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Diffstat (limited to 'guava-tests/benchmark/com/google/common/math/BigIntegerMathBenchmark.java')
-rw-r--r-- | guava-tests/benchmark/com/google/common/math/BigIntegerMathBenchmark.java | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/guava-tests/benchmark/com/google/common/math/BigIntegerMathBenchmark.java b/guava-tests/benchmark/com/google/common/math/BigIntegerMathBenchmark.java deleted file mode 100644 index 71095e5..0000000 --- a/guava-tests/benchmark/com/google/common/math/BigIntegerMathBenchmark.java +++ /dev/null @@ -1,119 +0,0 @@ -/* - * Copyright (C) 2011 The Guava Authors - * - * 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.google.common.math; - -import static com.google.common.math.MathBenchmarking.ARRAY_MASK; -import static com.google.common.math.MathBenchmarking.ARRAY_SIZE; -import static com.google.common.math.MathBenchmarking.RANDOM_SOURCE; -import static java.math.RoundingMode.CEILING; - -import com.google.caliper.Param; -import com.google.caliper.Runner; -import com.google.caliper.SimpleBenchmark; -import com.google.common.math.BigIntegerMath; -import com.google.common.math.IntMath; -import com.google.common.math.LongMath; - -import java.math.BigInteger; - -/** - * Benchmarks for the non-rounding methods of {@code BigIntegerMath}. - * - * @author Louis Wasserman - */ -public class BigIntegerMathBenchmark extends SimpleBenchmark { - private static final int[] factorials = new int[ARRAY_SIZE]; - private static final int[] slowFactorials = new int[ARRAY_SIZE]; - private static final int[] binomials = new int[ARRAY_SIZE]; - - @Param({"50", "1000", "10000"}) - int factorialBound; - - @Override - protected void setUp() { - for (int i = 0; i < ARRAY_SIZE; i++) { - factorials[i] = RANDOM_SOURCE.nextInt(factorialBound); - slowFactorials[i] = RANDOM_SOURCE.nextInt(factorialBound); - binomials[i] = RANDOM_SOURCE.nextInt(factorials[i] + 1); - } - } - - /** - * Previous version of BigIntegerMath.factorial, kept for timing purposes. - */ - private static BigInteger slowFactorial(int n) { - if (n <= 20) { - return BigInteger.valueOf(LongMath.factorial(n)); - } else { - int k = 20; - return BigInteger.valueOf(LongMath.factorial(k)).multiply(slowFactorial(k, n)); - } - } - - /** - * Returns the product of {@code n1} exclusive through {@code n2} inclusive. - */ - private static BigInteger slowFactorial(int n1, int n2) { - assert n1 <= n2; - if (IntMath.log2(n2, CEILING) * (n2 - n1) < Long.SIZE - 1) { - // the result will definitely fit into a long - long result = 1; - for (int i = n1 + 1; i <= n2; i++) { - result *= i; - } - return BigInteger.valueOf(result); - } - - /* - * We want each multiplication to have both sides with approximately the same number of digits. - * Currently, we just divide the range in half. - */ - int mid = (n1 + n2) >>> 1; - return slowFactorial(n1, mid).multiply(slowFactorial(mid, n2)); - } - - public int timeSlowFactorial(int reps) { - int tmp = 0; - for (int i = 0; i < reps; i++) { - int j = i & ARRAY_MASK; - tmp += slowFactorial(slowFactorials[j]).intValue(); - } - return tmp; - } - - public int timeFactorial(int reps) { - int tmp = 0; - for (int i = 0; i < reps; i++) { - int j = i & ARRAY_MASK; - tmp += BigIntegerMath.factorial(factorials[j]).intValue(); - } - return tmp; - } - - public int timeBinomial(int reps) { - int tmp = 0; - for (int i = 0; i < reps; i++) { - int j = i & 0xffff; - tmp += BigIntegerMath.binomial(factorials[j], binomials[j]).intValue(); - } - return tmp; - } - - public static void main(String[] args) { - Runner.main(BigIntegerMathBenchmark.class, args); - } -} |