//
// Created by fly on 2021/11/25.
//

#include "Pearson.h"
#include <numeric>
#include <cmath>

Pearson::Pearson(uint64_t index, const std::vector<double> &primary, const std::vector<double> &other, QObject *parent)
        :
        m_index(index),
        m_primary(primary),
        m_other(other),
        QObject(parent) {

}

void Pearson::run() {
    auto n = m_primary.size() * 1.0;
    double pearson = n * std::inner_product(m_primary.begin(), m_primary.end(), m_other.begin(), 0.0) -
                     std::accumulate(m_primary.begin(), m_primary.end(), 0.0) *
                     std::accumulate(m_other.begin(), m_other.end(), 0.0);

    double temp1 = n * std::inner_product(m_primary.begin(), m_primary.end(), m_primary.begin(), 0.0) -
                   std::pow(std::accumulate(m_primary.begin(), m_primary.end(), 0.0), 2.0);
    double temp2 = n * std::inner_product(m_other.begin(), m_other.end(), m_other.begin(), 0.0) -
                   std::pow(std::accumulate(m_other.begin(), m_other.end(), 0.0), 2.0);
    temp1 = std::sqrt(temp1);
    temp2 = std::sqrt(temp2);
    auto temp = (temp1 * temp2);
    if (temp != 0) {
        pearson = pearson / temp;
        if (!std::isnan(pearson)) {
            emit result(m_index, pearson);
        }
    }

    emit finished();
}