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change core meson config to include CatalogueAPI depends
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DataSeriesUtils.h
317 lines | 13.8 KiB | text/x-c | CLexer
#ifndef SCIQLOP_DATASERIESUTILS_H
#define SCIQLOP_DATASERIESUTILS_H
#include "CoreGlobal.h"
#include <Common/SortUtils.h>
#include <Data/DataSeriesIterator.h>
#include <QLoggingCategory>
#include <cmath>
Q_DECLARE_LOGGING_CATEGORY(LOG_DataSeriesUtils)
/**
* Utility class with methods for data series
*/
struct SCIQLOP_CORE_EXPORT DataSeriesUtils {
/**
* Define a meshs.
*
* A mesh is a regular grid representing cells of the same width (in x) and of the same height
* (in y). At each mesh point is associated a value.
*
* Each axis of the mesh is defined by a minimum value, a number of values is a mesh step.
* For example: if min = 1, nbValues = 5 and step = 2 => the axis of the mesh will be [1, 3, 5,
* 7, 9].
*
* The values are defined in an array of size {nbX * nbY}. The data is stored along the X axis.
*
* For example, the mesh:
* Y = 2 [ 7 ; 8 ; 9
* Y = 1 4 ; 5 ; 6
* Y = 0 1 ; 2 ; 3 ]
* X = 0 X = 1 X = 2
*
* will be represented by data [1, 2, 3, 4, 5, 6, 7, 8, 9]
*/
struct Mesh {
explicit Mesh() = default;
explicit Mesh(int nbX, double xMin, double xStep, int nbY, double yMin, double yStep)
: m_NbX{nbX},
m_XMin{xMin},
m_XStep{xStep},
m_NbY{nbY},
m_YMin{yMin},
m_YStep{yStep},
m_Data(nbX * nbY)
{
}
inline bool isEmpty() const { return m_Data.size() == 0; }
inline double xMax() const { return m_XMin + (m_NbX - 1) * m_XStep; }
inline double yMax() const { return m_YMin + (m_NbY - 1) * m_YStep; }
int m_NbX{0};
double m_XMin{};
double m_XStep{};
int m_NbY{0};
double m_YMin{};
double m_YStep{};
std::vector<double> m_Data{};
};
/**
* Represents a resolution used to generate the data of a mesh on the x-axis or in Y.
*
* A resolution is represented by a value and flag indicating if it's in the logarithmic scale
* @sa Mesh
*/
struct Resolution {
double m_Val{std::numeric_limits<double>::quiet_NaN()};
bool m_Logarithmic{false};
};
/**
* Processes data from a data series to complete the data holes with a fill value.
*
* A data hole is determined by the resolution passed in parameter: if, between two continuous
* data on the x-axis, the difference between these data is greater than the resolution, then
* there is one or more holes between them. The holes are filled by adding:
* - for the x-axis, new data corresponding to the 'step resolution' starting from the first
* data;
* - for values, a default value (fill value) for each new data added on the x-axis.
*
* For example, with :
* - xAxisData = [0, 1, 5, 7, 14 ]
* - valuesData = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] (two components per x-axis data)
* - fillValue = NaN
* - and resolution = 2;
*
* For the x axis, we calculate as data holes: [3, 9, 11, 13]. These holes are added to the
* x-axis data, and NaNs (two per x-axis data) are added to the values:
* => xAxisData = [0, 1, 3, 5, 7, 9, 11, 13, 14 ]
* => valuesData = [0, 1, 2, 3, NaN, NaN, 4, 5, 6, 7, NaN, NaN, NaN, NaN, NaN, NaN, 8, 9]
*
* It is also possible to set bounds for the data series. If these bounds are defined and exceed
* the limits of the data series, data holes are added to the series at the beginning and/or the
* end.
*
* The generation of data holes at the beginning/end of the data series is performed starting
* from the x-axis series limit and adding data holes at each 'resolution step' as long as the
* new bound is not reached.
