Ejemplo n.º 1
0
void Sinusoid::generate(RNG& rng)
{
    A = exp(0.1*rng.randn());
    log10_period = -rng.rand();
    phi = 2.0 * M_PI * rng.rand();

    calculate_mu();

    for(size_t i=0; i<N; ++i)
        y[i] = mu[i] + sigma*rng.randn();

    calculate_logl();
}
Ejemplo n.º 2
0
void Sinusoid::generate(RNG& rng)
{
    A = -log(1.0 - rng.rand());
    log10_period = log10(1E-3 * t_range) + 3.0 * rng.rand();
    phi = 2.0 * M_PI * rng.rand();

    for(double& nn : n)
        nn = rng.randn();

    assemble();
}
Ejemplo n.º 3
0
double Sinusoid::perturb(RNG& rng)
{
    double logH = 0.0;

    if(rng.rand() < 0.5)
    {
        // Perturb one of the three parameters
        int which = rng.rand_int(3);
        if(which == 0)
        {
            A = 1.0 - exp(-A);
            A += rng.randh();
            wrap(A, 0.0, 1.0);
            A = -log(1.0 - A);
        }
        else if(which == 1)
        {
            log10_period += 3.0 * rng.randh();
            wrap(log10_period, log10(1E-3 * t_range), log10(t_range));
        }
        else
        {
            phi += 2 * M_PI * rng.randh();
            wrap(phi, 0.0, 2 * M_PI);
        }
    }
    else
    {
        // Perturb some of the ns.
        if(rng.rand() <= 0.5)
        {
            // Just change one
            int which = rng.rand_int(N);
            logH -= -0.5*pow(n[which], 2);
            n[which] += rng.randh();
            logH += -0.5*pow(n[which], 2);
        }
        else
        {
            // Potentially regenerate many
            int reps = pow(N, rng.rand());
            for(int i=0; i<reps; ++i)
                n[rng.rand_int(N)] = rng.randn();
        }

    }

    assemble();

    return logH;
}
Ejemplo n.º 4
0
double Sinusoid::perturb(RNG& rng)
{
    double logH = 0.0;

    int proposal_type = 1;//rng.rand_int(4);

    if(proposal_type == 0)
    {
        // Perturb parameters, changing data along with it
        std::vector<double> mu_old = mu;

        logH += perturb_parameters(rng);
        calculate_mu();

        double n;
        for(size_t i=0; i<N; ++i)
        {
            n = (y[i] - mu_old[i]) / sigma;
            y[i] = mu[i] + sigma * n;
        }

        calculate_logl();
    }
    else if(proposal_type == 1)
    {
        // Perturb parameters, keeping data constant
        // (aka Metropolis step of the posterior!)
        logH -= logl;

        logH += perturb_parameters(rng);

        calculate_mu();
        calculate_logl();

        logH += logl;        
    }
    else if(proposal_type == 2)
    {
        // Just change one datum
        int which = rng.rand_int(N);

        logH -= -0.5*pow((y[which] - mu[which])/sigma, 2);
        y[which] += sigma * rng.randh();
        logH += -0.5*pow((y[which] - mu[which])/sigma, 2);

        calculate_logl();
    }
    else
    {
        // Potentially regenerate many of the data points
        int reps = pow(N, rng.rand());
        int which;
        for(int i=0; i<reps; ++i)
        {
            which = rng.rand_int(N);
            y[which] = mu[which] + sigma * rng.randn();
        }

        calculate_logl();
    }

    return logH;
}