src/test/java/org/apache/datasketches/quantiles/DirectUpdateDoublesSketchTest.java - datasketches-java - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */

 package org.apache.datasketches.quantiles;

 import static java.lang.foreign.ValueLayout.JAVA_DOUBLE_UNALIGNED;
 import static org.apache.datasketches.common.Util.LS;
 import static org.apache.datasketches.common.Util.ceilingPowerOf2;
 import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.EXCLUSIVE;
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;

 import java.lang.foreign.MemorySegment;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;

 import org.apache.datasketches.common.SketchesArgumentException;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;

 public class DirectUpdateDoublesSketchTest {


   @BeforeMethod
   public void setUp() {
     QuantilesDoublesSketch.rand.setSeed(32749); // make sketches deterministic for testing
   }

   @Test
   public void checkSmallMinMax () {
     final int k = 32;
     final int n = 8;
     final UpdatableQuantilesDoublesSketch qs1 = buildDQS(k, n);
     final UpdatableQuantilesDoublesSketch qs2 = buildDQS(k, n);
     final UpdatableQuantilesDoublesSketch qs3 = buildDQS(k, n);

     for (int i = n; i >= 1; i--) {
       qs1.update(i);
       qs2.update(10+i);
       qs3.update(i);
     }
     assertEquals(qs1.getQuantile (0.0, EXCLUSIVE), 1.0);
     assertEquals(qs1.getQuantile (0.5, EXCLUSIVE), 5.0);
     assertEquals(qs1.getQuantile (1.0, EXCLUSIVE), 8.0);

     assertEquals(qs2.getQuantile (0.0, EXCLUSIVE), 11.0);
     assertEquals(qs2.getQuantile (0.5, EXCLUSIVE), 15.0);
     assertEquals(qs2.getQuantile (1.0, EXCLUSIVE), 18.0);

     assertEquals(qs3.getQuantile (0.0, EXCLUSIVE), 1.0);
     assertEquals(qs3.getQuantile (0.5, EXCLUSIVE), 5.0);
     assertEquals(qs3.getQuantile (1.0, EXCLUSIVE), 8.0);

     final double[] queries = {0.0, 0.5, 1.0};

     final double[] resultsA = qs1.getQuantiles(queries, EXCLUSIVE);
     assertEquals(resultsA[0], 1.0);
     assertEquals(resultsA[1], 5.0);
     assertEquals(resultsA[2], 8.0);

     final QuantilesDoublesUnion union1 = QuantilesDoublesUnion.heapify(qs1);
     union1.union(qs2);
     final QuantilesDoublesSketch result1 = union1.getResult();

     final QuantilesDoublesUnion union2 = QuantilesDoublesUnion.heapify(qs2);
     union2.union(qs3);
     final QuantilesDoublesSketch result2 = union2.getResult();

     final double[] resultsB = result1.getQuantiles(queries, EXCLUSIVE);
     printResults(resultsB);
     assertEquals(resultsB[0], 1.0);
     assertEquals(resultsB[1], 11.0);
     assertEquals(resultsB[2], 18.0);

     final double[] resultsC = result2.getQuantiles(queries, EXCLUSIVE);
     assertEquals(resultsC[0], 1.0);
     assertEquals(resultsC[1], 11.0);
     assertEquals(resultsC[2], 18.0);
   }

   static void printResults(final double[] results) {
     println(results[0] + ", " + results[1] + ", " + results[2]);
   }

   @Test
   public void wrapEmptyUpdateSketch() {
     final UpdatableQuantilesDoublesSketch s1 = QuantilesDoublesSketch.builder().build();
     final MemorySegment seg = MemorySegment.ofBuffer(ByteBuffer.wrap(s1.toByteArray()).order(ByteOrder.nativeOrder()));
     final UpdatableQuantilesDoublesSketch s2 = DirectUpdateDoublesSketch.wrapInstance(seg, null);
     assertTrue(s2.isEmpty());

     assertEquals(s2.getN(), 0);
     assertTrue(Double.isNaN(s2.isEmpty() ? Double.NaN : s2.getMinItem()));
     assertTrue(Double.isNaN(s2.isEmpty() ? Double.NaN : s2.getMaxItem()));

