Function getNormalised

tests/deprecated/test_utilities.cpp:557–579

}

QVector getNormalised(QVector vec) {

    // compute the vec norm via Kahan summation to suppress numerical error
    qreal norm = 0;
    qreal y, t, c;
    c = 0;
    
    for (size_t i=0; i<vec.size(); i++) {
        y = real(vec[i])*real(vec[i]) - c;
        t = norm + y;
        c = ( t - norm ) - y;
        norm = t;
        
        y = imag(vec[i])*imag(vec[i]) - c;
        t = norm + y;
        c = ( t - norm ) - y;
        norm = t;
    }
    
    for (size_t i=0; i<vec.size(); i++)
        vec[i] /= sqrt(norm);
    return vec;
}

QVector getRandomStateVector(int numQb) {
    return getNormalised(getRandomQVector(1<<numQb));