Java Matrix类代码示例

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/***
 * PPCA: sequential PPCA based on the paper from Tipping and Bishop
 * 
 * @param conf
 *          the configuration
 * @param input
 *          the path to the input matrix Y
 * @param output
 *          the output path (not used currently)
 * @param nRows
 *          number or rows in Y
 * @param nCols
 *          number of columns in Y
 * @param nPCs
 *          number of desired principal components
 * @return the error
 * @throws Exception
 */
double runSequential(Configuration conf, Path input, Path output,
    final int nRows, final int nCols, final int nPCs) throws Exception {
  Matrix centralY = new DenseMatrix(nRows, nCols);
  FileSystem fs = FileSystem.get(input.toUri(), conf);
  if (fs.listStatus(input).length == 0) {
    System.err.println("No file under " + input);
    return 0;
  }
  int row = 0;
  for (VectorWritable vw : new SequenceFileDirValueIterable<VectorWritable>(
      input, PathType.LIST, null, conf)) {
    centralY.assignRow(row, vw.get());
    row++;
  }
  Matrix centralC = PCACommon.randomMatrix(nCols, nPCs);
  double ss = PCACommon.randSS();
  InitialValues initVal = new InitialValues(centralC, ss);
  // Matrix sampledYe = sample(centralY);
  // runSequential(conf, sampledYe, initVal, 100);
  double error = runSequential(conf, centralY, initVal, 100);
  return error;
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * PPCA: sequential PPCA based on the matlab implementation of Jacob Verbeek
 * 
 * @param conf
 *          the configuration
 * @param input
 *          the path to the input matrix Y
 * @param output
 *          the output path (not used currently)
 * @param nRows
 *          number or rows in Y
 * @param nCols
 *          number of columns in Y
 * @param nPCs
 *          number of desired principal components
 * @return the error
 * @throws Exception
 */
double runSequential_JacobVersion(Configuration conf, Path input,
    Path output, final int nRows, final int nCols, final int nPCs) throws Exception {
  Matrix centralY = new DenseMatrix(nRows, nCols);
  FileSystem fs = FileSystem.get(input.toUri(), conf);
  if (fs.listStatus(input).length == 0) {
    System.err.println("No file under " + input);
    return 0;
  }
  int row = 0;
  for (VectorWritable vw : new SequenceFileDirValueIterable<VectorWritable>(
      input, PathType.LIST, null, conf)) {
    centralY.assignRow(row, vw.get());
    row++;
  }
  Matrix C = PCACommon.randomMatrix(nCols, nPCs);
  double ss = PCACommon.randSS();
  InitialValues initVal = new InitialValues(C, ss);
  double error = runSequential_JacobVersion(conf, centralY, initVal, 100);
  return error;
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Computes {@code p(topic x|term a, document i)} distributions given input document {@code i}.
 * {@code pTGT[x][a]} is the (un-normalized) {@code p(x|a,i)}, or if docTopics is {@code null},
 * {@code p(a|x)} (also un-normalized).
 *
 * @param document doc-term vector encoding {@code w(term a|document i)}.
 * @param docTopics {@code docTopics[x]} is the overall weight of topic {@code x} in given
 *          document. If {@code null}, a topic weight of {@code 1.0} is used for all topics.
 * @param termTopicDist storage for output {@code p(x|a,i)} distributions.
 */
private void pTopicGivenTerm(Vector document, Vector docTopics, Matrix termTopicDist) {
  // for each topic x
  for (int x = 0; x < numTopics; x++) {
    // get p(topic x | document i), or 1.0 if docTopics is null
    double topicWeight = docTopics == null ? 1.0 : docTopics.get(x);
    // get w(term a | topic x)
    Vector topicTermRow = topicTermCounts.viewRow(x);
    // get \sum_a w(term a | topic x)
    double topicSum = topicSums.get(x);
    // get p(topic x | term a) distribution to update
    Vector termTopicRow = termTopicDist.viewRow(x);

    // for each term a in document i with non-zero weight
    Iterator<Vector.Element> it = document.iterateNonZero();
    while (it.hasNext()) {
      Vector.Element e = it.next();
      int termIndex = e.index();

