ihistogram.cpp
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/* Copyright (C) 2019
*
* This file is part of the osdev components suite
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "ihistogram.h"
// std
#include <algorithm>
#include <iomanip>
#include <numeric>
#include <sstream>
namespace osdev {
namespace components {
namespace mqtt {
namespace measurement {
IHistogram::~IHistogram() = default;
namespace {
std::pair<int, std::size_t> largestValueUnderThreshold(const std::vector<std::size_t>& hist, double thresholdValue)
{
int bin = -1;
std::size_t maxValue = 0;
// do not use the outlier bins for this calculation.
for (std::size_t i = 1; i < hist.size() - 1; ++i) {
if (hist[i] > maxValue && hist[i] < thresholdValue) {
bin = static_cast<int>(i);
maxValue = hist[i];
}
}
return { bin, maxValue };
}
} // namespace
std::string visualizeHistogram(const IHistogram& histogram)
{
const std::size_t diagramHeight = 10;
auto histData = histogram.histogramData(); // take a snapshot of the histogram data.
const auto& hist = histData.data();
std::ostringstream oss;
oss << "Histogram for " << histogram.id() << "\\n";
auto minmax = std::minmax_element(hist.begin(), hist.end());
auto minCountValueString = std::to_string(*minmax.first);
auto maxCountValueString = std::to_string(*minmax.second);
auto countValueFieldWidth = static_cast<std::int32_t>(std::max(minCountValueString.size(), maxCountValueString.size()));
auto verticalSize = (*minmax.second - *minmax.first) / static_cast<double>(diagramHeight);
auto totalMeasurements = std::accumulate(hist.begin(), hist.end(), 0);
oss << "Total nr of measurements: " << totalMeasurements << ", Nr of buckets: " << histogram.numBuckets() << ", bucket width: " << histogram.bucketWidth() << ", vertical resolution: " << verticalSize << "\\n";
auto binValuePair = largestValueUnderThreshold(hist, verticalSize);
if (binValuePair.first >= 0) {
oss << "Largest value under threshold: " << binValuePair.second << " in bin " << binValuePair.first << "\\n";
}
if (hist.front() > 0) {
oss << "Outliers to the left: " << hist.front() << ", smallest value: " << histData.smallestValueString() << histogram.unit() << "\\n";
}
if (hist.back() > 0) {
oss << "Outliers to the right: " << hist.back() << ", largest value: " << histData.largestValueString() << histogram.unit() << "\\n";
}
oss << "\\nSince last clear:\\n"
<< " number of values : " << histData.numberOfValuesSinceLastClear() << "\\n"
<< " smallest value : " << histData.smallestValueSinceLastClearString() << histogram.unit() << "\\n"
<< " largest value : " << histData.largestValueSinceLastClearString() << histogram.unit() << "\\n"
<< " average value : " << histData.averageValueSinceLastClearString() << histogram.unit() << "\\n\\n";
oss << std::setw(countValueFieldWidth) << maxCountValueString << " |";
for (std::size_t line = 0; line < diagramHeight; ++line) {
for (const auto& cnt : hist) {
if ((cnt - *minmax.first) > (diagramHeight - line - 1) * verticalSize) {
oss << '*';
}
else {
oss << ' ';
}
}
oss << "|\\n";
if (line + 1 < diagramHeight) {
oss << std::setw(countValueFieldWidth + 2) << '|';
}
}
oss << std::setw(countValueFieldWidth) << minCountValueString << " |/" << std::string(hist.size() - 2, '-') << "\\| " << histogram.unit() << "\\n";
auto minValueString = histogram.minValueString();
auto maxValueString = histogram.maxValueString();
auto valueFieldWidth = std::max(minValueString.size(), maxValueString.size());
for (std::size_t line = 0; line < valueFieldWidth; ++line) {
oss << std::setw(countValueFieldWidth + 3 + static_cast<int>(line)) << "";
oss << (line < minValueString.size() ? minValueString[line] : ' ');
if (line < maxValueString.size()) {
oss << std::string(histogram.numBuckets() - 1, ' ') << maxValueString[line];
}
oss << "\\n";
}
// Add the non zero data to the log for later analysis
// format: binnumber:value;binnumber:value;....
bool first = true;
for (std::size_t idx = 0; idx < hist.size(); ++idx) {
if (hist[idx] > 0) {
if (!first) {
oss << ';';
}
else {
oss << "\\n";
first = false;
}
oss << idx << ':' << hist[idx];
}
}
return oss.str();
}
std::ostream& operator<<(std::ostream& os, const IHistogram& rhs)
{
return os << rhs.toString();
}
} // End namespace measurement
} // End namespace mqtt
} // End namespace components
} // End namespace osdev