KllDirectDoublesSketchIteratorTest.java

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *
 *   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.datasketches.kll;

import org.apache.datasketches.memory.DefaultMemoryRequestServer;
import org.apache.datasketches.memory.WritableMemory;
import org.apache.datasketches.quantilescommon.QuantilesDoublesSketchIterator;
import org.testng.Assert;
import org.testng.annotations.Test;

public class KllDirectDoublesSketchIteratorTest {
  private static final DefaultMemoryRequestServer memReqSvr = new DefaultMemoryRequestServer();

  @Test
  public void emptySketch() {
    final KllDoublesSketch sketch = getDDSketch(200, 0);
    QuantilesDoublesSketchIterator it = sketch.iterator();
    Assert.assertFalse(it.next());
  }

  @Test
  public void oneItemSketch() {
    final KllDoublesSketch sketch = getDDSketch(200, 0);
    sketch.update(0);
    QuantilesDoublesSketchIterator it = sketch.iterator();
    Assert.assertTrue(it.next());
    Assert.assertEquals(it.getQuantile(), 0);
    Assert.assertEquals(it.getWeight(), 1);
    Assert.assertFalse(it.next());
  }

  @Test
  public void bigSketches() {
    for (int n = 1000; n < 100000; n += 2000) {
      final KllDoublesSketch sketch = getDDSketch(200, 0);
      for (int i = 0; i < n; i++) {
        sketch.update(i);
      }
      QuantilesDoublesSketchIterator it = sketch.iterator();
      int count = 0;
      int weight = 0;
      while (it.next()) {
        count++;
        weight += (int)it.getWeight();
      }
      Assert.assertEquals(count, sketch.getNumRetained());
      Assert.assertEquals(weight, n);
    }
  }

  private static KllDoublesSketch getDDSketch(final int k, final int n) {
    KllDoublesSketch sk = KllDoublesSketch.newHeapInstance(k);
    for (int i = 1; i <= n; i++) { sk.update(i); }
    byte[] byteArr = KllHelper.toByteArray(sk, true);
    WritableMemory wmem = WritableMemory.writableWrap(byteArr);

    KllDoublesSketch ddsk = KllDoublesSketch.writableWrap(wmem, memReqSvr);
    return ddsk;
  }

}