*
* For example, with :
* - xAxisData = [3, 4, 5, 6, 7 ]
* - valuesData = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
* - fillValue = NaN
* - minBound = 0
* - maxBound = 12
* - and resolution = 2;
*
* => Starting from 3 and decreasing 2 by 2 until reaching 0 : a data hole at value 1 will be
* added to the beginning of the series
* => Starting from 7 and increasing 2 by 2 until reaching 12 : data holes at values 9 and 11
* will be added to the end of the series
*
* So :
* => xAxisData = [1, 3, 4, 5, 6, 7, 9, 11 ]
* => valuesData = [NaN, NaN, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, NaN, NaN, NaN, NaN]
*
* @param xAxisData the x-axis data of the data series
* @param valuesData the values data of the data series
* @param resolution the resoultion (on x-axis) used to determinate data holes
* @param fillValue the fill value used for data holes in the values data
* @param minBound the limit at which to start filling data holes for the series. If set to NaN,
* the limit is not used
* @param maxBound the limit at which to end filling data holes for the series. If set to NaN,
* the limit is not used
*
* @remarks There is no control over the consistency between x-axis data and values data. The
* method considers that the data is well formed (the total number of values data is a multiple
* of the number of x-axis data)
*/
static void fillDataHoles(std::vector<double> &xAxisData, std::vector<double> &valuesData,
double resolution,
double fillValue = std::numeric_limits<double>::quiet_NaN(),
double minBound = std::numeric_limits<double>::quiet_NaN(),
double maxBound = std::numeric_limits<double>::quiet_NaN());
/**
* Computes the resolution of a dataset passed as a parameter.
*
* The resolution of a dataset is the minimum difference between two values that follow in the
* set.
* For example:
* - for the set [0, 2, 4, 8, 10, 11, 13] => the resolution is 1 (difference between 10 and 11).
*
* A resolution can be calculated on the logarithmic scale (base of 10). In this case, the
* dataset is first converted to logarithmic values.
* For example:
* - for the set [10, 100, 10000, 1000000], the values are converted to [1, 2, 4, 6] => the
* logarithmic resolution is 1 (difference between 1 and 2).
*
* @param begin the iterator pointing to the beginning of the dataset
* @param end the iterator pointing to the end of the dataset
* @param logarithmic computes a logarithmic resolution or not
* @return the resolution computed
* @warning the method considers the dataset as sorted and doesn't control it.
*/
template <typename Iterator>
static Resolution resolution(Iterator begin, Iterator end, bool logarithmic = false);
/**
* Computes a regular mesh for a data series, according to resolutions for x-axis and y-axis
* passed as parameters.
*
* The mesh is created from the resolutions in x and y and the boundaries delimiting the data
* series. If the resolutions do not allow to obtain a regular mesh, they are recalculated.
*
* For example :
* Let x-axis data = [0, 1, 3, 5, 9], its associated values ​​= [0, 10, 30, 50, 90] and
* xResolution = 2.
* Based on the resolution, the mesh would be [0, 2, 4, 6, 8, 10] and would be invalid because
* it exceeds the maximum bound of the data. The resolution is thus recalculated so that the
* mesh holds between the data terminals.
* So => resolution is 1.8 and the mesh is [0, 1.8, 3.6, 5.4, 7.2, 9].
*
* Once the mesh is generated in x and y, the values ​​are associated with each mesh point,
* based on the data in the series, finding the existing data at which the mesh point would be
* or would be closest to, without exceeding it.
*
* In the example, we determine the value of each mesh point:
* - x = 0 => value = 0 (existing x in the data series)
* - x = 1.8 => value = 10 (the closest existing x: 1)
* - x = 3.6 => value = 30 (the closest existing x: 3)
* - x = 5.4 => value = 50 (the closest existing x: 5)
* - x = 7.2 => value = 50 (the closest existing x: 5)
* - x = 9 => value = 90 (existing x in the data series)
*
* Same algorithm is applied for y-axis.
*
* @param begin the iterator pointing to the beginning of the data series
* @param end the iterator pointing to the end of the data series
* @param xResolution the resolution expected for the mesh's x-axis
* @param yResolution the resolution expected for the mesh's y-axis
* @return the mesh created, an empty mesh if the input data do not allow to generate a regular
* mesh (empty data, null resolutions, logarithmic x-axis)
* @warning the method considers the dataset as sorted and doesn't control it.
*/
static Mesh regularMesh(DataSeriesIterator begin, DataSeriesIterator end,
Resolution xResolution, Resolution yResolution);
/**
* Calculates the min and max thresholds of a dataset.
