content: /*
   * Copyright (C) 2011 Clearspring Technologies, Inc. 
   *
   * Licensed 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 com.clearspring.analytics.stream;
  
  import java.util.List;
  import java.util.Random;
  
  import org.junit.Before;
  import org.junit.Test;
  
  import cern.jet.random.Distributions;
  import cern.jet.random.engine.RandomEngine;
  import static org.junit.Assert.assertTrue;
  
  
  public class TestStochasticTopper {
  
      private static final int NUM_ITERATIONS = 100000;
      private static final int NUM_ELEMENTS = 10;
      private StochasticTopper<Integer> vs;
      private Random random;
  
      @Before
      public void setUp() {
          vs = new StochasticTopper<Integer>(200);
          random = new Random(340340990L);
      }
  
  
      @Test
      public void testGaussianDistribution() {
          for (int i = 0; i < NUM_ITERATIONS; i++) {
              vs.offer(new Integer((int) Math.round((random.nextGaussian() * NUM_ELEMENTS))));
          }
  
          List<Integer> top = vs.peek(5);
          System.out.println("Gaussian:");
          for (Integer e : top) {
              System.out.println(e);
          }
  
          int tippyTop = top.get(0);
          assertTrue(tippyTop > -15 && tippyTop < 15);
      }
  
      @Test
      public void testZipfianDistribution() {
          RandomEngine re = RandomEngine.makeDefault();
  
          for (int i = 0; i < NUM_ITERATIONS; i++) {
              int z = Distributions.nextZipfInt(1.2D, re);
              vs.offer(z);
          }
  
          List<Integer> top = vs.peek(5);
          System.out.println("Zipfian:");
          for (Integer e : top) {
              System.out.println(e);
          }
  
          int tippyTop = top.get(0);
          assertTrue(tippyTop < 3);
      }
  
      @Test
      public void testGeometricDistribution() {
          RandomEngine re = RandomEngine.makeDefault();
  
          for (int i = 0; i < NUM_ITERATIONS; i++) {
              int z = Distributions.nextGeometric(0.25, re);
              vs.offer(z);
          }
  
          List<Integer> top = vs.peek(5);
          System.out.println("Geometric:");
          for (Integer e : top) {
              System.out.println(e);
          }
  
          int tippyTop = top.get(0);
          assertTrue(tippyTop < 3);
      }
  
      @Test
      public void testRandomEngine() {
          int[] maxcounts = new int[10];
          int[] counts = new int[20];
  
          RandomEngine re = RandomEngine.makeDefault();
  
          for (int i = 0; i < NUM_ITERATIONS; i++) {
  //            int z = Distributions.nextZipfInt(1.2D, re);
              int z = Distributions.nextGeometric(0.25, re);
              if (z > Integer.MAX_VALUE - 9) {
                  maxcounts[Integer.MAX_VALUE - z]++;
              }
              if (z < 20) {
                  counts[z]++;
              }
          }
  
          for (int i = 0; i < 20; i++) {
              System.out.println(i + ": " + counts[i]);
          }
  
          for (int i = 9; i >= 0; i--) {
              System.out.println((Integer.MAX_VALUE - i) + ": " + maxcounts[i]);
          }
  
      }
  }
  