
org.apache.flink.ml.feature.idf.IDFModelData Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.ml.feature.idf;
import org.apache.flink.api.common.serialization.Encoder;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.typeutils.base.LongSerializer;
import org.apache.flink.api.common.typeutils.base.array.LongPrimitiveArraySerializer;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.connector.file.src.reader.SimpleStreamFormat;
import org.apache.flink.core.fs.FSDataInputStream;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataInputViewStreamWrapper;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
import org.apache.flink.ml.linalg.DenseVector;
import org.apache.flink.ml.linalg.typeinfo.DenseVectorSerializer;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.api.internal.TableImpl;
import java.io.EOFException;
import java.io.IOException;
import java.io.OutputStream;
/**
* Model data of {@link IDFModel}.
*
* This class also provides methods to convert model data from Table to a data stream, and
* classes to save/load model data.
*/
public class IDFModelData {
/** Inverse document frequency for all terms. */
public DenseVector idf;
/** Document frequency for all terms after filtering out infrequent terms. */
public long[] docFreq;
/** Number of docs in the training set. */
public long numDocs;
public IDFModelData() {}
public IDFModelData(DenseVector idf, long[] docFreq, long numDocs) {
this.idf = idf;
this.docFreq = docFreq;
this.numDocs = numDocs;
}
/**
* Converts the table model to a data stream.
*
* @param modelDataTable The table model data.
* @return The data stream model data.
*/
public static DataStream getModelDataStream(Table modelDataTable) {
StreamTableEnvironment tEnv =
(StreamTableEnvironment) ((TableImpl) modelDataTable).getTableEnvironment();
return tEnv.toDataStream(modelDataTable)
.map(x -> new IDFModelData(x.getFieldAs(0), x.getFieldAs(1), x.getFieldAs(2)));
}
/** Encoder for {@link IDFModelData}. */
public static class ModelDataEncoder implements Encoder {
private final DenseVectorSerializer denseVectorSerializer = new DenseVectorSerializer();
@Override
public void encode(IDFModelData modelData, OutputStream outputStream) throws IOException {
DataOutputView dataOutputView = new DataOutputViewStreamWrapper(outputStream);
denseVectorSerializer.serialize(modelData.idf, dataOutputView);
LongPrimitiveArraySerializer.INSTANCE.serialize(modelData.docFreq, dataOutputView);
LongSerializer.INSTANCE.serialize(modelData.numDocs, dataOutputView);
}
}
/** Decoder for {@link IDFModelData}. */
public static class ModelDataDecoder extends SimpleStreamFormat {
@Override
public Reader createReader(Configuration config, FSDataInputStream stream) {
return new Reader() {
private final DenseVectorSerializer denseVectorSerializer =
new DenseVectorSerializer();
@Override
public IDFModelData read() throws IOException {
DataInputView source = new DataInputViewStreamWrapper(stream);
try {
DenseVector idf = denseVectorSerializer.deserialize(source);
long[] docFreq = LongPrimitiveArraySerializer.INSTANCE.deserialize(source);
long numDocs = LongSerializer.INSTANCE.deserialize(source);
return new IDFModelData(idf, docFreq, numDocs);
} catch (EOFException e) {
return null;
}
}
@Override
public void close() throws IOException {
stream.close();
}
};
}
@Override
public TypeInformation getProducedType() {
return TypeInformation.of(IDFModelData.class);
}
}
}