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      1 /*
      2  * Copyright (C) 2010 The Guava Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.common.collect;
     18 
     19 import static com.google.common.collect.DiscreteDomain.integers;
     20 
     21 import com.google.caliper.BeforeExperiment;
     22 import com.google.caliper.Benchmark;
     23 import com.google.caliper.Param;
     24 
     25 import java.util.Set;
     26 
     27 /**
     28  * Very simple powerSet iteration benchmark.
     29  *
     30  * @author Kevin Bourrillion
     31  */
     32 public class PowerSetBenchmark {
     33   @Param({"2", "4", "8", "16"}) int elements;
     34 
     35   Set<Set<Integer>> powerSet;
     36 
     37   @BeforeExperiment void setUp() {
     38     Set<Integer> set = ContiguousSet.create(Range.closed(1, elements), integers());
     39     powerSet = Sets.powerSet(set);
     40   }
     41 
     42   @Benchmark int iteration(int reps) {
     43     int sum = 0;
     44     for (int i = 0; i < reps; i++) {
     45       for (Set<Integer> subset : powerSet) {
     46         for (Integer value : subset) {
     47           sum += value;
     48         }
     49       }
     50     }
     51     return sum;
     52   }
     53 }
     54