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Optional components of Mahout which generally support interaction with third party systems,
formats, APIs, etc.
/*
* 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.mahout.utils;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.List;
import java.util.Map;
import org.apache.commons.io.Charsets;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.ToolRunner;
import org.apache.mahout.common.AbstractJob;
import org.apache.mahout.common.iterator.sequencefile.SequenceFileValueIterator;
import org.apache.mahout.math.Matrix;
import org.apache.mahout.math.MatrixWritable;
/**
* Export a Matrix in various text formats:
* * CSV file
*
* Input format: Hadoop SequenceFile with Text key and MatrixWritable value, 1 pair
* TODO:
* Needs class for key value- should not hard-code to Text.
* Options for row and column headers- stats software can be picky.
* Assumes only one matrix in a file.
*/
public final class MatrixDumper extends AbstractJob {
private MatrixDumper() { }
public static void main(String[] args) throws Exception {
ToolRunner.run(new MatrixDumper(), args);
}
@Override
public int run(String[] args) throws Exception {
addInputOption();
addOption("output", "o", "Output path", null); // AbstractJob output feature requires param
Map> parsedArgs = parseArguments(args);
if (parsedArgs == null) {
return -1;
}
String outputFile = hasOption("output") ? getOption("output") : null;
exportCSV(getInputPath(), outputFile, false);
return 0;
}
private static void exportCSV(Path inputPath, String outputFile, boolean doLabels) throws IOException {
SequenceFileValueIterator it =
new SequenceFileValueIterator<>(inputPath, true, new Configuration());
Matrix m = it.next().get();
it.close();
PrintStream ps = getPrintStream(outputFile);
String[] columnLabels = getLabels(m.numCols(), m.getColumnLabelBindings(), "col");
String[] rowLabels = getLabels(m.numRows(), m.getRowLabelBindings(), "row");
if (doLabels) {
ps.print("rowid,");
ps.print(columnLabels[0]);
for (int c = 1; c < m.numCols(); c++) {
ps.print(',' + columnLabels[c]);
}
ps.println();
}
for (int r = 0; r < m.numRows(); r++) {
if (doLabels) {
ps.print(rowLabels[0] + ',');
}
ps.print(Double.toString(m.getQuick(r,0)));
for (int c = 1; c < m.numCols(); c++) {
ps.print(",");
ps.print(Double.toString(m.getQuick(r,c)));
}
ps.println();
}
if (ps != System.out) {
ps.close();
}
}
private static PrintStream getPrintStream(String outputPath) throws IOException {
if (outputPath == null) {
return System.out;
}
File outputFile = new File(outputPath);
if (outputFile.exists()) {
outputFile.delete();
}
outputFile.createNewFile();
OutputStream os = new FileOutputStream(outputFile);
return new PrintStream(os, false, Charsets.UTF_8.displayName());
}
/**
* return the label set, sorted by matrix order
* if there are no labels, fabricate them using the starter string
* @param length
*/
private static String[] getLabels(int length, Map labels, String start) {
if (labels != null) {
return sortLabels(labels);
}
String[] sorted = new String[length];
for (int i = 1; i <= length; i++) {
sorted[i] = start + i;
}
return sorted;
}
private static String[] sortLabels(Map labels) {
String[] sorted = new String[labels.size()];
for (Map.Entry entry : labels.entrySet()) {
sorted[entry.getValue()] = entry.getKey();
}
return sorted;
}
}