accumulators/example/main.cpp
Yuval Lifshitz ff9432f97b Allow accumulator persistency (#18)
* Add, and update, documentation build targets.

* adding serialization to stats

* serialize rolling stats
2019-05-10 15:39:28 -07:00

263 lines
9.3 KiB
C++

///////////////////////////////////////////////////////////////////////////////
// main.hpp
//
// Copyright 2005 Eric Niebler. Distributed under 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 <iostream>
#include <fstream> // needed for de/serialization example (4)
#include <algorithm>
#include <boost/ref.hpp>
#include <boost/bind.hpp>
#include <boost/array.hpp>
#include <boost/foreach.hpp>
#include <boost/accumulators/accumulators.hpp>
#include <boost/accumulators/statistics.hpp>
// needed for de/serialization example (4)
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
using namespace boost;
using namespace boost::accumulators;
// Helper that uses BOOST_FOREACH to display a range of doubles
template<typename Range>
void output_range(Range const &rng)
{
bool first = true;
BOOST_FOREACH(double d, rng)
{
if(!first) std::cout << ", ";
std::cout << d;
first = false;
}
std::cout << '\n';
}
///////////////////////////////////////////////////////////////////////////////
// example1
//
// Calculate some useful stats using accumulator_set<> and std::for_each()
//
void example1()
{
accumulator_set<
double
, stats<tag::min, tag::mean(immediate), tag::sum, tag::moment<2> >
> acc;
boost::array<double, 4> data = {0., 1., -1., 3.14159};
// std::for_each pushes each sample into the accumulator one at a
// time, and returns a copy of the accumulator.
acc = std::for_each(data.begin(), data.end(), acc);
// The following would be equivalent, and could be more efficient
// because it doesn't pass and return the entire accumulator set
// by value.
//std::for_each(data.begin(), data.end(), bind<void>(ref(acc), _1));
std::cout << " min""(acc) = " << (min)(acc) << std::endl; // Extra quotes are to prevent complaints from Boost inspect tool
std::cout << " mean(acc) = " << mean(acc) << std::endl;
// since mean depends on count and sum, we can get their results, too.
std::cout << " count(acc) = " << count(acc) << std::endl;
std::cout << " sum(acc) = " << sum(acc) << std::endl;
std::cout << " moment<2>(acc) = " << accumulators::moment<2>(acc) << std::endl;
}
///////////////////////////////////////////////////////////////////////////////
// example2
//
// Calculate some tail statistics. This demonstrates how to specify
// constructor and accumulator parameters. Note that the tail statistics
// return multiple values, which are returned in an iterator_range.
//
// It pushes data in and displays the intermediate results to demonstrate
// how the tail statistics are updated.
void example2()
{
// An accumulator which tracks the right tail (largest N items) and
// some data that are covariate with them. N == 4.
accumulator_set<
double
, stats<tag::tail_variate<double, tag::covariate1, right> >
> acc(tag::tail<right>::cache_size = 4);
acc(2.1, covariate1 = .21);
acc(1.1, covariate1 = .11);
acc(2.1, covariate1 = .21);
acc(1.1, covariate1 = .11);
std::cout << " tail = "; output_range(tail(acc));
std::cout << " tail_variate = "; output_range(tail_variate(acc));
std::cout << std::endl;
acc(21.1, covariate1 = 2.11);
acc(11.1, covariate1 = 1.11);
acc(21.1, covariate1 = 2.11);
acc(11.1, covariate1 = 1.11);
std::cout << " tail = "; output_range(tail(acc));
std::cout << " tail_variate = "; output_range(tail_variate(acc));
std::cout << std::endl;
acc(42.1, covariate1 = 4.21);
acc(41.1, covariate1 = 4.11);
acc(42.1, covariate1 = 4.21);
acc(41.1, covariate1 = 4.11);
std::cout << " tail = "; output_range(tail(acc));
std::cout << " tail_variate = "; output_range(tail_variate(acc));
std::cout << std::endl;
acc(32.1, covariate1 = 3.21);
acc(31.1, covariate1 = 3.11);
acc(32.1, covariate1 = 3.21);
acc(31.1, covariate1 = 3.11);
std::cout << " tail = "; output_range(tail(acc));
std::cout << " tail_variate = "; output_range(tail_variate(acc));
}
///////////////////////////////////////////////////////////////////////////////
// example3
//
// Demonstrate how to calculate weighted statistics. This example demonstrates
// both a simple weighted statistical calculation, and a more complicated
// calculation where the weight statistics are calculated and stored in an
