A star algorithm in artificial intelligence
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The document provides an overview of the A* search algorithm, a widely used best-first search technique that finds the shortest path in a search space by utilizing a heuristic function h(n) and path cost g(n). It outlines the steps involved in the algorithm, including placing the starting node on an open list, evaluating nodes, and expanding successors until the goal node is found. Additionally, an example is given to illustrate the application of the algorithm, indicating that the optimal path found has a cost of 6.
A star algorithm in artificial intelligence
- 1. Artificial Intelligence Tutorial A* Search Algorithm Our website:- pywix.blogspot.com Rahul Gupta Sir Video By Digital Classes
- 2. Introduction • A* search is the most commonly known form of best-first search. It uses heuristic function h(n), and cost to reach the node n from the start state g(n). • A* search algorithm finds the shortest path through the search space using the heuristic function. • This search algorithm expands less search tree and provides optimal result faster. it uses g(n)+h(n) Our website:- pywix.blogspot.com Rahul Gupta Sir Video by Digital classes
- 3. Introduction Our website:- pywix.blogspot.com Rahul Gupta Sir Video by Digital classes
- 4. Algorithm • Algorithm of A* search: • Step1: Place the starting node in the OPEN list. • Step 2: Check if the OPEN list is empty or not, if the list is empty then return failure and stops. • Step 3: Select the node from the OPEN list which has the smallest value of evaluation function (g+h), if node n is goal node then return success and stop, otherwise • Step 4: Expand node n and generate all of its successors, and put n into the closed list. For each successor n', check whether n' is already in the OPEN or CLOSED list, if not then compute evaluation function for n' and place into Open list. • Step 5: Else if node n' is already in OPEN and CLOSED, then it should be attached to the back pointer which reflects the lowest g(n') value. • Step 6: Return to Step 2. Our website:- pywix.blogspot.com Rahul Gupta Sir Video by Digital classes
- 5. Example: • {(S, 5)} • {(S--> A, 4), (S-->G, 10)} • {(S--> A-->C, 4), (S--> A-->B, 7), (S-->G, 10)} • {(S--> A-->C--->G, 6), (S--> A-->C--->D, 11), (S--> A-->B, 7), (S-->G, 10)} • as S--->A--->C--->G it provides the optimal path with cost 6. Our website:- pywix.blogspot.com Rahul Gupta Sir Video by Digital classes
- 6. Our website:- pywix.blogspot.com Rahul Gupta Sir Video by Digital classes