      // calc un-normalized p(topic x | term a, document i)
      double termTopicLikelihood = (topicTermRow.get(termIndex) + eta) * (topicWeight + alpha) / (topicSum + eta * numTerms);
      termTopicRow.set(termIndex, termTopicLikelihood);
    }
  }
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
static void writeMatrix(Matrix origMatrix,
     Path outPath, Path tmpPath, String label) throws IOException {
   Configuration conf = new Configuration();
   Path outputDir = new Path(outPath, label + origMatrix.numRows() + "x"
       + origMatrix.numCols());
   FileSystem fs = FileSystem.get(outputDir.toUri(), conf);
   if (!fs.exists(outputDir)) {
     Path outputFile = new Path(outputDir, "singleSliceMatrix");
     SequenceFile.Writer writer = new SequenceFile.Writer(fs, conf,
         outputFile, IntWritable.class, VectorWritable.class);
     VectorWritable vectorWritable = new VectorWritable();
     try {
       for (int r = 0; r < origMatrix.numRows(); r++) {
         Vector vector = origMatrix.viewRow(r);
         vectorWritable.set(vector);
         writer.append(new IntWritable(r), vectorWritable);
       }
     } finally {
       writer.close();
     }
   } else {
     log.warn("----------- Skip matrix " + outputDir + " - already exists");
   }
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Computes the inverse covariance from the input covariance matrix given in input.
 *
 * @param m A covariance matrix.
 * @throws IllegalArgumentException if <tt>eigen values equal to 0 found</tt>.
 */
public void setCovarianceMatrix(Matrix m) {
  if (m.numRows() != m.numCols()) {
    throw new CardinalityException(m.numRows(), m.numCols());
  }
  // See http://www.mlahanas.de/Math/svd.htm for details,
  // which specifically details the case of covariance matrix inversion
  // Complexity: O(min(nm2,mn2))
  SingularValueDecomposition svd = new SingularValueDecomposition(m);
  Matrix sInv = svd.getS();
  // Inverse Diagonal Elems
  for (int i = 0; i < sInv.numRows(); i++) {
    double diagElem = sInv.get(i, i);
    if (diagElem > 0.0) {
      sInv.set(i, i, 1 / diagElem);
    } else {
      throw new IllegalStateException("Eigen Value equals to 0 found.");
    }
  }
  inverseCovarianceMatrix = svd.getU().times(sInv.times(svd.getU().transpose()));
  Preconditions.checkArgument(inverseCovarianceMatrix != null, "inverseCovarianceMatrix not initialized");
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
public Matrix getMatrix() {
  int length = confusionMatrix.length;
  Matrix m = new DenseMatrix(length, length);
  for (int r = 0; r < length; r++) {
    for (int c = 0; c < length; c++) {
      m.set(r, c, confusionMatrix[r][c]);
    }
  }
  Map<String,Integer> labels = Maps.newHashMap();
  for (Map.Entry<String, Integer> entry : labelMap.entrySet()) {
    labels.put(entry.getKey(), entry.getValue());
  }
  m.setRowLabelBindings(labels);
  m.setColumnLabelBindings(labels);
  return m;
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/***
 * Mi = (Yi-Ym)' x (Xi-Xm) = Yi' x (Xi-Xm) - Ym' x (Xi-Xm)
 * 
 * M = Sum(Mi) = Sum(Yi' x (Xi-Xm)) - Ym' x (Sum(Xi)-N*Xm)
 * 
 * The second part is done in this function
 */

public static Matrix updateXtXAndYtx(Matrix realCentralYtx,
		Vector realCentralSumX, Vector ym, Vector xm, int nRows) {
	for (int yRow = 0; yRow < ym.size(); yRow++) {
		double scale = ym.getQuick(yRow);
		for (int xCol = 0; xCol < realCentralSumX.size(); xCol++) {
			double centeredValue = realCentralSumX.getQuick(xCol) - nRows
					* xm.getQuick(xCol);
			double currValue = realCentralYtx.getQuick(yRow, xCol);
			currValue -= centeredValue * scale;
			realCentralYtx.setQuick(yRow, xCol, currValue);
		}
	}
	return realCentralYtx;
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * multiply a sparse vector by a matrix
 * @param sparseVector
 * @param matrix
 * @param resArray
 */

static void sparseVectorTimesMatrix(org.apache.spark.mllib.linalg.Vector sparseVector, Matrix matrix,
		double[] resArray) {
	int matrixCols = matrix.numCols();
	int[] indices;
	for (int col = 0; col < matrixCols; col++) 
	{
		indices=((SparseVector)sparseVector).indices();
		int index = 0, i=0;
		double value = 0;
		double dotRes = 0;
		for(i=0; i <indices.length; i++)
		{
			index=indices[i];
			value=sparseVector.apply(index);
			dotRes += matrix.getQuick(index,col) * value;
		}
		resArray[col] = dotRes;
	}
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Convert org.apache.mahout.math.Matrix object to org.apache.spark.mllib.linalg.Matrix object to be used in Spark Programs
 */
public static org.apache.spark.mllib.linalg.Matrix convertMahoutToSparkMatrix(Matrix mahoutMatrix)
{
	int rows=mahoutMatrix.numRows();
	int cols=mahoutMatrix.numCols();
	int arraySize= rows*cols;
	int arrayIndex=0;
	double[] colMajorArray= new double[arraySize];
	for(int i=0;i<cols; i++)
	{
		for(int j=0; j< rows; j++)
		{
			colMajorArray[arrayIndex] = mahoutMatrix.get(j, i);
			arrayIndex++;
		}
	}
	org.apache.spark.mllib.linalg.Matrix sparkMatrix = Matrices.dense(rows, cols, colMajorArray);
	return sparkMatrix;
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Writes the matrix to file based on the given format format
 */
public static void printMatrixToFile(org.apache.spark.mllib.linalg.Matrix m, OutputFormat format, String outputPath) {
	String outputFilePath=outputPath+ File.separator + "PCs.txt";
	switch(format)
	{
		case DENSE:
			printMatrixInDenseTextFormat(m,outputFilePath);
			break;
		case LIL:
			printMatrixInListOfListsFormat(m,outputFilePath);
			break;
		case COO:
			printMatrixInCoordinateFormat(m,outputFilePath);
			break;	
	}
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Writes the matrix in a Dense text format
 */

