ceph/src/boost/libs/multiprecision/performance/rational_bernoulli_bench.cpp

   1 //  Copyright 2020 John Maddock. Distributed under the Boost
   2 //  Software License, Version 1.0. (See accompanying file
   3 //  LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
   4
   5 #include <iostream>
   6 #include <benchmark/benchmark.h>
   7 #include <boost/multiprecision/cpp_int.hpp>
   8 #include <boost/multiprecision/gmp.hpp>
   9
  10 #include <gmpxx.h>
  11
  12 template <class Integer>
  13 inline Integer factorial(unsigned n)
  14 {
  15    Integer result = 1;
  16    for (unsigned k = 1; k <= n; ++k)
  17       result *= k;
  18    return result;
  19 }
  20
  21 template <class Rational, class Integer = typename Rational::value_type>
  22 inline Rational binomial(unsigned n, unsigned k)
  23 {
  24    return Rational(factorial<Integer>(n), factorial<Integer>(k) * factorial<Integer>(n - k));
  25 }
  26
  27 inline mpz_class pow(mpz_class i, unsigned p)
  28 {
  29    mpz_class result;
  30    mpz_pow_ui(result.get_mpz_t(), i.get_mpz_t(), p);
  31    return result;
  32 }
  33
  34 template <class Rational, class Integer = typename Rational::value_type>
  35 Rational Bernoulli(unsigned m)
  36 {
  37    Rational result = 0;
  38
  39    for (unsigned k = 0; k <= m; ++k)
  40    {
  41       Rational inner = 0;
  42       for (unsigned v = 0; v <= k; ++v)
  43       {
  44          Rational term = binomial<Rational, Integer>(k, v) * Rational(pow(Integer(v), m), k + 1);
  45          if (v & 1)
  46             term = -term;
  47          inner += term;
  48       }
  49       result += inner;
  50    }
  51    return result;
  52 }
  53
  54 template <class Rational, class Integer = typename Rational::value_type>
  55 static void BM_bernoulli(benchmark::State& state)
  56 {
  57    int m = state.range(0);
  58    for (auto _ : state)
  59    {
  60       benchmark::DoNotOptimize(Bernoulli<Rational, Integer>(m));
  61    }
  62 }
  63
  64
  65 BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::cpp_rational)->DenseRange(50, 200, 4);
  66 BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::mpq_rational)->DenseRange(50, 200, 4);
  67 BENCHMARK_TEMPLATE(BM_bernoulli, boost::multiprecision::number<boost::multiprecision::rational_adaptor<boost::multiprecision::gmp_int> >)->DenseRange(50, 200, 4);
  68 BENCHMARK_TEMPLATE(BM_bernoulli, mpq_class, mpz_class)->DenseRange(50, 200, 4);
  69
  70 BENCHMARK_MAIN();