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lib/AI/Pathfinding/SMAstar.pm  view on Meta::CPAN

    return $self->{_state_successors_iterator};    
}

sub state_get_data_func {
    my $self = shift;
    if (@_) { $self->{_state_get_data_func} = shift }
    return $self->{_state_get_data_func};    
}

sub show_prog_func {
    my $self = shift;
    if (@_) { $self->{_show_prog_func} = shift }
    return $self->{_show_prog_func};    
}



###################################################################
#
# Add a state from which to begin the search.   There can 
# be multiple start-states.
#
###################################################################
sub add_start_state
{
    my ($self, $state) = @_;


    my $state_eval_func = $self->{_state_eval_func};
    my $state_goal_p_func = $self->{_state_goal_p_func};
    my $state_num_successors_func = $self->{_state_num_successors_func},
    my $state_successors_iterator = $self->{_state_successors_iterator},
    my $state_get_data_func = $self->{_state_get_data_func};
    
    # make sure required functions have been defined
    if(!defined($state_eval_func)){
	croak "SMAstar:  evaluation function is not defined\n";
    }
    if(!defined($state_goal_p_func)){
	croak "SMAstar:  goal function is not defined\n";
    }
    if(!defined($state_num_successors_func)){
	croak "SMAstar:  num successors function is not defined\n";
    }
   if(!defined($state_successors_iterator)){
	croak "SMAstar:  successor iterator is not defined\n";
    }

    # create a path object from this state
    my $state_obj = AI::Pathfinding::SMAstar::Path->new(
	_state           => $state,
	_eval_func      => $state_eval_func,
	_goal_p_func    => $state_goal_p_func,
	_num_successors_func => $state_num_successors_func,
	_successors_iterator => $state_successors_iterator,
	_get_data_func  => $state_get_data_func,
	);
    
    
    my $fcost = AI::Pathfinding::SMAstar::Path::fcost($state_obj);
    # check if the fcost of this node looks OK (is numeric)
    unless(Scalar::Util::looks_like_number($fcost)){
	croak "Error:  f-cost of state is not numeric.  Cannot add state to queue.\n";	
    }
    $state_obj->f_cost($fcost);

    # check if the num_successors function returns a number
    my $num_successors = $state_obj->get_num_successors();
    unless(Scalar::Util::looks_like_number($num_successors)){
	croak "Error:  Number of state successors is not numeric.  Cannot add state to queue.\n";	
    }

    # test out the iterator function to make sure it returns
    #  an object of the correct type
    my $classname = ref($state);
    my $test_successor_iterator = $state_obj->{_successors_iterator}->($state);
    my $test_successor = $test_successor_iterator->($state);
    my $succ_classname = ref($test_successor);

    unless($succ_classname eq $classname){
	croak "Error:  Successor iterator method of object $classname does " .
	    "not return an object of type $classname.\n";	
    }

    
    # add this node to the queue
    $self->{_priority_queue}->insert($state_obj);
 
}

###################################################################
#
# start the SMAstar search process
#
###################################################################
sub start_search
{
    my ($self, 
	$log_function,
	$str_function,
	$max_states_in_queue,
	$max_cost,
	) = @_;

    if(!defined($str_function)){
	croak "SMAstar start_search:  str_function is not defined.\n";
    }

    sma_star_tree_search(\($self->{_priority_queue}), 
                         \&AI::Pathfinding::SMAstar::Path::is_goal, 
                         \&AI::Pathfinding::SMAstar::Path::get_descendants_iterator_smastar,
                         \&AI::Pathfinding::SMAstar::Path::fcost,
			 \&AI::Pathfinding::SMAstar::Path::backup_fvals,
			 $log_function,
			 $str_function,
			 \&AI::Pathfinding::SMAstar::Path::progress,
                         $self->{_show_prog_func},
			 $max_states_in_queue,
                         $max_cost,
	);
}



#################################################################
#
#  SMAstar search
#  Memory-bounded A* search
#