Examples of net.myrrix.online.factorizer.als.AlternatingLeastSquares

net.myrrix.online.factorizer.als.AlternatingLeastSquares

research.att.com/~yifanhu/PUB/cf.pdf">"Collaborative Filtering for Implicit Feedback Datasets" by Yifan Hu, Yehuda Koren, and Chris Volinsky.

This implementation varies in some small details; it does not use the same mechanism for explaining ratings for example and seeds the initial Y differently.

Note that in this implementation, matrices are sparse and are implemented with a {@link FastByIDMap} of{@link FastByIDFloatMap} so as to be able to use {@code long} keys. In many cases, a tall, skinny matrix isneeded (sparse rows, dense columns). This is represented with {@link FastByIDMap} of {@code float[]}.

@author Sean Owen @since 1.0

          System.getProperty("model.als.iterations.convergenceThreshold",
                             Double.toString(AlternatingLeastSquares.DEFAULT_CONVERGENCE_THRESHOLD));
      String maxIterationsString = 
          System.getProperty("model.iterations.max", 
                             Integer.toString(AlternatingLeastSquares.DEFAULT_MAX_ITERATIONS));    
      MatrixFactorizer als = new AlternatingLeastSquares(rbyRow, 
                                                         rbyColumn, 
                                                         features, 
                                                         Double.parseDouble(iterationsConvergenceString),
                                                         Integer.parseInt(maxIterationsString));
  
      if (currentGeneration != null) {
        FastByIDMap<float[]> previousY = currentGeneration.getY();
        if (previousY != null) {
          FastByIDMap<float[]> previousYClone;
          Lock yLock = currentGeneration.getYLock().readLock();
          yLock.lock();
          try {
            previousYClone = new FastByIDMap<float[]>(previousY.size());
            for (FastByIDMap.MapEntry<float[]> entry : previousY.entrySet()) {
              previousYClone.put(entry.getKey(), entry.getValue().clone());
            }
          } finally {
            yLock.unlock();
          }
          als.setPreviousY(previousYClone);
        }
      }
  
      try {
        als.call();
        log.info("Factorization complete");
      } catch (ExecutionException ee) {
        throw new IOException(ee.getCause());
      } catch (InterruptedException ignored) {
        log.warn("ALS computation was interrupted");

Examples of net.myrrix.online.factorizer.als.AlternatingLeastSquares

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