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Fibonacci numbers (#376)

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* Fibonacci: Initial commit. Working.

* Fibonacci: Address Nick's comments. Added unchecked factorial.

* Fibonacci: Improved overflow testing

* Fibonacci: Added unit tests

* Fibonacci: Performance report

* Fibonacci: Nick's comments - Complexity

* Fibonacci: Add UT to Jamfile

* Make Fibonacci and UT C++03 friendly.

Add UT to Jamfile.

* Fibonacci: Remove GMP dependency

* 1. Added fibonacci generator with unit tests
2. Added example of reciprocal fibonacci constant

* [CI SKIP] Fibonacci: First cut at documentation

* Fibonacci: Finishing up changes [CI SKIP]

* Fibonacci: Removing unnecessary html files

* fibonacci: rename to unchecked_fibonacci

* fibonacci: remove documentation

Co-authored-by: Created by Ansible <madhur@dev-sng-build1.kdev>
This commit is contained in:
Madhur Chauhan
2021-03-16 18:41:10 +05:30
committed by GitHub
parent ef2fe8c586
commit 68d6a75f7c
5 changed files with 298 additions and 0 deletions
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reporting/performance/test_fibonacci.cpp Normal file
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// Copyright Madhur Chauhan 2020.
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <benchmark/benchmark.h>
#include <boost/math/special_functions/fibonacci.hpp>
#include <boost/multiprecision/gmp.hpp>
#include <utility>
using T = boost::multiprecision::mpz_int;
auto fib_rec(unsigned long long n) -> std::pair<T, T> {
if (n == 0) return {0, 1};
auto p = fib_rec(n >> 1);
T c = p.first * (2 * p.second - p.first);
T d = p.first * p.first + p.second * p.second;
return (n & 1) ? std::make_pair(d, c + d) : std::make_pair(c, d);
}
static void recursive_slow(benchmark::State &state) {
for (auto _ : state)
benchmark::DoNotOptimize(fib_rec(state.range(0)).first);
state.SetComplexityN(state.range(0));
}
constexpr int bm_start = 1 << 3, bm_end = 1 << 22;
BENCHMARK(recursive_slow)->Range(bm_start, bm_end)->Complexity();
static void iterative_fast(benchmark::State &state) {
for (auto _ : state)
benchmark::DoNotOptimize(boost::math::fibonacci<T>(state.range(0)));
state.SetComplexityN(state.range(0));
}
BENCHMARK(iterative_fast)->Range(bm_start, bm_end)->Complexity();
BENCHMARK_MAIN();
/*
Expected output:
CPU Caches:
L1 Data 32K (x4)
L1 Instruction 32K (x4)
L2 Unified 256K (x4)
L3 Unified 8192K (x4)
Load Average: 0.96, 0.80, 0.74
-----------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------
recursive_slow/8 3669 ns 3594 ns 190414
recursive_slow/64 6213 ns 6199 ns 116423
recursive_slow/512 8999 ns 8990 ns 78773
recursive_slow/4096 14529 ns 13984 ns 51206
recursive_slow/32768 74183 ns 73039 ns 8539
recursive_slow/262144 1297806 ns 1291304 ns 569
recursive_slow/2097152 23166565 ns 22751898 ns 30
recursive_slow/4194304 47038831 ns 46546938 ns 16
recursive_slow_BigO 0.51 NlgN 0.51 NlgN
recursive_slow_RMS 5 % 5 %
iterative_fast/8 1413 ns 1399 ns 493692
iterative_fast/64 2408 ns 2394 ns 298417
iterative_fast/512 4181 ns 4132 ns 170957
iterative_fast/4096 7627 ns 7558 ns 93554
iterative_fast/32768 65080 ns 64791 ns 11289
iterative_fast/262144 1207873 ns 1200725 ns 557
iterative_fast/2097152 19627331 ns 19510132 ns 36
iterative_fast/4194304 42351871 ns 42240620 ns 17
iterative_fast_BigO 0.46 NlgN 0.45 NlgN
iterative_fast_RMS 5 % 5 %
*/