hll/test/CrossCountingTest.cpp

/*
 * 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.
 */

#include "hll.hpp"

#include <cppunit/TestFixture.h>
#include <cppunit/extensions/HelperMacros.h>
#include <ostream>
#include <cmath>
#include <string>

namespace datasketches {

class CrossCountingTest : public CppUnit::TestFixture {

  CPPUNIT_TEST_SUITE(CrossCountingTest);
  CPPUNIT_TEST(crossCountingChecks);
  CPPUNIT_TEST_SUITE_END();

  hll_sketch buildSketch(const int n, const int lgK, const target_hll_type tgtHllType) {
    hll_sketch sketch(lgK, tgtHllType);
    for (int i = 0; i < n; ++i) {
      sketch.update(i);
    }
    return sketch;
  }

  int computeChecksum(const hll_sketch& sketch) {
    pair_iterator_with_deleter<> itr = sketch.get_iterator();
    int checksum = 0;
    int key;
    while(itr->nextAll()) {
      checksum += itr->getPair();
      key = itr->getKey(); // dummy
    }
    CPPUNIT_ASSERT(key >= 0); // avoids "set but unused" warning
    return checksum;
  }

  void crossCountingCheck(const int lgK, const int n) {
    hll_sketch sk4 = buildSketch(n, lgK, HLL_4);
    int s4csum = computeChecksum(sk4);
    int csum;

    hll_sketch sk6 = buildSketch(n, lgK, HLL_6);
    csum = computeChecksum(sk6);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk8 = buildSketch(n, lgK, HLL_8);
    csum = computeChecksum(sk8);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);
  
    // Conversions
    hll_sketch sk4to6(sk4, HLL_6);
    csum = computeChecksum(sk4to6);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk4to8(sk4, HLL_8);
    csum = computeChecksum(sk4to8);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk6to4(sk6, HLL_4);
    csum = computeChecksum(sk6to4);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk6to8(sk6, HLL_8);
    csum = computeChecksum(sk6to8);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk8to4(sk8, HLL_4);
    csum = computeChecksum(sk8to4);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);

    hll_sketch sk8to6(sk8, HLL_6);
    csum = computeChecksum(sk8to6);
    CPPUNIT_ASSERT_EQUAL(csum, s4csum);
  }

  void crossCountingChecks() {
    crossCountingCheck(4, 100);
    crossCountingCheck(4, 10000);
    crossCountingCheck(12, 7);
    crossCountingCheck(12, 384);
    crossCountingCheck(12, 10000);
  }

};

CPPUNIT_TEST_SUITE_REGISTRATION(CrossCountingTest);

} /* namespace datasketches */