     s2.reset(); // empty: a no-op
     assertEquals(s2.getN(), 0);
   }

   @Test
   public void checkPutCombinedBuffer() {
     final int k = PreambleUtil.DEFAULT_K;
     final int cap = 32 + ((2 * k) << 3);
     MemorySegment seg = MemorySegment.ofArray(new byte[cap]);
     final UpdatableQuantilesDoublesSketch qs = QuantilesDoublesSketch.builder().setK(k).build(seg);
     seg = qs.getMemorySegment();
     assertEquals(seg.byteSize(), cap);
     assertTrue(qs.isEmpty());

     final int n = 16;
     final double[] data = new double[n];
     for (int i = 0; i < n; ++i) {
       data[i] = i + 1;
     }
     qs.putBaseBufferCount(n);
     qs.putN(n);
     qs.putCombinedBuffer(data);

     final double[] combBuf = qs.getCombinedBuffer();
     assertEquals(combBuf, data);

     // shouldn't have changed min/max values
     assertTrue(Double.isNaN(qs.getMinItem()));
     assertTrue(Double.isNaN(qs.getMaxItem()));
   }

   @Test
   public void checkMisc() {
     final int k = PreambleUtil.DEFAULT_K;
     final int n = 48;
     final int cap = 32 + ((2 * k) << 3);
     MemorySegment seg = MemorySegment.ofArray(new byte[cap]);
     UpdatableQuantilesDoublesSketch qs = QuantilesDoublesSketch.builder().setK(k).build(seg);
     seg = qs.getMemorySegment();
     assertEquals(seg.byteSize(), cap);
     double[] combBuf = qs.getCombinedBuffer();
     assertEquals(combBuf.length, 2 * k);
     qs = buildAndLoadDQS(k, n);
     qs.update(Double.NaN);
     final int n2 = (int)qs.getN();
     assertEquals(n2, n);
     combBuf = qs.getCombinedBuffer();
     assertEquals(combBuf.length, ceilingPowerOf2(n)); // since n < k
     println(qs.toString(true, true));
     qs.reset();
     assertEquals(qs.getN(), 0);
     qs.putBaseBufferCount(0);
   }

   @SuppressWarnings("unused")
   @Test
   public void variousExceptions() {
     final MemorySegment seg = MemorySegment.ofArray(new byte[8]);
     try {
       final int flags = PreambleUtil.COMPACT_FLAG_MASK;
       DirectUpdateDoublesSketch.checkCompact(2, 0);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
     try {
       final int flags = PreambleUtil.COMPACT_FLAG_MASK;
       DirectUpdateDoublesSketch.checkCompact(3, flags);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
     try {
       DirectUpdateDoublesSketch.checkPreLongs(3);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
     try {
       DirectUpdateDoublesSketch.checkPreLongs(0);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
     try {
       DirectUpdateDoublesSketch.checkDirectFlags(PreambleUtil.COMPACT_FLAG_MASK);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
     try {
       DirectUpdateDoublesSketch.checkEmptyAndN(true, 1);
       fail();
     } catch (final SketchesArgumentException e) {} //OK
   }

   @Test
   public void checkCheckDirectSegCapacity() {
     final int k = 128;
     DirectUpdateDoublesSketch.checkDirectSegCapacity(k, (2 * k) - 1, (4 + (2 * k)) * 8);
     DirectUpdateDoublesSketch.checkDirectSegCapacity(k, (2 * k) + 1, (4 + (3 * k)) * 8);
     DirectUpdateDoublesSketch.checkDirectSegCapacity(k, 0, 8);

     try {
       DirectUpdateDoublesSketch.checkDirectSegCapacity(k, 10000, 64);
       fail();
     } catch (final SketchesArgumentException e) {
       // expected
     }
   }

