字符串近似最近邻预测 (StringApproxNearestNeighborPredictBatchOp)

Java 类名：com.alibaba.alink.operator.batch.similarity.StringApproxNearestNeighborPredictBatchOp
Python 类名：StringApproxNearestNeighborPredictBatchOp

功能介绍

该功能由训练和预测组成，支持计算1. 求最近邻topN 2. 求radius范围内的邻居。该功能由预测时候的topN和radius参数控制, 如果填写了topN，则输出最近邻，如果填写了radius，则输出radius范围内的邻居。
SimhashHamming（SimHash_Hamming_Distance)相似度=1-距离/64.0，应选择metric的参数为SIMHASH_HAMMING_SIM。
MinHash应选择metric的参数为MINHASH_SIM。
Jaccard应选择metric的参数为JACCARD_SIM。

参数说明

代码示例

Python 代码

from pyalink.alink import *
import pandas as pd
useLocalEnv(1)
df = pd.DataFrame([
    [0, "abcde", "aabce"],
    [1, "aacedw", "aabbed"],
    [2, "cdefa", "bbcefa"],
    [3, "bdefh", "ddeac"],
    [4, "acedm", "aeefbc"]
])
inOp = BatchOperator.fromDataframe(df, schemaStr='id long, text1 string, text2 string')
train = StringApproxNearestNeighborTrainBatchOp().setIdCol("id").setSelectedCol("text1").setMetric("SIMHASH_HAMMING_SIM").linkFrom(inOp)
predict = StringApproxNearestNeighborPredictBatchOp().setSelectedCol("text2").setTopN(3).linkFrom(train, inOp)
predict.print()

Java 代码

import org.apache.flink.types.Row;
import com.alibaba.alink.operator.batch.BatchOperator;
import com.alibaba.alink.operator.batch.similarity.StringApproxNearestNeighborPredictBatchOp;
import com.alibaba.alink.operator.batch.similarity.StringApproxNearestNeighborTrainBatchOp;
import com.alibaba.alink.operator.batch.source.MemSourceBatchOp;
import org.junit.Test;
import java.util.Arrays;
import java.util.List;
public class StringApproxNearestNeighborPredictBatchOpTest {
    @Test
    public void testStringApproxNearestNeighborPredictBatchOp() throws Exception {
        List <Row> df = Arrays.asList(
            Row.of(0, "abcde", "aabce"),
            Row.of(1, "aacedw", "aabbed"),
            Row.of(2, "cdefa", "bbcefa"),
            Row.of(3, "bdefh", "ddeac"),
            Row.of(4, "acedm", "aeefbc")
        );
        BatchOperator <?> inOp = new MemSourceBatchOp(df, "id int, text1 string, text2 string");
        BatchOperator <?> train = new StringApproxNearestNeighborTrainBatchOp().setIdCol("id").setSelectedCol("text1")
            .setMetric("SIMHASH_HAMMING_SIM").linkFrom(inOp);
        BatchOperator <?> predict = new StringApproxNearestNeighborPredictBatchOp().setSelectedCol("text2").setTopN(3)
            .linkFrom(train, inOp);
        predict.print();
    }
}

运行结果