Exemplo n.º 1
0
int main(int argc, char*argv[])
{

    randomizeStart();
    srand(time(0));

    unsigned int nDimensions=2;
    double domainMin =-10;
    double domainMax = 10;
    double domainStep= 0.1;

    vector < pair<double, double> > domain;

    double dgranularity= (abs(domainMax-domainMin))/domainStep;
    unsigned int granularity = floor(dgranularity+0.5);
    unsigned int nGibbsBurnIn=0;
    unsigned int nGibbsValid=1000;

    domain.resize(nDimensions);
    for (unsigned int i=0; i<nDimensions; i++)
        domain[i] = pair<double,double>(domainMin,domainMax);

    DMultivariateGaussian model(nDimensions);

    Inferencer inferencer;
    inferencer.init( &model, nDimensions,granularity, domainStep, domain );
    /*
    for ( unsigned i=1000; i<=5000; i+=500)
    {
    inferencer.init( &model, nDimensions,granularity, domainStep, domain );
    cerr << i << " " << inferencer.gibbsSamplingIntegral(nGibbsBurnIn,i) << endl;
    }
    */

    Sampler sampler;
    VectorXd cdf(2000),pdf(2000);

    double x=-6;
    double delta=abs(x)/1000.0;
    for ( int i=0; i<2000; i++)
    {
        pdf(i) = exp(-(0.5*(x*x) ));
        //cout << x << " " << exp(-(0.5*(x*x) )) << endl;
        x+=delta;
    }

    pdf*=1.0/(sqrt(2*M_PI));

    cout << sampler.fullIntegrate(pdf,delta) << endl;
    //cerr << cdf.sum()*delta << endl;
    sampler.discreteCumulativeDistribution(pdf,cdf);
    for ( int i=0; i<10; i++)
        sampler.inverseCumulativeSampling(cdf,delta);

    /*
    x=-5;
    double sum=cdf.sum();
    cdf/=(sum/(1000.0));
    for ( int i=0; i<2000; i++)
    {
            cout << x << " " << cdf(i) << endl;
            x+=delta;
    }

    for ( int i=0; i<100000; i++)
            cerr << sampler.inverseCumulativeSampling(cdf,delta) << endl;
    */
    return 0;
}