Java 类名：com.alibaba.alink.operator.stream.clustering.LdaPredictStreamOp
Python 类名：LdaPredictStreamOp

功能介绍

LDA(Latent Dirichlet allocation)是一种主题模型。LDA是一种非监督机器学习技术，可以用来识别大规模文档集（document collection）或语料库（corpus）中潜藏的主题信息。它采用了词袋（bag of words）的方法，这种方法将每一篇文档视为一个词频向量，从而将文本信息转化为了易于建模的数字信息。但是词袋方法没有考虑词与词之间的顺序，这简化了问题的复杂性，同时也为模型的改进提供了契机。每一篇文档代表了一些主题所构成的一个概率分布，而每一个主题又代表了很多单词所构成的一个概率分布。
它将文档集中每篇文档的主题按照概率分布的形式给出，同时它是一种无监督学习算法，在训练时不需要手工标注的训练集，需要的仅仅是文档集以及指定主题的数量k即可。
LDA功能包含LDA训练和LDA预测(批和流)以及pipeline。

参数说明

| 名称 | 中文名称 | 描述 | 类型 | 是否必须？ | 取值范围 | 默认值 | | —- | —- | —- | —- | —- | —- | —- |

| predictionCol | 预测结果列名 | 预测结果列名 | String | ✓ | | |

| selectedCol | 选中的列名 | 计算列对应的列名 | String | ✓ | 所选列类型为 [BIGDECIMAL, BIGINTEGER, BYTE, DOUBLE, FLOAT, INTEGER, LONG, SHORT] | |

| modelFilePath | 模型的文件路径 | 模型的文件路径 | String | | | null |

| predictionDetailCol | 预测详细信息列名 | 预测详细信息列名 | String | | | |

| reservedCols | 算法保留列名 | 算法保留列 | String[] | | | null |

| numThreads | 组件多线程线程个数 | 组件多线程线程个数 | Integer | | | 1 |

| modelStreamFilePath | 模型流的文件路径 | 模型流的文件路径 | String | | | null |

| modelStreamScanInterval | 扫描模型路径的时间间隔 | 描模型路径的时间间隔，单位秒 | Integer | | | 10 |

| modelStreamStartTime | 模型流的起始时间 | 模型流的起始时间。默认从当前时刻开始读。使用yyyy-mm-dd hh:mm:ss.fffffffff格式，详见Timestamp.valueOf(String s) | String | | | null |

代码示例

Python 代码

  1. from pyalink.alink import *
  3. import pandas as pd
  5. useLocalEnv(1)
  7. df = pd.DataFrame([
  8.     ["a b b c c c c c c e e f f f g h k k k"], 
  9.     ["a b b b d e e e h h k"], 
  10.     ["a b b b b c f f f f g g g g g g g g g i j j"], 
  11.     ["a a b d d d g g g g g i i j j j k k k k k k k k k"], 
  12.     ["a a a b c d d d d d d d d d e e e g g j k k k"], 
  13.     ["a a a a b b d d d e e e e f f f f f g h i j j j j"], 
  14.     ["a a b d d d g g g g g i i j j k k k k k k k k k"], 
  15.     ["a b c d d d d d d d d d e e f g g j k k k"], 
  16.     ["a a a a b b b b d d d e e e e f f g h h h"], 
  17.     ["a a b b b b b b b b c c e e e g g i i j j j j j j j k k"], 
  18.     ["a b c d d d d d d d d d f f g g j j j k k k"], 
  19.     ["a a a a b e e e e f f f f f g h h h j"],
  20. ])
  22. inOp = BatchOperator.fromDataframe(df, schemaStr="doc string")
  23. inOp2 = StreamOperator.fromDataframe(df, schemaStr="doc string")
  25. ldaTrain = LdaTrainBatchOp()\
  26.             .setSelectedCol("doc")\
  27.             .setTopicNum(6)\
  28.             .setMethod("online")\
  29.             .setSubsamplingRate(1.0)\
  30.             .setOptimizeDocConcentration(True)\
  31.             .setNumIter(20)
  33. ldaPredict = LdaPredictBatchOp()\
  34.     .setPredictionCol("pred")\
  35.     .setSelectedCol("doc")
  37. model = ldaTrain.linkFrom(inOp)
  38. ldaPredict.linkFrom(model, inOp)
  40. model.lazyPrint(10)
  41. ldaPredict.print()
  43. ldaPredictS = LdaPredictStreamOp(model)\
  44.     .setPredictionCol("pred")\
  45.     .setSelectedCol("doc")\
  46.     .linkFrom(inOp2)
  48. ldaPredictS.print()
  50. StreamOperator.execute()

