A* algorithm in AI

The A* (pronounced "A-star") algorithm is a widely used pathfinding and graph traversal algorithm in the field of artificial intelligence and computer science. It is an extension of Dijkstra's algorithm with heuristic evaluation to efficiently find the shortest path between two nodes in a graph.

Here's a high-level overview of how the A* algorithm works:

Initialization:

Create an open list (priority queue) and a closed list (set).
Add the starting node to the open list.
Loop:

While the open list is not empty:
Pop the node with the lowest total cost (f(n)) from the open list. This is the node with the lowest combined cost of the actual cost from the start node (g(n)) and the heuristic cost to the goal node (h(n)).
If the popped node is the goal node, the path has been found.
Otherwise, expand the node by considering all its neighbors.
For each neighbor:
If it is not traversable or is in the closed list, skip it.
If it is not in the open list, calculate its f, g, and h values and add it to the open list.
If it is already in the open list, check if this path to that node is better than the previous one. If so, update its values accordingly.
Termination:

If the open list is empty, the goal node is unreachable, and the search terminates without finding a path.
Path reconstruction:

Once the goal node is reached, the shortest path can be reconstructed by backtracking from the goal node to the start node using the parent pointers stored during the search.
The efficiency of A* heavily depends on the heuristic function used (h(n)), which estimates the cost from the current node to the goal. An admissible heuristic ensures that A* will always find the optimal path if one exists, while an inadmissible heuristic may sacrifice optimality for speed.

Overall, A* is a powerful algorithm that is commonly used in various applications such as robotics, video games, and route planning due to its ability to efficiently find the shortest path while considering both actual costs and heuristic estimates. Follow AlmaBetter for more insights like this and get access to free AI tutorial!