   @Test
   public void serializeDeserialize() {
     final int sizeBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(128, 2000);
     final MemorySegment seg = MemorySegment.ofArray(new byte[sizeBytes]);
     final UpdatableQuantilesDoublesSketch sketch1 = QuantilesDoublesSketch.builder().build(seg);
     for (int i = 0; i < 1000; i++) {
       sketch1.update(i);
     }

     final UpdatableQuantilesDoublesSketch sketch2 = UpdatableQuantilesDoublesSketch.wrap(seg, null);
     for (int i = 0; i < 1000; i++) {
       sketch2.update(i + 1000);
     }
     assertEquals(sketch2.getMinItem(), 0.0);
     assertEquals(sketch2.getMaxItem(), 1999.0);
     assertEquals(sketch2.getQuantile(0.5), 1000.0, 10.0);

     final byte[] arr2 = sketch2.toByteArray(false);
     assertEquals(arr2.length, sketch2.getSerializedSizeBytes());
     final QuantilesDoublesSketch sketch3 = QuantilesDoublesSketch.writableWrap(MemorySegment.ofArray(arr2), null);
     assertEquals(sketch3.getMinItem(), 0.0);
     assertEquals(sketch3.getMaxItem(), 1999.0);
     assertEquals(sketch3.getQuantile(0.5), 1000.0, 10.0);
   }

   @Test
   public void mergeTest() {
     final QuantilesDoublesSketch dqs1 = buildAndLoadDQS(128, 256);
     final QuantilesDoublesSketch dqs2 = buildAndLoadDQS(128, 256, 256);
     final QuantilesDoublesUnion union = QuantilesDoublesUnion.builder().setMaxK(128).build();
     union.union(dqs1);
     union.union(dqs2);
     final QuantilesDoublesSketch result = union.getResult();
     final double median = result.getQuantile(0.5);
     println("Median: " + median);
     assertEquals(median, 258.0, .05 * 258);
   }

   @Test
   public void checkSimplePropagateCarryDirect() {
     final int k = 16;
     final int n = k * 2;

     final int segBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
     final MemorySegment seg = MemorySegment.ofArray(new byte[segBytes]);
     final QuantilesDoublesSketchBuilder bldr = QuantilesDoublesSketch.builder();
     final UpdatableQuantilesDoublesSketch ds = bldr.setK(k).build(seg);
     for (int i = 1; i <= n; i++) { // 1 ... n
       ds.update(i);
     }
     double last = 0.0;
     for (int i = 0; i < k; i++) { //check the level 0
       final double d = seg.get(JAVA_DOUBLE_UNALIGNED, (4 + (2 * k) + i) << 3);
       assertTrue(d > 0);
       assertTrue(d > last);
       last = d;
     }
     //println(ds.toString(true, true));
   }

   @Test
   public void getRankAndGetCdfConsistency() {
     final int k = 128;
     final int n = 1_000_000;
     final int segBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
     final MemorySegment seg = MemorySegment.ofArray(new byte[segBytes]);
     final UpdatableQuantilesDoublesSketch sketch = QuantilesDoublesSketch.builder().build(seg);
     final double[] values = new double[n];
     for (int i = 0; i < n; i++) {
       sketch.update(i);
       values[i] = i;
     }
     final double[] ranks = sketch.getCDF(values);
     for (int i = 0; i < n; i++) {
       assertEquals(ranks[i], sketch.getRank(values[i]));
     }
   }

   static UpdatableQuantilesDoublesSketch buildAndLoadDQS(final int k, final int n) {
     return buildAndLoadDQS(k, n, 0);
   }

   static UpdatableQuantilesDoublesSketch buildAndLoadDQS(final int k, final long n, final int startV) {
     final UpdatableQuantilesDoublesSketch qs = buildDQS(k, n);
     for (long i = 1; i <= n; i++) {
       qs.update(startV + i);
     }
     return qs;
   }

   static UpdatableQuantilesDoublesSketch buildDQS(final int k, final long n) {
     int cap = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
     if (cap < (2 * k)) { cap = 2 * k; }
     final QuantilesDoublesSketchBuilder bldr = new QuantilesDoublesSketchBuilder();
     bldr.setK(k);
     return bldr.build(MemorySegment.ofArray(new byte[cap]));
   }

   @Test
   public void printlnTest() {
     println("PRINTING: " + this.getClass().getName());
   }

   /**
    * @param s value to print
    */
   static void println(final String s) {
     print(s+LS);
   }