*
* The thresholds of a dataset correspond to the min and max limits of the set to which the
* outliers are exluded (values distant from the others) For example, for the set [1, 2, 3, 4,
* 5, 10000], 10000 is an outlier and will be excluded from the thresholds.
*
* Bounds determining the thresholds is calculated according to the mean and the standard
* deviation of the defined data. The thresholds are limited to the min / max values of the
* dataset: if for example the calculated min threshold is 2 but the min value of the datasetset
* is 4, 4 is returned as the min threshold.
*
* @param begin the beginning of the dataset
* @param end the end of the dataset
* @param logarithmic computes threshold with a logarithmic scale or not
* @return the thresholds computed, a couple of nan values if it couldn't be computed
*/
template <typename Iterator>
static std::pair<double, double> thresholds(Iterator begin, Iterator end,
bool logarithmic = false);
};
template <typename Iterator>
DataSeriesUtils::Resolution DataSeriesUtils::resolution(Iterator begin, Iterator end,
bool logarithmic)
{
// Retrieves data into a work dataset
using ValueType = typename Iterator::value_type;
std::vector<ValueType> values{};
std::copy(begin, end, std::back_inserter(values));
// Converts data if logarithmic flag is activated
if (logarithmic) {
std::for_each(values.begin(), values.end(),
[logarithmic](auto &val) { val = std::log10(val); });
}
// Computes the differences between the values in the dataset
std::adjacent_difference(values.begin(), values.end(), values.begin());
// Retrieves the smallest difference
auto resolutionIt = std::min_element(values.begin(), values.end());
auto resolution
= resolutionIt != values.end() ? *resolutionIt : std::numeric_limits<double>::quiet_NaN();
return Resolution{resolution, logarithmic};
}
template <typename Iterator>
std::pair<double, double> DataSeriesUtils::thresholds(Iterator begin, Iterator end,
bool logarithmic)
{
/// Lambda that converts values in case of logaritmic scale
auto toLog = [logarithmic](const auto &value) {
if (logarithmic) {
// Logaritmic scale doesn't include zero value
return !(std::isnan(value) || value < std::numeric_limits<double>::epsilon())
? std::log10(value)
: std::numeric_limits<double>::quiet_NaN();
}
else {
return value;
}
};
/// Lambda that converts values to linear scale
auto fromLog
= [logarithmic](const auto &value) { return logarithmic ? std::pow(10, value) : value; };
/// Lambda used to sum data and divide the sum by the number of data. It is used to calculate
/// the mean and standard deviation
/// @param fun the data addition function
auto accumulate = [begin, end](auto fun) {
double sum;
int nbValues;
std::tie(sum, nbValues) = std::accumulate(
begin, end, std::make_pair(0., 0), [fun](const auto &input, const auto &value) {
auto computedValue = fun(value);
// NaN values are excluded from the sum
return !std::isnan(computedValue)
? std::make_pair(input.first + computedValue, input.second + 1)
: input;
});
return nbValues != 0 ? sum / nbValues : std::numeric_limits<double>::quiet_NaN();
};
// Computes mean
auto mean = accumulate([toLog](const auto &val) { return toLog(val); });
if (std::isnan(mean)) {
return {std::numeric_limits<double>::quiet_NaN(), std::numeric_limits<double>::quiet_NaN()};
}
// Computes standard deviation
auto variance
= accumulate([mean, toLog](const auto &val) { return std::pow(toLog(val) - mean, 2); });
auto sigma = std::sqrt(variance);
// Computes thresholds
auto minThreshold = fromLog(mean - 3 * sigma);
auto maxThreshold = fromLog(mean + 3 * sigma);
// Finds min/max values
auto minIt = std::min_element(begin, end, [toLog](const auto &it1, const auto &it2) {
return SortUtils::minCompareWithNaN(toLog(it1), toLog(it2));
});
auto maxIt = std::max_element(begin, end, [toLog](const auto &it1, const auto &it2) {
return SortUtils::maxCompareWithNaN(toLog(it1), toLog(it2));
});
// Returns thresholds (bounded to min/max values)
return {std::max(*minIt, minThreshold), std::min(*maxIt, maxThreshold)};
}
#endif // SCIQLOP_DATASERIESUTILS_H