Function columnQuantile

src/backend/core/column/ColumnPrivate.cpp:2433–2487

}

double columnQuantile(double p, const std::string_view& variable, const std::weak_ptr<Parsing::Payload> payload) {
	const auto pd = std::dynamic_pointer_cast<PayloadColumn>(payload.lock());
	if (!pd) {
		assert(pd); // Debug build
		return NAN;
	}

	if (p < 0)
		return NAN;

	const Column* column = nullptr;
	for (const auto& formulaData : pd->formulaData) {
		if (formulaData.variableName().compare(QLatin1String(variable)) == 0) {
			column = formulaData.column();
			break;
		}
	}
	if (!column)
		return NAN;

	double value = 0.0;
	switch (column->columnMode()) { // all types
	case AbstractColumn::ColumnMode::Double: {
		auto data = reinterpret_cast<QVector<double>*>(column->data());
		value = nsl_stats_quantile(data->data(), 1, column->statistics().size, p, nsl_stats_quantile_type7);
		break;
	}
	case AbstractColumn::ColumnMode::Integer: {
		auto* intData = reinterpret_cast<QVector<int>*>(column->data());

		QVector<double> data = QVector<double>(); // copy data to double
		data.reserve(column->rowCount());
		for (auto v : *intData)
			data << static_cast<double>(v);
		value = nsl_stats_quantile(data.data(), 1, column->statistics().size, p, nsl_stats_quantile_type7);
		break;
	}
	case AbstractColumn::ColumnMode::BigInt: {
		auto* bigIntData = reinterpret_cast<QVector<qint64>*>(column->data());

		QVector<double> data = QVector<double>(); // copy data to double
		data.reserve(column->rowCount());
		for (auto v : *bigIntData)
			data << static_cast<double>(v);
		value = nsl_stats_quantile(data.data(), 1, column->statistics().size, p, nsl_stats_quantile_type7);
		break;
	}
	case AbstractColumn::ColumnMode::DateTime: // not supported yet
	case AbstractColumn::ColumnMode::Day:
	case AbstractColumn::ColumnMode::Month:
	case AbstractColumn::ColumnMode::Text:
		break;
	}
	return value;
}

double columnPercentile(double p, const std::string_view& variable, const std::weak_ptr<Parsing::Payload> payload) {
	return columnQuantile(p / 100., variable, payload);