tests/framework/instruments/InstrumentsStats.cpp

/*
 * Copyright (c) 2018 ARM Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 * SOFTWARE.
 */
#include "InstrumentsStats.h"

namespace arm_compute
{
namespace test
{
namespace framework
{
InstrumentsStats::InstrumentsStats(const std::vector<Measurement> &measurements)
    : _min(nullptr), _max(nullptr), _median(nullptr), _mean(measurements.begin()->value().is_floating_point), _stddev(0.0)
{
    auto cmp_measurements = [](const Measurement & a, const Measurement & b)
    {
        return a.value() < b.value();
    };

    auto add_measurements = [](Measurement::Value a, const Measurement & b)
    {
        return a + b.value();
    };

    //Calculate min & max
    const auto values = std::minmax_element(measurements.begin(), measurements.end(), cmp_measurements);
    _min              = &(*values.first);
    _max              = &(*values.second);

    // Calculate the median value
    auto copy = measurements;
    std::nth_element(copy.begin(), copy.begin() + (copy.size() / 2), copy.end(), cmp_measurements);
    _median = &copy[copy.size() / 2];

    Measurement::Value sum_values = std::accumulate(measurements.begin(), measurements.end(), Measurement::Value(_min->value().is_floating_point), add_measurements);

    // Calculate the relative standard deviation
    _mean = sum_values / measurements.size();
    std::vector<Measurement::Value> diff(measurements.size(), _min->value().is_floating_point);
    std::transform(measurements.begin(), measurements.end(), diff.begin(), [&](const Measurement & x)
    {
        return x.value() - _mean;
    });
    auto sq_sum   = std::inner_product(diff.begin(), diff.end(), diff.begin(), Measurement::Value(_min->value().is_floating_point));
    auto variance = sq_sum / measurements.size();
    _stddev       = Measurement::Value::relative_standard_deviation(variance, _mean);
}
} // namespace framework
} // namespace test
} // namespace arm_compute