CPC Sketch Java Example

import java.io.FileInputStream;
import java.io.FileOutputStream;
import com.yahoo.memory.Memory;
import com.yahoo.sketches.cpc.CpcSketch;
import com.yahoo.sketches.cpc.CpcUnion;

//simplified file operations and no error handling for clarity
public class CpcExample {

  public static void main(String[] args) throws Exception {
    final int lgK = 10;
    // this section generates two sketches with some overlap and serializes them into files
    {
      // 100000 distinct keys
      CpcSketch sketch1 = new CpcSketch(lgK);
      for (int key = 0; key < 100000; key++) sketch1.update(key);
      FileOutputStream out1 = new FileOutputStream("CpcSketch1.bin");
      out1.write(sketch1.toByteArray());
      out1.close();

      // 100000 distinct keys
      CpcSketch sketch2 = new CpcSketch(lgK);
      for (int key = 50000; key < 150000; key++) sketch2.update(key);
      FileOutputStream out2 = new FileOutputStream("CpcSketch2.bin");
      out2.write(sketch2.toByteArray());
      out2.close();
    }

    // this section deserializes the sketches, produces a union and prints the result
    {
      FileInputStream in1 = new FileInputStream("CpcSketch1.bin");
      byte[] bytes1 = new byte[in1.available()];
      in1.read(bytes1);
      in1.close();
      CpcSketch sketch1 = CpcSketch.heapify(Memory.wrap(bytes1));

      FileInputStream in2 = new FileInputStream("CpcSketch2.bin");
      byte[] bytes2 = new byte[in2.available()];
      in2.read(bytes2);
      in2.close();
      CpcSketch sketch2 = CpcSketch.heapify(Memory.wrap(bytes2));

      CpcUnion union = new CpcUnion(lgK);
      union.update(sketch1);
      union.update(sketch2);
      CpcSketch result = union.getResult();

      // debug summary of the union result sketch
      System.out.println(result.toString());

      System.out.println("Distinct count estimate: " + result.getEstimate());
      System.out.println("Distinct count lower bound 95% confidence: " + result.getLowerBound(2));
      System.out.println("Distinct count upper bound 95% confidence: " + result.getUpperBound(2));
    }
  }

}

Output:
### CPD SKETCH - PREAMBLE:
  Flavor         : SLIDING
  LgK            : 10
  Merge Flag     : true
  Error Const    : 0.6931471805599453
  RSE            : 0.02166084939249829
  Seed Hash      : 93cc | 37836
  Num Coupons    : 7706
  Num Pairs (SV) : 27
  First Inter Col: 4
  Valid Window   : true
  Valid PairTable: true
  Window Offset  : 5
  KxP            : 1024.0
  HIP Accum      : 0.0
### END CPC SKETCH
Distinct count estimate: 149796.50599220005
Distinct count lower bound 95% confidence: 143416.2744812169
Distinct count upper bound 95% confidence: 156397.0