Method qubitMeasure

Core/VirtualQuantumProcessor/CPUImplQPU.cpp:141–195

template <typename data_t >
bool CPUImplQPU<data_t>::qubitMeasure(size_t qn)
{
    int64_t size = 1ll << (m_qubit_num - 1);
    int64_t offset = 1ll << qn;
    double dprob = 0;

    if (size > m_threshold)
    {
#pragma omp parallel for reduction (+:dprob)
        for (int64_t i = 0; i < size; i++)
        {
            int64_t real00_idx = _insert(i, qn);
            dprob += std::norm(m_state[real00_idx]);
        }
    }
    else
    {
        for (int64_t i = 0; i < size; i++)
        {
            int64_t real00_idx = _insert(i, qn);
            dprob += std::norm(m_state[real00_idx]);
        }
    }


    bool measure_out = random_generator19937() > dprob?true:false;

    if (!measure_out)
    {
        dprob = 1 / sqrt(dprob);

#pragma omp parallel for num_threads(_omp_thread_num(size))
        for (int64_t i = 0; i < size; i++)
        {
            int64_t real00_idx = _insert(i, qn);
            m_state[real00_idx] *= dprob;
            m_state[real00_idx | offset] = 0;
        }
       
    }
    else
    {
        dprob = 1 / sqrt(1 - dprob);

#pragma omp parallel for num_threads(_omp_thread_num(size))
        for (int64_t i = 0; i < size; i++)
        {
            int64_t real00_idx = _insert(i, qn);
            m_state[real00_idx] = 0;
            m_state[real00_idx | offset] *= dprob;
        }
        
    }
    return measure_out;
}

template <typename data_t>
std::vector<std::complex<data_t>> CPUImplQPU<data_t>::convert(const QStat& v) const