public static void printMatrixInDenseTextFormat(org.apache.spark.mllib.linalg.Matrix m, String outputPath) {
	try {
		FileWriter fileWriter = new FileWriter(outputPath);
		PrintWriter printWriter= new PrintWriter(fileWriter);
		 for(int i=0; i < m.numRows(); i++)
		 {
			for(int j=0; j < m.numCols(); j++)
			{
				printWriter.print(m.apply(i, j) + " ");
			}
			printWriter.println();
		}
		printWriter.close();
		fileWriter.close();
	}
	catch (Exception e) {
		Log.error("Output file " + outputPath + " not found ");
	}	
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
/**
 * Writes the matrix in a Coordinate list (COO) format
 */
public static void printMatrixInCoordinateFormat(org.apache.spark.mllib.linalg.Matrix m, String outputPath) {
	try
	{
		FileWriter fileWriter = new FileWriter(outputPath);
		PrintWriter printWriter= new PrintWriter(fileWriter);
		double val;
		for(int i=0; i < m.numRows(); i++)
		 {
			for(int j=0; j < m.numCols(); j++)
			{
				val=m.apply(i, j);
				if(val!=0)
					printWriter.println(i + "," + j + "," + val);
			}
		}
		printWriter.close();
		fileWriter.close();
	}
	catch (Exception e) {
		Log.error("Output file " + outputPath + " not found ");
	}
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
public TopicModel(Matrix topicTermCounts, Vector topicSums, double eta, double alpha,
  String[] dictionary, int numThreads, double modelWeight) {
  this.dictionary = dictionary;
  this.topicTermCounts = topicTermCounts;
  this.topicSums = topicSums;
  this.numTopics = topicSums.size();
  this.numTerms = topicTermCounts.numCols();
  this.eta = eta;
  this.alpha = alpha;
  this.sampler = new Sampler(RandomUtils.getRandom());
  this.numThreads = numThreads;
  if (modelWeight != 1) {
    topicSums.assign(Functions.mult(modelWeight));
    for (int x = 0; x < numTopics; x++) {
      topicTermCounts.viewRow(x).assign(Functions.mult(modelWeight));
    }
  }
  initializeThreadPool();
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
public void trainDocTopicModel(Vector original, Vector topics, Matrix docTopicModel) {
  // first calculate p(topic|term,document) for all terms in original, and all topics,
  // using p(term|topic) and p(topic|doc)
  pTopicGivenTerm(original, topics, docTopicModel);
  normalizeByTopic(docTopicModel);
  // now multiply, term-by-term, by the document, to get the weighted distribution of
  // term-topic pairs from this document.
  Iterator<Vector.Element> it = original.iterateNonZero();
  while (it.hasNext()) {
    Vector.Element e = it.next();
    for (int x = 0; x < numTopics; x++) {
      Vector docTopicModelRow = docTopicModel.viewRow(x);
      docTopicModelRow.setQuick(e.index(), docTopicModelRow.getQuick(e.index()) * e.get());
    }
  }
  // now recalculate p(topic|doc) by summing contributions from all of pTopicGivenTerm
  topics.assign(0.0);
  for (int x = 0; x < numTopics; x++) {
    topics.set(x, docTopicModel.viewRow(x).norm(1));
  }
  // now renormalize so that sum_x(p(x|doc)) = 1
  topics.assign(Functions.mult(1/topics.norm(1)));
}
 

import org.apache.mahout.math.Matrix; //导入依赖的package包/类
private void normalizeByTopic(Matrix perTopicSparseDistributions) {
  Iterator<Vector.Element> it = perTopicSparseDistributions.viewRow(0).iterateNonZero();
  // then make sure that each of these is properly normalized by topic: sum_x(p(x|t,d)) = 1
  while (it.hasNext()) {
    Vector.Element e = it.next();
    int a = e.index();
    double sum = 0;
    for (int x = 0; x < numTopics; x++) {
      sum += perTopicSparseDistributions.viewRow(x).get(a);
    }
    for (int x = 0; x < numTopics; x++) {
      perTopicSparseDistributions.viewRow(x).set(a,
          perTopicSparseDistributions.viewRow(x).get(a) / sum);
    }
  }
}