root/library/bdm/stat/discrete.cpp

#include "discrete.h"

namespace bdm {

void rectangular_support::set_parameters ( const Array<vec> &ranges0, const ivec &gridsize0 ) {
    ranges = ranges0;
    gridsizes = gridsize0;
    initialize();
}


void rectangular_support::initialize() {
    dim = ranges.length();
    bdm_assert ( gridsizes.length() == dim, "Incompatible dimensions of input" );
    Npoints = prod ( gridsizes );
    bdm_assert ( Npoints > 0, "Wrong input parameters" );

    //precompute steps
    steps.set_size ( dim );
    for ( int j = 0; j < dim; j++ ) {
        steps ( j ) = ( ranges ( j ) ( 1 ) - ranges ( j ) ( 0 ) ) / gridsizes ( j );
    }
    actvec.set_size ( dim );
    actvec_ind.set_size ( dim );
}

vec rectangular_support::get_vec ( const ivec &inds ) {
    vec v ( dim );
    for ( int j = 0; j < dim; j++ ) {
        bdm_assert_debug ( inds ( j ) < gridsizes ( j ), "Index out of bounds" );
        v ( j ) = ranges ( j ) ( 0 ) + ( 0.5 + inds ( j ) ) * steps ( j );
    }
    return v;
}

long rectangular_support::linear_index ( const ivec inds ) {
    long ind = 0;
    bdm_assert_debug ( inds.length() == dim, "Improper indices inds" );
    int dim_skips = 1; // skips in active dimension, in the first dimension, the skips are 1 index per value

    for ( int j = 0; j < dim; j++ ) {
        ind += dim_skips * ( inds ( j ) ); // add shift in linear index caused by this dimension
        dim_skips *= gridsizes ( j );  // indices in the next dimension are repeated with period gridsizes(j) times greater that in this dimesion
    }
    return ind;
}
const vec& rectangular_support::first_vec() {
    for ( int j = 0; j < dim; j++ ) {
        actvec ( j ) = ranges ( j ) ( 0 ) + 0.5 * steps ( j );
        actvec_ind ( j ) = 0;
    }
    actvolume = prod(steps);
    return actvec;
}
const vec& rectangular_support::next_vec() {
    // go through all dimensions
    int j = 0;
    while ( j < dim ) {
        if ( actvec_ind ( j ) == gridsizes ( j ) - 1 ) { //j-th index is full
            actvec_ind ( j ) = 0; //shift back
            actvec ( j ) = ranges ( j ) ( 0 ) + 0.5 * steps ( j );
            j++;
        } else {
            actvec_ind ( j ) ++;
            actvec ( j ) += steps ( j );
            break;
        }
    }
    // no need to set active volume
    return actvec;
}


ivec rectangular_support::nearest_point ( const vec &val ) {
    ivec inds;
    inds.set_size ( dim );
    for ( int j = 0; j < dim; j++ ) {
        if ( val ( j ) < ranges ( j ) ( 0 ) )
            inds ( j ) = 0;
        else {
            if ( val ( j ) > ranges ( j ) ( 1 ) )
                //! \todo GRIDSIZES prejmenovat..
                inds ( j ) = gridsizes ( j ) - 1;
            else {
                inds ( j ) = (int) ::round ( val ( j ) - ranges ( j ) ( 0 ) / steps ( j ) );
            }
        }
    }
    return inds;
}

void rectangular_support::from_setting ( const Setting &set ) {
    UI::get ( ranges , set, "ranges", UI::compulsory );
    UI::get ( gridsizes, set, "gridsizes", UI::compulsory );
    initialize();
}



void discrete_support::from_setting ( const Setting &set ) {
    UI::get ( Spoints, set, "points", UI::optional );
    if ( points() < 1 ) {
        int npoints;
        shared_ptr<epdf> ep = UI::build<epdf> ( set, "epdf", UI::compulsory );
        if ( !UI::get ( npoints, set, "npoints", UI::optional ) ) {
            npoints = 100;
        }

        //sample
        Spoints.set_size ( npoints );
        for ( int i = 0; i < points(); i++ ) {
            Spoints ( i ) = ep->sample();
        }
    }
    
    UI::get (volumes, set, "volumes",UI::optional);
        if (volumes.length()<1){
                volumes = 1.0/points()*ones(points());
        } 
        
}

void grid_fnc::set_values ( double ( *evalptr ) ( const vec& ) ) {
    if ( sup->points() > 0 ) {
        values ( 0 ) = ( *evalptr ) ( sup->first_vec() );
        for ( int j = 1; j < sup->points(); j++ ) {
            values ( j ) = ( *evalptr ) ( sup->next_vec() );
        }
    }
}

void grid_fnc::set_values ( const epdf &ep ) {
    if ( sup->points() > 0 ) {
        values ( 0 ) =  exp ( ep.evallog ( sup->first_vec() ) );
        for ( int j = 1; j < sup->points(); j++ ) {
            values ( j ) = exp ( ep.evallog ( sup->next_vec() ) );
        }
    }
}

double grid_fnc::integrate ( ) {
        double intgr=0.0;
        if ( sup->points() > 0 ) {
                sup->first_vec(); // also first volume
                intgr+= values(0) * sup->act_volume();
                for ( int j = 1; j < sup->points(); j++ ) {
                        sup->next_vec();
                        intgr+= values(j)*sup->act_volume();
                }
        }
        return intgr;
}

}