   /**
    * @param s value to print
    */
   static void print(final String s) {
     //System.err.print(s); //disable here
   }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/

	package org.apache.datasketches.quantiles;

	import static java.lang.foreign.ValueLayout.JAVA_DOUBLE_UNALIGNED;
	import static org.apache.datasketches.common.Util.LS;
	import static org.apache.datasketches.common.Util.ceilingPowerOf2;
	import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.EXCLUSIVE;
	import static org.testng.Assert.assertEquals;
	import static org.testng.Assert.assertTrue;
	import static org.testng.Assert.fail;

	import java.lang.foreign.MemorySegment;
	import java.nio.ByteBuffer;
	import java.nio.ByteOrder;

	import org.apache.datasketches.common.SketchesArgumentException;
	import org.testng.annotations.BeforeMethod;
	import org.testng.annotations.Test;

	public class DirectUpdateDoublesSketchTest {


	@BeforeMethod
	public void setUp() {
	QuantilesDoublesSketch.rand.setSeed(32749); // make sketches deterministic for testing
	}

	@Test
	public void checkSmallMinMax () {
	final int k = 32;
	final int n = 8;
	final UpdatableQuantilesDoublesSketch qs1 = buildDQS(k, n);
	final UpdatableQuantilesDoublesSketch qs2 = buildDQS(k, n);
	final UpdatableQuantilesDoublesSketch qs3 = buildDQS(k, n);

	for (int i = n; i >= 1; i--) {
	qs1.update(i);
	qs2.update(10+i);
	qs3.update(i);
	}
	assertEquals(qs1.getQuantile (0.0, EXCLUSIVE), 1.0);
	assertEquals(qs1.getQuantile (0.5, EXCLUSIVE), 5.0);
	assertEquals(qs1.getQuantile (1.0, EXCLUSIVE), 8.0);

	assertEquals(qs2.getQuantile (0.0, EXCLUSIVE), 11.0);
	assertEquals(qs2.getQuantile (0.5, EXCLUSIVE), 15.0);
	assertEquals(qs2.getQuantile (1.0, EXCLUSIVE), 18.0);

	assertEquals(qs3.getQuantile (0.0, EXCLUSIVE), 1.0);
	assertEquals(qs3.getQuantile (0.5, EXCLUSIVE), 5.0);
	assertEquals(qs3.getQuantile (1.0, EXCLUSIVE), 8.0);

	final double[] queries = {0.0, 0.5, 1.0};

	final double[] resultsA = qs1.getQuantiles(queries, EXCLUSIVE);
	assertEquals(resultsA[0], 1.0);
	assertEquals(resultsA[1], 5.0);
	assertEquals(resultsA[2], 8.0);

	final QuantilesDoublesUnion union1 = QuantilesDoublesUnion.heapify(qs1);
	union1.union(qs2);
	final QuantilesDoublesSketch result1 = union1.getResult();

	final QuantilesDoublesUnion union2 = QuantilesDoublesUnion.heapify(qs2);
	union2.union(qs3);
	final QuantilesDoublesSketch result2 = union2.getResult();

	final double[] resultsB = result1.getQuantiles(queries, EXCLUSIVE);
	printResults(resultsB);
	assertEquals(resultsB[0], 1.0);
	assertEquals(resultsB[1], 11.0);
	assertEquals(resultsB[2], 18.0);

	final double[] resultsC = result2.getQuantiles(queries, EXCLUSIVE);
	assertEquals(resultsC[0], 1.0);
	assertEquals(resultsC[1], 11.0);
	assertEquals(resultsC[2], 18.0);
	}

	static void printResults(final double[] results) {
	println(results[0] + ", " + results[1] + ", " + results[2]);
	}

	@Test
	public void wrapEmptyUpdateSketch() {
	final UpdatableQuantilesDoublesSketch s1 = QuantilesDoublesSketch.builder().build();
	final MemorySegment seg = MemorySegment.ofBuffer(ByteBuffer.wrap(s1.toByteArray()).order(ByteOrder.nativeOrder()));
	final UpdatableQuantilesDoublesSketch s2 = DirectUpdateDoublesSketch.wrapInstance(seg, null);
	assertTrue(s2.isEmpty());

	assertEquals(s2.getN(), 0);
	assertTrue(Double.isNaN(s2.isEmpty() ? Double.NaN : s2.getMinItem()));
	assertTrue(Double.isNaN(s2.isEmpty() ? Double.NaN : s2.getMaxItem()));

