Answers.Body: <blockquote>
  <p>If I am correct, the branching factor is the maximum number of successors of any node</p>
  </blockquote>
  <p>You are correct, they should also be the immediate ones:</p>
  <p><a href="https://i.sstatic.net/pdkaG.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/pdkaG.jpg" alt="branching factor" /></a></p>
  <blockquote>
  <p>If 11 is the goal state and I start going backwards, is 10 considered as successor of 5? Even if it do not leads me further to my start state 1?</p>
  </blockquote>
  <p><strong>No, there is also a bit of misunderstanding of bidirectional search:</strong> In bidirectional search you run <strong>2</strong> simultaneous searches, one forward from the initial state, and another one backwards from the goal(hoping they meet in the middle and save you steps), if actions are reversible ( going from node to node), the successor nodes become predecessors in one search and vice versa, and your goal becomes your initial state, in your case:</p>
  <p><a href="https://i.sstatic.net/hdwhY.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/hdwhY.jpg" alt="bidirectional search" /></a></p>
  <h3>Reference/source</h3>
  <p><a href="http://aima.cs.berkeley.edu/" rel="nofollow noreferrer">Artificial Intelligence: A Modern Approach</a>, by S. Russell and P. Norvig.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-01-15T03:26:07.690Z
Answers.LastActivityDate: 2017-01-16T03:59:54.960Z
Answers.LastEditDate: 2020-06-17T09:57:20.710Z
Answers.UserDisplayName: Keno
Body: <p>If I am correct, the branching factor is the maximum number of successors of any node.</p>
  <p>When I am applying bidirectional search to a transition graph like this one below</p>
  <p><a href="https://i.sstatic.net/ZmUoK.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ZmUoK.jpg" alt="enter image description here" /></a></p>
  <p>If 11 is the goal state and I start going backwards, is 10 considered as a successor of 5? Even if it does not leads me further to my start state 1?</p>
  
Tags: <search><branching-factors><bidirectional-search>
Title: Is the 'direction' considered, when determining the branching factor in bidirectional search?
UserDisplayName: Artery
ThreadText: # Is the 'direction' considered, when determining the branching factor in bidirectional search?
  
  (Asked by: username_0 on 2017-01-14)
  
  If I am correct, the branching factor is the maximum number of successors of any node.
  
  When I am applying bidirectional search to a transition graph like this one below
  
  [![enter image description here](https://i.sstatic.net/ZmUoK.jpg)](https://i.sstatic.net/ZmUoK.jpg)
  
  If 11 is the goal state and I start going backwards, is 10 considered as a successor of 5? Even if it does not leads me further to my start state 1?
  
  **Tags:** search, branching-factors, bidirectional-search
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2017-01-15. Score: 4 | Accepted answer
  
  > If I am correct, the branching factor is the maximum number of successors of any node
  
  You are correct, they should also be the immediate ones:
  
  [![branching factor](https://i.sstatic.net/pdkaG.jpg)](https://i.sstatic.net/pdkaG.jpg)
  
  > If 11 is the goal state and I start going backwards, is 10 considered as successor of 5? Even if it do not leads me further to my start state 1?
  
  **No, there is also a bit of misunderstanding of bidirectional search:** In bidirectional search you run **2** simultaneous searches, one forward from the initial state, and another one backwards from the goal(hoping they meet in the middle and save you steps), if actions are reversible ( going from node to node), the successor nodes become predecessors in one search and vice versa, and your goal becomes your initial state, in your case:
  
  [![bidirectional search](https://i.sstatic.net/hdwhY.jpg)](https://i.sstatic.net/hdwhY.jpg)
  
  ### Reference/source
  
  [Artificial Intelligence: A Modern Approach](http://aima.cs.berkeley.edu/), by S. Russell and P. Norvig.
  
  
  ---
  
  