Algorithm-RandomPointGenerator

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lib/Algorithm/RandomPointGenerator.pm  view on Meta::CPAN

    my ($class, %args) = @_;
    my @params = keys %args;
    croak "\nYou have used a wrong name for a keyword argument " .
          "--- perhaps a misspelling\n" 
          if check_for_illegal_params(@params) == 0;
    bless {
        _hist_file           =>   $args{input_histogram_file}    || croak("histogram file required"),
        _bbox_file           =>   $args{bounding_box_file}       || croak("bounding box file required"),
        _N                   =>   $args{number_of_points}               || 2000,
        _how_many_to_discard =>   $args{how_many_to_discard}            || 500,
        _debug               =>   $args{debug}                          || 0,
        _proposal_density_width    =>   $args{proposal_density_width}   || 0.1, 
        _y_axis_pos_direction      =>   $args{y_axis_pos_direction}     || "down",
        _output_hist_bins_along_x  =>   $args{output_hist_bins_along_x} || 40,
        _command_line_mode         =>   $args{command_line_mode}        || 0,
        _x_delta             =>   undef,
        _y_delta             =>   undef,
        _input_histogram     =>   undef,
        _output_histogram    =>   undef,
        _bounding_box        =>   undef,
        _generated_points    =>   undef,

lib/Algorithm/RandomPointGenerator.pm  view on Meta::CPAN

# proposal density function.  The desired density is calculated by applying bilinear
# interpolation to the bin counts to the four nearest four points in the normalized
# version of the input histogram.
sub desired_density {
    my $self = shift;
    my $sample = shift;
    my $histref = $self->{_normalized_input_hist};
    my $bbsize = $self->{_bounding_box};
    my $horiz_delta = $self->{_x_delta};
    my $vert_delta = $self->{_y_delta};
    print "horiz_delta: $horiz_delta    vert_delta: $vert_delta\n" if $self->{_debug};
    return 0 if $sample->[0] < $bbsize->[0][0] || $sample->[0] > $bbsize->[0][1] ||
                $sample->[1] < $bbsize->[1][0] || $sample->[1] > $bbsize->[1][1];
    print "horizontal extent: $bbsize->[0][0]  $bbsize->[0][1]\n" if $self->{_debug};
    print "vertical extent: $bbsize->[1][0]  $bbsize->[1][1]\n" if $self->{_debug};
    my $bin_horiz = int( ($sample->[0] - $bbsize->[0][0]) / $horiz_delta );
    my $bin_vert = int( ($sample->[1] - $bbsize->[1][0]) / $vert_delta );
    print "bin 2D index: horiz: $bin_horiz   vert: $bin_vert  for sample value @$sample\n"
        if $self->{_debug};
    my $prob00 = $histref->[$bin_vert][$bin_horiz] || 0;
    return $prob00 if (($bin_horiz + 1) >= @{$histref->[0]}) || (($bin_vert + 1) >= @{$histref});
    my $prob01 = $histref->[$bin_vert + 1][$bin_horiz] || 0;
    my $prob10 = $histref->[$bin_vert][$bin_horiz+ 1] || 0;
    my $prob11 = $histref->[$bin_vert + 1][$bin_horiz + 1] || 0;
    print "The four probs: $prob00   $prob01   $prob10   $prob11\n" if $self->{_debug};
    my $horiz_fractional = (($sample->[0] - $bbsize->[0][0]) / $horiz_delta) - $bin_horiz; 
    my $vert_fractional = (($sample->[1] - $bbsize->[1][0]) / $vert_delta) - $bin_vert; 
    print "horiz frac: $horiz_fractional   vert frac: $vert_fractional\n" if $self->{_debug};
    my $interpolated_prob = $prob00 * (1 - $horiz_fractional) * (1 - $vert_fractional) +
                            $prob10 * $horiz_fractional * (1 - $vert_fractional) +   
                            $prob01 * (1 - $horiz_fractional) * $vert_fractional +   
                            $prob11 * $horiz_fractional * $vert_fractional;   
    print "Interpolated prob: $interpolated_prob\n" if $self->{_debug};
    return $interpolated_prob;
}

sub proposal_density {
    my $self = shift;
    my $sample = shift;
    my $mean = shift;
    my $sigmax = $self->{_sigmax_for_proposal_density};
    my $sigmay = $self->{_sigmay_for_proposal_density};
    my @SIGMA = ( [$sigmax, 0], [0, $sigmay] );

lib/Algorithm/RandomPointGenerator.pm  view on Meta::CPAN

sub check_for_illegal_params {
    my @params = @_;
    my @legal_params = qw / input_histogram_file
                            bounding_box_file
                            number_of_points
                            how_many_to_discard
                            proposal_density_width
                            y_axis_pos_direction
                            output_hist_bins_along_x
                            command_line_mode
                            debug
                          /;
    my $found_match_flag;
    foreach my $param (@params) {
        foreach my $legal (@legal_params) {
            $found_match_flag = 0;
            if ($param eq $legal) {
                $found_match_flag = 1;
                last;
            }
        }

lib/Algorithm/RandomPointGenerator.pm  view on Meta::CPAN

=item B<plot_histogram_lineplot():>

    $generator->plot_histogram_lineplot(); 

This creates a 3D line plot display of the histogram of the generated random points.

=item B<display_output_histogram_in_terminal_window():>

    $generator->display_output_histogram_in_terminal_window();

Useful for debugging purposes, it displays in the terminal window a two dimensional
array of numbers that is the histogram of the random points generated by the module.

=back

=head1 THE C<examples> DIRECTORY

Probably the most useful item in the C<examples> directory is the command-line script
C<genRand2D> that can be called simply with two arguments for generating a set of
random points.  A call to this script looks like