	s2.reset(); // empty: a no-op
	assertEquals(s2.getN(), 0);
	}

	@Test
	public void checkPutCombinedBuffer() {
	final int k = PreambleUtil.DEFAULT_K;
	final int cap = 32 + ((2 * k) << 3);
	MemorySegment seg = MemorySegment.ofArray(new byte[cap]);
	final UpdatableQuantilesDoublesSketch qs = QuantilesDoublesSketch.builder().setK(k).build(seg);
	seg = qs.getMemorySegment();
	assertEquals(seg.byteSize(), cap);
	assertTrue(qs.isEmpty());

	final int n = 16;
	final double[] data = new double[n];
	for (int i = 0; i < n; ++i) {
	data[i] = i + 1;
	}
	qs.putBaseBufferCount(n);
	qs.putN(n);
	qs.putCombinedBuffer(data);

	final double[] combBuf = qs.getCombinedBuffer();
	assertEquals(combBuf, data);

	// shouldn't have changed min/max values
	assertTrue(Double.isNaN(qs.getMinItem()));
	assertTrue(Double.isNaN(qs.getMaxItem()));
	}

	@Test
	public void checkMisc() {
	final int k = PreambleUtil.DEFAULT_K;
	final int n = 48;
	final int cap = 32 + ((2 * k) << 3);
	MemorySegment seg = MemorySegment.ofArray(new byte[cap]);
	UpdatableQuantilesDoublesSketch qs = QuantilesDoublesSketch.builder().setK(k).build(seg);
	seg = qs.getMemorySegment();
	assertEquals(seg.byteSize(), cap);
	double[] combBuf = qs.getCombinedBuffer();
	assertEquals(combBuf.length, 2 * k);
	qs = buildAndLoadDQS(k, n);
	qs.update(Double.NaN);
	final int n2 = (int)qs.getN();
	assertEquals(n2, n);
	combBuf = qs.getCombinedBuffer();
	assertEquals(combBuf.length, ceilingPowerOf2(n)); // since n < k
	println(qs.toString(true, true));
	qs.reset();
	assertEquals(qs.getN(), 0);
	qs.putBaseBufferCount(0);
	}

	@SuppressWarnings("unused")
	@Test
	public void variousExceptions() {
	final MemorySegment seg = MemorySegment.ofArray(new byte[8]);
	try {
	final int flags = PreambleUtil.COMPACT_FLAG_MASK;
	DirectUpdateDoublesSketch.checkCompact(2, 0);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	try {
	final int flags = PreambleUtil.COMPACT_FLAG_MASK;
	DirectUpdateDoublesSketch.checkCompact(3, flags);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	try {
	DirectUpdateDoublesSketch.checkPreLongs(3);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	try {
	DirectUpdateDoublesSketch.checkPreLongs(0);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	try {
	DirectUpdateDoublesSketch.checkDirectFlags(PreambleUtil.COMPACT_FLAG_MASK);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	try {
	DirectUpdateDoublesSketch.checkEmptyAndN(true, 1);
	fail();
	} catch (final SketchesArgumentException e) {} //OK
	}

	@Test
	public void checkCheckDirectSegCapacity() {
	final int k = 128;
	DirectUpdateDoublesSketch.checkDirectSegCapacity(k, (2 * k) - 1, (4 + (2 * k)) * 8);
	DirectUpdateDoublesSketch.checkDirectSegCapacity(k, (2 * k) + 1, (4 + (3 * k)) * 8);
	DirectUpdateDoublesSketch.checkDirectSegCapacity(k, 0, 8);

	try {
	DirectUpdateDoublesSketch.checkDirectSegCapacity(k, 10000, 64);
	fail();
	} catch (final SketchesArgumentException e) {
	// expected
	}
	}

