indentation, finals, order of imports
diff --git a/src/main/java/com/yahoo/sketches/pig/tuple/ArrayOfDoublesSketchesToPValueEstimates.java b/src/main/java/com/yahoo/sketches/pig/tuple/ArrayOfDoublesSketchesToPValueEstimates.java
index 02fd11d..d2d59b2 100644
--- a/src/main/java/com/yahoo/sketches/pig/tuple/ArrayOfDoublesSketchesToPValueEstimates.java
+++ b/src/main/java/com/yahoo/sketches/pig/tuple/ArrayOfDoublesSketchesToPValueEstimates.java
@@ -5,90 +5,93 @@
package com.yahoo.sketches.pig.tuple;
-import com.yahoo.memory.Memory;
-import com.yahoo.sketches.tuple.ArrayOfDoublesSketch;
-import com.yahoo.sketches.tuple.ArrayOfDoublesSketches;
-import com.yahoo.sketches.tuple.ArrayOfDoublesSketchIterator;
-
import java.io.IOException;
-import org.apache.commons.math3.stat.inference.TTest;
import org.apache.commons.math3.stat.descriptive.SummaryStatistics;
+import org.apache.commons.math3.stat.inference.TTest;
import org.apache.pig.EvalFunc;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.Tuple;
+import com.yahoo.memory.Memory;
+import com.yahoo.sketches.tuple.ArrayOfDoublesSketch;
+import com.yahoo.sketches.tuple.ArrayOfDoublesSketchIterator;
+import com.yahoo.sketches.tuple.ArrayOfDoublesSketches;
+
/**
* Calculate p-values given two ArrayOfDoublesSketch. Each value in the sketch
* is treated as a separate metric measurement, and a p-value will be generated
* for each metric.
*/
public class ArrayOfDoublesSketchesToPValueEstimates extends EvalFunc<Tuple> {
- @Override
- public Tuple exec(final Tuple input) throws IOException {
- if ((input == null) || (input.size() != 2)) {
- return null;
- }
- // Get the two sketches
- final DataByteArray dbaA = (DataByteArray) input.get(0);
- final DataByteArray dbaB = (DataByteArray) input.get(1);
- final ArrayOfDoublesSketch sketchA = ArrayOfDoublesSketches.wrapSketch(Memory.wrap(dbaA.get()));
- final ArrayOfDoublesSketch sketchB = ArrayOfDoublesSketches.wrapSketch(Memory.wrap(dbaB.get()));
-
- // Check that the size of the arrays in the sketches are the same
- if (sketchA.getNumValues() != sketchB.getNumValues()) {
- throw new IllegalArgumentException("Both sketches must have the same number of values");
- }
-
- // Store the number of metrics
- int numMetrics = sketchA.getNumValues();
-
- // If the sketches contain fewer than 2 values, the p-value can't be calculated
- if (sketchA.getRetainedEntries() < 2 || sketchB.getRetainedEntries() < 2) {
- return null;
- }
-
- // Get the statistical summary from each sketch
- SummaryStatistics[] summaryA = sketchToSummaryStatistics(sketchA, numMetrics);
- SummaryStatistics[] summaryB = sketchToSummaryStatistics(sketchB, numMetrics);
-
- // Calculate the p-values
- double[] pValues = new double[numMetrics];
- TTest tTest = new TTest();
- for (int i = 0; i < numMetrics; i++) {
- // Pass the sampled values for each metric
- pValues[i] = tTest.tTest(summaryA[i], summaryB[i]);
- }
-
- return Util.doubleArrayToTuple(pValues);
+ @Override
+ public Tuple exec(final Tuple input) throws IOException {
+ if ((input == null) || (input.size() != 2)) {
+ return null;
}
- /**
- * Convert sketch to a summary statistic.
- *
- * @param sketch ArrayOfDoublesSketch to convert to a summary statistic.
- * @param numMetrics Number of metrics (values) in the ArrayOfDoublesSketch.
- * @return A summary statistic.
- */
- private SummaryStatistics[] sketchToSummaryStatistics(ArrayOfDoublesSketch sketch, int numMetrics) {
- // Store a summary statistic object for each metric
- SummaryStatistics[] summaryStatistics = new SummaryStatistics[numMetrics];
+ // Get the two sketches
+ final DataByteArray dbaA = (DataByteArray) input.get(0);
+ final DataByteArray dbaB = (DataByteArray) input.get(1);
+ final ArrayOfDoublesSketch sketchA = ArrayOfDoublesSketches.wrapSketch(Memory.wrap(dbaA.get()));
+ final ArrayOfDoublesSketch sketchB = ArrayOfDoublesSketches.wrapSketch(Memory.wrap(dbaB.get()));
- // Init the array
- for (int i = 0; i < numMetrics; i++) {
- summaryStatistics[i] = new SummaryStatistics();
- }
-
- // Add sketch values to the summary statistic object
- ArrayOfDoublesSketchIterator it = sketch.iterator();
- while (it.next()) {
- for (int i = 0; i < it.getValues().length; i++) {
- summaryStatistics[i].addValue(it.getValues()[i]);
- }
- }
-
- return summaryStatistics;
+ // Check that the size of the arrays in the sketches are the same
+ if (sketchA.getNumValues() != sketchB.getNumValues()) {
+ throw new IllegalArgumentException("Both sketches must have the same number of values");
}
+
+ // Store the number of metrics
+ final int numMetrics = sketchA.getNumValues();
+
+ // If the sketches contain fewer than 2 values, the p-value can't be calculated
+ if (sketchA.getRetainedEntries() < 2 || sketchB.getRetainedEntries() < 2) {
+ return null;
+ }
+
+ // Get the statistical summary from each sketch
+ final SummaryStatistics[] summaryA = sketchToSummaryStatistics(sketchA, numMetrics);
+ final SummaryStatistics[] summaryB = sketchToSummaryStatistics(sketchB, numMetrics);
+
+ // Calculate the p-values
+ final double[] pValues = new double[numMetrics];
+ final TTest tTest = new TTest();
+ for (int i = 0; i < numMetrics; i++) {
+ // Pass the sampled values for each metric
+ pValues[i] = tTest.tTest(summaryA[i], summaryB[i]);
+ }
+
+ return Util.doubleArrayToTuple(pValues);
+ }
+
+ /**
+ * Convert sketch to a summary statistic.
+ *
+ * @param sketch ArrayOfDoublesSketch to convert to a summary statistic.
+ * @param numMetrics Number of metrics (values) in the ArrayOfDoublesSketch.
+ * @return A summary statistic.
+ */
+ private static SummaryStatistics[] sketchToSummaryStatistics(final ArrayOfDoublesSketch sketch,
+ final int numMetrics) {
+ // Store a summary statistic object for each metric
+ final SummaryStatistics[] summaryStatistics = new SummaryStatistics[numMetrics];
+
+ // Init the array
+ for (int i = 0; i < numMetrics; i++) {
+ summaryStatistics[i] = new SummaryStatistics();
+ }
+
+ // Add sketch values to the summary statistic object
+ final ArrayOfDoublesSketchIterator it = sketch.iterator();
+ while (it.next()) {
+ for (int i = 0; i < it.getValues().length; i++) {
+ summaryStatistics[i].addValue(it.getValues()[i]);
+ }
+ }
+
+ return summaryStatistics;
+ }
+
}
