Mean and Variance

gistfile1.java

import org.apache.spark.mllib.stat.MultivariateStatisticalSummary;
import org.apache.spark.mllib.stat.Statistics;

private MultivariateStatisticalSummary summary;

public ExtractFeature(JavaRDD<Vector> data) {
  this.summary = Statistics.colStats(data.rdd());
}

// return (mean_acc_x, mean_acc_y, mean_acc_z)
public double[] computeAvgAcc() {
  return this.summary.mean().toArray();
}
// return (var_acc_x, var_acc_y, var_acc_z)
public double[] computeVariance() {
  return this.summary.variance().toArray();
}