	@Test
	public void serializeDeserialize() {
	final int sizeBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(128, 2000);
	final MemorySegment seg = MemorySegment.ofArray(new byte[sizeBytes]);
	final UpdatableQuantilesDoublesSketch sketch1 = QuantilesDoublesSketch.builder().build(seg);
	for (int i = 0; i < 1000; i++) {
	sketch1.update(i);
	}

	final UpdatableQuantilesDoublesSketch sketch2 = UpdatableQuantilesDoublesSketch.wrap(seg, null);
	for (int i = 0; i < 1000; i++) {
	sketch2.update(i + 1000);
	}
	assertEquals(sketch2.getMinItem(), 0.0);
	assertEquals(sketch2.getMaxItem(), 1999.0);
	assertEquals(sketch2.getQuantile(0.5), 1000.0, 10.0);

	final byte[] arr2 = sketch2.toByteArray(false);
	assertEquals(arr2.length, sketch2.getSerializedSizeBytes());
	final QuantilesDoublesSketch sketch3 = QuantilesDoublesSketch.writableWrap(MemorySegment.ofArray(arr2), null);
	assertEquals(sketch3.getMinItem(), 0.0);
	assertEquals(sketch3.getMaxItem(), 1999.0);
	assertEquals(sketch3.getQuantile(0.5), 1000.0, 10.0);
	}

	@Test
	public void mergeTest() {
	final QuantilesDoublesSketch dqs1 = buildAndLoadDQS(128, 256);
	final QuantilesDoublesSketch dqs2 = buildAndLoadDQS(128, 256, 256);
	final QuantilesDoublesUnion union = QuantilesDoublesUnion.builder().setMaxK(128).build();
	union.union(dqs1);
	union.union(dqs2);
	final QuantilesDoublesSketch result = union.getResult();
	final double median = result.getQuantile(0.5);
	println("Median: " + median);
	assertEquals(median, 258.0, .05 * 258);
	}

	@Test
	public void checkSimplePropagateCarryDirect() {
	final int k = 16;
	final int n = k * 2;

	final int segBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
	final MemorySegment seg = MemorySegment.ofArray(new byte[segBytes]);
	final QuantilesDoublesSketchBuilder bldr = QuantilesDoublesSketch.builder();
	final UpdatableQuantilesDoublesSketch ds = bldr.setK(k).build(seg);
	for (int i = 1; i <= n; i++) { // 1 ... n
	ds.update(i);
	}
	double last = 0.0;
	for (int i = 0; i < k; i++) { //check the level 0
	final double d = seg.get(JAVA_DOUBLE_UNALIGNED, (4 + (2 * k) + i) << 3);
	assertTrue(d > 0);
	assertTrue(d > last);
	last = d;
	}
	//println(ds.toString(true, true));
	}

	@Test
	public void getRankAndGetCdfConsistency() {
	final int k = 128;
	final int n = 1_000_000;
	final int segBytes = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
	final MemorySegment seg = MemorySegment.ofArray(new byte[segBytes]);
	final UpdatableQuantilesDoublesSketch sketch = QuantilesDoublesSketch.builder().build(seg);
	final double[] values = new double[n];
	for (int i = 0; i < n; i++) {
	sketch.update(i);
	values[i] = i;
	}
	final double[] ranks = sketch.getCDF(values);
	for (int i = 0; i < n; i++) {
	assertEquals(ranks[i], sketch.getRank(values[i]));
	}
	}

	static UpdatableQuantilesDoublesSketch buildAndLoadDQS(final int k, final int n) {
	return buildAndLoadDQS(k, n, 0);
	}

	static UpdatableQuantilesDoublesSketch buildAndLoadDQS(final int k, final long n, final int startV) {
	final UpdatableQuantilesDoublesSketch qs = buildDQS(k, n);
	for (long i = 1; i <= n; i++) {
	qs.update(startV + i);
	}
	return qs;
	}

	static UpdatableQuantilesDoublesSketch buildDQS(final int k, final long n) {
	int cap = QuantilesDoublesSketch.getUpdatableStorageBytes(k, n);
	if (cap < (2 * k)) { cap = 2 * k; }
	final QuantilesDoublesSketchBuilder bldr = new QuantilesDoublesSketchBuilder();
	bldr.setK(k);
	return bldr.build(MemorySegment.ofArray(new byte[cap]));
	}

	@Test
	public void printlnTest() {
	println("PRINTING: " + this.getClass().getName());
	}

	/**
	* @param s value to print
	*/
	static void println(final String s) {
	print(s+LS);
	}

	/**
	* @param s value to print
	*/
	static void print(final String s) {
	//System.err.print(s); //disable here
	}

	}