// external weight accumulator.
void example3()
{
// weight == double
double w = 1.;
// Simple weighted calculation
{
// stats that depend on the weight are made external
accumulator_set<double, stats<tag::mean>, double> acc;
acc(0., weight = w);
acc(1., weight = w);
acc(-1., weight = w);
acc(3.14159, weight = w);
std::cout << " mean(acc) = " << mean(acc) << std::endl;
}
// Weighted calculation with an external weight accumulator
{
// stats that depend on the weight are made external
accumulator_set<double, stats<tag::mean>, external<double> > acc;
// Here's an external weight accumulator
accumulator_set<void, stats<tag::sum_of_weights>, double> weight_acc;
weight_acc(weight = w); acc(0., weight = w);
weight_acc(weight = w); acc(1., weight = w);
weight_acc(weight = w); acc(-1., weight = w);
weight_acc(weight = w); acc(3.14159, weight = w);
std::cout << " mean(acc) = " << mean(acc, weights = weight_acc) << std::endl;
}
}
///////////////////////////////////////////////////////////////////////////////
// example4
//
// Show how accumulators could be persisted into a file, and then continued
// from where they were left of
//
void example4()
{
accumulator_set<
double
, stats<tag::min, tag::mean(immediate), tag::sum, tag::moment<2>, tag::p_square_quantile, tag::kurtosis >
> acc(quantile_probability = 0.9);
{
// accumulate values from array
boost::array<double, 10> data = {-10., -8., -7., -6., -5., -4., -3., -2., -1., 0.};
acc = std::for_each(data.begin(), data.end(), acc);
}
std::cout << " min = " << (min)(acc) << std::endl;
std::cout << " mean = " << mean(acc) << std::endl;
std::cout << " count = " << count(acc) << std::endl;
std::cout << " sum = " << sum(acc) << std::endl;
std::cout << " moment<2> = " << accumulators::moment<2>(acc) << std::endl;
std::cout << " p_square_quantile = " << accumulators::p_square_quantile(acc) << std::endl;
std::cout << " kurtosis = " << accumulators::kurtosis(acc) << std::endl;
// save accumulator list into a file called "saved-stats"
const unsigned ACC_VER = 0;
const char* file_name = "saved-stats";
{
std::ofstream ofs(file_name);
boost::archive::text_oarchive oa(ofs);
acc.serialize(oa, ACC_VER);
}
// create a new accumulator set and initialize from data saved into the file
accumulator_set<
double
, stats<tag::min, tag::mean(immediate), tag::sum, tag::moment<2>, tag::p_square_quantile, tag::kurtosis >
> restored_acc(quantile_probability = 0.9);
{
std::ifstream ifs(file_name);
boost::archive::text_iarchive ia(ifs);
restored_acc.serialize(ia, ACC_VER);
}
// continue accumulating into both sets
{
// accumulate values from array
boost::array<double, 10> data = {10., 8., 7., 6., 5., 4., 3., 2., 1., 0.};
acc = std::for_each(data.begin(), data.end(), acc);
restored_acc = std::for_each(data.begin(), data.end(), restored_acc);
}
// validate that both return th same values
std::cout << std::endl << "Values in original set:" << std::endl;
std::cout << " min""(acc) = " << (min)(acc) << std::endl;
std::cout << " mean(acc) = " << mean(acc) << std::endl;
std::cout << " count(acc) = " << count(acc) << std::endl;
std::cout << " sum(acc) = " << sum(acc) << std::endl;
std::cout << " moment<2>(acc) = " << accumulators::moment<2>(acc) << std::endl;
std::cout << " p_square_quantile(acc) = " << accumulators::p_square_quantile(acc) << std::endl;
std::cout << " kurtosis(acc) = " << accumulators::kurtosis(acc) << std::endl;
std::cout << std::endl << "Values in restored set:" << std::endl;
std::cout << " min""(acc) = " << (min)(restored_acc) << std::endl;
std::cout << " mean(acc) = " << mean(restored_acc) << std::endl;
std::cout << " count(acc) = " << count(restored_acc) << std::endl;
std::cout << " sum(acc) = " << sum(restored_acc) << std::endl;
std::cout << " moment<2>(acc) = " << accumulators::moment<2>(restored_acc) << std::endl;
std::cout << " p_square_quantile(acc) = " << accumulators::p_square_quantile(restored_acc) << std::endl;
std::cout << " kurtosis(acc) = " << accumulators::kurtosis(restored_acc) << std::endl;
}
///////////////////////////////////////////////////////////////////////////////
// main
int main()
{
std::cout << "Example 1:\n";
example1();
std::cout << "\nExample 2:\n";
example2();
std::cout << "\nExample 3:\n";
example3();
std::cout << "\nExample 4:\n";
example4();
return 0;
}