compute_percentile_statistic()

std::vector< double > MayaFlux::Yantra::compute_percentile_statistic	(	std::span< const double >	data,
		const size_t	num_windows,
		const uint32_t	hop_size,
		const uint32_t	window_size,
		double	percentile
	)

Compute percentile statistic using zero-copy processing.

This function computes an arbitrary percentile for a given data span. It finds the specified percentile value in each window.

Parameters

data	Input data span
num_windows	Number of windows to process
hop_size	Hop size for windowing
window_size	Size of each window
percentile	Percentile value (0-100)

Returns

Vector of percentile values

Definition at line 537 of file AnalysisHelper.cpp.

{
    std::vector<double> percentile_values(num_windows);
 
    if (percentile < 0.0)
        percentile = 0.0;
    if (percentile > 100.0)
        percentile = 100.0;
 
    std::vector<size_t> indices(num_windows);
    std::iota(indices.begin(), indices.end(), 0);
 
    std::for_each(std::execution::par_unseq, indices.begin(), indices.end(),
        [&](size_t i) {
            const size_t start_idx = i * hop_size;
            const size_t end_idx = std::min(start_idx + window_size, data.size());
            auto window = data.subspan(start_idx, end_idx - start_idx);
 
            if (window.empty()) {
                percentile_values[i] = 0.0;
                return;
            }
 
            std::vector<double> sorted_window(window.begin(), window.end());
            std::ranges::sort(sorted_window);
 
            if (percentile == 0.0) {
                percentile_values[i] = sorted_window.front();
                return;
            }
            if (percentile == 100.0) {
                percentile_values[i] = sorted_window.back();
                return;
            }
 
            double index = (percentile / 100.0) * static_cast<double>(sorted_window.size() - 1);
            auto lower_idx = static_cast<size_t>(std::floor(index));
            auto upper_idx = static_cast<size_t>(std::ceil(index));
 
            if (lower_idx == upper_idx) {
                percentile_values[i] = sorted_window[lower_idx];
            } else {
                double weight = index - static_cast<double>(lower_idx);
                percentile_values[i] = sorted_window[lower_idx] * (1.0 - weight) + sorted_window[upper_idx] * weight;
            }
        });
 
    return percentile_values;
}

References compute_percentile_statistic().

Referenced by compute_percentile_statistic(), MayaFlux::Yantra::StatisticalAnalyzer< InputType, OutputType >::compute_statistical_values(), and MayaFlux::Yantra::StatisticalAnalyzer< InputType, OutputType >::create_analysis_result().

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