Java 代码

  1. import org.apache.flink.types.Row;
  3. import com.alibaba.alink.operator.batch.BatchOperator;
  4. import com.alibaba.alink.operator.batch.clustering.LdaPredictBatchOp;
  5. import com.alibaba.alink.operator.batch.clustering.LdaTrainBatchOp;
  6. import com.alibaba.alink.operator.batch.source.MemSourceBatchOp;
  7. import com.alibaba.alink.operator.stream.StreamOperator;
  8. import com.alibaba.alink.operator.stream.clustering.LdaPredictStreamOp;
  9. import com.alibaba.alink.operator.stream.source.MemSourceStreamOp;
  10. import org.junit.Test;
  12. import java.util.Arrays;
  13. import java.util.List;
  15. public class LdaPredictStreamOpTest {
  16.     @Test
  17.     public void testLdaPredictStreamOp() throws Exception {
  18.         List <Row> df = Arrays.asList(
  19.             Row.of("a b b c c c c c c e e f f f g h k k k"),
  20.             Row.of("a b b b d e e e h h k"),
  21.             Row.of("a b b b b c f f f f g g g g g g g g g i j j"),
  22.             Row.of("a a b d d d g g g g g i i j j j k k k k k k k k k"),
  23.             Row.of("a a a b c d d d d d d d d d e e e g g j k k k"),
  24.             Row.of("a a a a b b d d d e e e e f f f f f g h i j j j j"),
  25.             Row.of("a a b d d d g g g g g i i j j k k k k k k k k k"),
  26.             Row.of("a b c d d d d d d d d d e e f g g j k k k"),
  27.             Row.of("a a a a b b b b d d d e e e e f f g h h h"),
  28.             Row.of("a a b b b b b b b b c c e e e g g i i j j j j j j j k k"),
  29.             Row.of("a b c d d d d d d d d d f f g g j j j k k k"),
  30.             Row.of("a a a a b e e e e f f f f f g h h h j")
  31.         );
  32.         BatchOperator <?> inOp = new MemSourceBatchOp(df, "doc string");
  33.         StreamOperator <?> inOp2 = new MemSourceStreamOp(df, "doc string");
  34.         BatchOperator <?> ldaTrain = new LdaTrainBatchOp()
  35.             .setSelectedCol("doc")
  36.             .setTopicNum(6)
  37.             .setMethod("online")
  38.             .setSubsamplingRate(1.0)
  39.             .setOptimizeDocConcentration(true)
  40.             .setNumIter(20);
  41.         BatchOperator <?> ldaPredict = new LdaPredictBatchOp()
  42.             .setPredictionCol("pred")
  43.             .setSelectedCol("doc");
  44.         BatchOperator <?> model = ldaTrain.linkFrom(inOp);
  45.         ldaPredict.linkFrom(model, inOp);
  46.         model.lazyPrint(10);
  47.         ldaPredict.print();
  48.         StreamOperator <?> ldaPredictS = new LdaPredictStreamOp(model)
  49.             .setPredictionCol("pred")
  50.             .setSelectedCol("doc")
  51.             .linkFrom(inOp2);
  52.         ldaPredictS.print();
  53.         StreamOperator.execute();
  54.     }
  55. }

