def test_vec2d_add(): node_a = (1, 2) node_b = (2, 3) res_1 = Vec2d.add(node_a, node_b) res_2 = Vec2d.add(node_b, node_a) assert res_1 == res_2 assert res_1 == (3, 5)
def a_star(grid_map: GridTransitionMap, start: IntVector2D, end: IntVector2D, a_star_distance_function: IntVector2DDistance = Vec2d. get_manhattan_distance, avoid_rails=False, respect_transition_validity=True, forbidden_cells: IntVector2DArray = None) -> IntVector2DArray: """ :param avoid_rails: :param grid_map: Grid Map where the path is found in :param start: Start positions as (row,column) :param end: End position as (row,column) :param a_star_distance_function: Define the distance function to use as heuristc: -get_euclidean_distance -get_manhattan_distance -get_chebyshev_distance :param respect_transition_validity: Whether or not a-star respect allowed transitions on the grid map. - True: Respects the validity of transition. This generates valid paths, of no path if it cannot be found - False: This always finds a path, but the path might be illegal and thus needs to be fixed afterwards :param forbidden_cells: List of cells where the path cannot pass through. Used to avoid certain areas of Grid map :return: IF a path is found a ordered list of al cells in path is returned """ """ Returns a list of tuples as a path from the given start to end. If no path is found, returns path to closest point to end. """ rail_shape = grid_map.grid.shape start_node = AStarNode(start, None) end_node = AStarNode(end, None) open_nodes = OrderedSet() closed_nodes = OrderedSet() open_nodes.add(start_node) while len(open_nodes) > 0: # get node with current shortest est. path (lowest f) current_node = None for item in open_nodes: if current_node is None: current_node = item continue if item.f < current_node.f: current_node = item # pop current off open list, add to closed list open_nodes.remove(current_node) closed_nodes.add(current_node) # found the goal if current_node == end_node: path = [] current = current_node while current is not None: path.append(current.pos) current = current.parent # return reversed path return path[::-1] # generate children children = [] if current_node.parent is not None: prev_pos = current_node.parent.pos else: prev_pos = None for new_pos in [(0, -1), (0, 1), (-1, 0), (1, 0)]: # update the "current" pos node_pos: IntVector2D = Vec2d.add(current_node.pos, new_pos) # is node_pos inside the grid? if node_pos[0] >= rail_shape[0] or node_pos[0] < 0 or node_pos[ 1] >= rail_shape[1] or node_pos[1] < 0: continue # validate positions # if not grid_map.validate_new_transition( prev_pos, current_node.pos, node_pos, end_node.pos) and respect_transition_validity: continue # create new node new_node = AStarNode(node_pos, current_node) # Skip paths through forbidden regions if they are provided if forbidden_cells is not None: if node_pos in forbidden_cells and new_node != start_node and new_node != end_node: continue children.append(new_node) # loop through children for child in children: # already in closed list? if child in closed_nodes: continue # create the f, g, and h values child.g = current_node.g + 1.0 # this heuristic avoids diagonal paths if avoid_rails: child.h = a_star_distance_function( child.pos, end_node.pos) + np.clip( grid_map.grid[child.pos], 0, 1) else: child.h = a_star_distance_function(child.pos, end_node.pos) child.f = child.g + child.h # already in the open list? if child in open_nodes: continue # add the child to the open list open_nodes.add(child) # no full path found if len(open_nodes) == 0: return []