Function getRandomDensityMatrix

tests/utils/random.cpp:308–323

qmatrix getRandomDensityMatrix(int numQb) {
    DEMAND( numQb > 0 );
    
    // generate random probabilities to weight random pure states
    int dim = getPow2(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] * getOuterProduct(pure, pure);
    }
    
    return dens;
}


qmatrix getRandomPureDensityMatrix(int numQb) {