运行结果

模型结果

| model_id | model_info | | —- | —- |

| 0 | {“logPerplexity”:”3.7090449161397796”,”betaArray”:”[0.16666666666666666,0.16666666666666666,0.16666666666666666,0.16666666666666666,0.16666666666666666,0.16666666666666666]”,”logLikelihood”:”-964.3516781963427”,”method”:””online””,”alphaArray”:”[0.13821318741806757,0.14883947846014303,0.11751772860080838,0.11649338902896737,0.1503735753641805,0.12383960905322638]”,”topicNum”:”6”,”vocabularySize”:”11”} |

| 1048576 | {“m”:6,”n”:11,”data”:[6125.275647735944,5541.830400832857,5277.404107556518,5575.307666756267,5738.822977932333,5664.141524765102,5183.8663148472615,6286.886714218059,5159.4834022615505,5965.45851687814,5785.616901302167,5558.164928383525,5290.881194601821,5849.766053667748,5595.238710003511,5709.172846472106,5367.427910628795,6967.997740551021,5688.8764262580735,4955.8174077887725,4940.593716098454,5435.785995518678,6359.043301395186,4992.933732368455,5164.467086144761,6624.6072909374125,6911.005911971013,6239.327690548231,5908.580210537792,6090.679944041717,4491.439930702308,5785.921888708801,4648.954813378507,5714.129075228494,6200.167117921488,5223.186458407328,5560.911614536643,5141.113565996373,6043.809469077941,7092.299303765094,6408.739229185271,5851.449695701356,4518.178684615466,5946.483529384942,5633.526524470202,5538.4345859137275,5983.901197676244,5587.210556929512,6050.024468817716,4965.114090486532,4634.277477990217,5692.989466800378,5462.485467579785,4841.301836486494,5117.962076960599,4980.381226902301,5186.706443620538,6608.121037167229,5926.302505211329,6106.240714316094,5474.117007346719,4977.005342253029,5871.2842682743185,4842.798396244806,4810.0086663355705,5468.469136036559]} |

| 2097152 | {“f0”:”d”,”f1”:0.36772478012531734,”f2”:0} |

| 3145728 | {“f0”:”k”,”f1”:0.36772478012531734,”f2”:1} |

| 4194304 | {“f0”:”f”,”f1”:0.4855078157817008,”f2”:7} |

| 5242880 | {“f0”:”c”,”f1”:0.6190392084062235,”f2”:8} |

| 6291456 | {“f0”:”h”,”f1”:0.7731898882334817,”f2”:9} |

| 7340032 | {“f0”:”i”,”f1”:0.7731898882334817,”f2”:10} |

| 8388608 | {“f0”:”g”,”f1”:0.08004270767353636,”f2”:2} |

| 9437184 | {“f0”:”b”,”f1”:0.0,”f2”:3} |

| 10485760 | {“f0”:”a”,”f1”:0.0,”f2”:4} |

| 11534336 | {“f0”:”e”,”f1”:0.36772478012531734,”f2”:5} |

| 12582912 | {“f0”:”j”,”f1”:0.26236426446749106,”f2”:6} |

预测结果

| id | libsvm | pred | | —- | —- | —- |

| 0 | a b b c c c c c c e e f f f g h k k k | 0 |

| 1 | a b b b d e e e h h k | 4 |

| 2 | a b b b b c f f f f g g g g g g g g g i j j | 5 |

| 3 | a a b d d d g g g g g i i j j j k k k k k k k k k | 1 |

| 4 | a a a b c d d d d d d d d d e e e g g j k k k | 1 |

| 5 | a a a a b b d d d e e e e f f f f f g h i j j j j | 2 |

| 6 | a a b d d d g g g g g i i j j k k k k k k k k k | 1 |

| 7 | a b c d d d d d d d d d e e f g g j k k k | 0 |

| 8 | a a a a b b b b d d d e e e e f f g h h h | 4 |

| 9 | a a b b b b b b b b c c e e e g g i i j j j j j j j k k | 4 |

| 10 | a b c d d d d d d d d d f f g g j j j k k k | 0 |

| 11 | a a a a b e e e e f f f f f g h h h j | 1 |