTURE"
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)
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// ValidateMetricType returns metric text or error
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func ValidateMetricType(metric string) (string, error) {
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if metric == "" {
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err := errors.New("metric type is empty")
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return "", err
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}
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m := strings.ToUpper(metric)
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if m == L2 || m == IP || m == HAMMING || m == TANIMOTO {
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return m, nil
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}
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err := errors.New("invalid metric type")
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return metric, err
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}
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// ValidateFloatArrayLength is used validate float vector length
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func ValidateFloatArrayLength(dim int64, length int) error {
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if length == 0 || int64(length)%dim != 0 {
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err := errors.New("invalid float vector length")
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return err
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}
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return nil
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}
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// CalcL2 returns the Euclidean distance of input vectors
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func CalcL2(dim int64, left []float32, lIndex int64, right []float32, rIndex int64) float32 {
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var sum float32
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lFrom := lIndex * dim
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rFrom := rIndex * dim
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for i := int64(0); i < dim; i++ {
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gap := left[lFrom+i] - right[rFrom+i]
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sum += gap * gap
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}
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return sum
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}
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// CalcIP returns the inner product distance of input vectors
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func CalcIP(dim int64, left []float32, lIndex int64, right []float32, rIndex int64) float32 {
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var sum float32
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lFrom := lIndex * dim
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rFrom := rIndex * dim
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for i := int64(0); i < dim; i++ {
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sum += left[lFrom+i] * right[rFrom+i]
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}
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return sum
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}
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// CalcFFBatch calculate the distance of @left & @right vectors in batch by given @metic, store result in @result
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func CalcFFBatch(dim int64, left []float32, lIndex int64, right []float32, metric string, result *[]float32) {
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rightNum := int64(len(right)) / dim
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for i := int64(0); i < rightNum; i++ {
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var distance float32 = -1.0
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if metric == L2 {
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distance = CalcL2(dim, left, lIndex, right, i)
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} else if metric == IP {
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distance = CalcIP(dim, left, lIndex, right, i)
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}
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(*result)[lIndex*rightNum+i] = distance
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}
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}
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// CalcFloatDistance calculate float distance by given metric
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// it will checks input, and calculate the distance concurrently
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func CalcFloatDistance(dim int64, left, right []float32, metric string) ([]float32, error) {
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if dim <= 0 {
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err := errors.New("invalid dimension")
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return nil, err
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}
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metricUpper := strings.ToUpper(metric)
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if metricUpper != L2 && metricUpper != IP {
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err := errors.New("invalid metric type")
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return nil, err
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}
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err := ValidateFloatArrayLength(dim, len(left))
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if err != nil {
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return nil, err
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}
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err = ValidateFloatArrayLength(dim, len(right))
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if err != nil {
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return nil, err
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}
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leftNum := int64(len(left)) / dim
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rightNum := int64(len(right)) / dim
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distArray := make([]float32, leftNum*rightNum)
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// Multi-threads to calculate distance. TODO: avoid too many go routines
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var waitGroup sync.WaitGroup
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CalcWorker := func(index int64) {
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CalcFFBatch(dim, left, index, right, metricUpper, &distArray)
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waitGroup.Done()
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}
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for i := int64(0); i < leftNum; i++ {
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waitGroup.Add(1)
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go CalcWorker(i)
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}
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waitGroup.Wait()
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return distArray, nil
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}
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////////////////////////////////////////////////////////////////////////////////
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// SingleBitLen returns the bit length of @dim
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func SingleBitLen(dim int64) int64 {
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if dim%8 == 0 {
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return dim
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}
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return dim + 8 - dim%8
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}
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// VectorCount counts bits by @dim & @length
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func VectorCount(dim int64, length int) int64 {
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singleBitLen := SingleBitLen(dim)
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return int64(length*8) / singleBitLen
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}
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// ValidateBinaryArrayLength validates a binary array of @dim & @length
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func ValidateBinaryArrayLength(dim int64, length int) error {
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singleBitLen := SingleBitLen(dim)
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totalBitLen := int64(length * 8)
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if length == 0 || totalBitLen%singleBitLen != 0 {
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err := errors.New("invalid binary vector length")
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return err
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}
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return nil
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}
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// CountOne count 1 of uint8
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// For 00000010, return 1
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// Fro 11111111, return 8
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func CountOne(n uint8) int32 {
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count := int32(0)
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for n != 0 {
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count++
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n = n & (n - 1)
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}
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return count
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}
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// CalcHamming calculate HAMMING distance
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func CalcHamming(dim int64, left []byte, lIndex int64, right []byte, rIndex int64) int32 {
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singleBitLen := SingleBitLen(dim)
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numBytes := singleBitLen / 8
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lFrom := lIndex * numBytes
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rFrom := rIndex * numBytes
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var hamming int32
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for i := int64(0); i < numBytes; i++ {
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var xor = left[lFrom+i] ^ right[rFrom+i]
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// The dimension "dim" may not be an integer multiple of 8
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// For example:
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// dim = 11, each vector has 2 uint8 value
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// the second uint8, only need to calculate 3 bits, the other 5 bits will be set to 0
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if i == numBytes-1 && numBytes*8 > dim {
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offset := numBytes*8 - dim
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xor = xor & (255 << offset)
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}
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hamming += CountOne(xor)
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}
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return hamming
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}
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// CalcHammingBatch calculate HAMMING distance in batch, results are in @result
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func CalcHammingBatch(dim int64, left []byte, lIndex int64, right []byte, result *[]int32) {
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rightNum := VectorCount(dim, len(right))
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for i := int64(0); i < rightNum; i++ {
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hamming := CalcHamming(dim, left, lIndex, right, i)
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(*result)[lIndex*rightNum+i] = hamming
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}
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}
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func CalcHammingDistance(dim int64, left, right []byte) ([]int32, error) {
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if dim <= 0 {
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err := errors.New("invalid dimension")
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return nil, err
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}
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err := ValidateBinaryArrayLength(dim, len(left))
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if err != nil {
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return nil, err
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}
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err = ValidateBinaryArrayLength(dim, len(right))
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if err != nil {
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return nil, err
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}
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leftNum := VectorCount(dim, len(left))
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rightNum := VectorCount(dim, len(right))
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distArray := make([]int32, leftNum*rightNum)
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// Multi-threads to calculate distance. TODO: avoid too many go routines
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var waitGroup sync.WaitGroup
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CalcWorker := func(index int64) {
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CalcHammingBatch(dim, left, index, right, &distArray)
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waitGroup.Done()
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}
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for i := int64(0); i < leftNum; i++ {
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waitGroup.Add(1)
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go CalcWorker(i)
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}
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waitGroup.Wait()
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return distArray, nil
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}
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func CalcTanimotoCoefficient(dim int64, hamming []int32) ([]float32, error) {
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if dim <= 0 || len(hamming) == 0 {
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err := errors.New("invalid input for tanimoto")
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return nil, err
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}
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array := make([]float32, len(hamming))
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for i := 0; i < len(hamming); i++ {
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if hamming[i] > int32(dim) {
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err := errors.New("invalid hamming for tanimoto")
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return nil, err
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}
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equalBits := int32(dim) - hamming[i]
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array[i] = float32(equalBits) / (float32(dim)*2 - float32(equalBits))
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}
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return array, nil
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}
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