Function getRandomDensityMatrix

tests/deprecated/test_utilities.cpp:603–618

}

QMatrix getRandomDensityMatrix(int numQb) {
    DEMAND( numQb > 0 );
    
    // generate random probabilities to weight random pure states
    int dim = 1<<numQb;
    vector<qreal> probs = getRandomProbabilities(dim);
    
    // add random pure states
    QMatrix dens = getZeroMatrix(dim);
    for (int i=0; i<dim; i++) {
        QVector pure = getRandomStateVector(numQb);
        dens += probs[i] * getKetBra(pure, pure);
    }
    
    return dens;
}

QMatrix getPureDensityMatrix(QVector state) {
    return getKetBra(state, state);