<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>

CC BY-SA 3.0
2017-01-15T03:26:07.690Z
2017-01-16T03:59:54.960Z
2020-06-17T09:57:20.710Z
Keno
<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>

<search><branching-factors><bidirectional-search>
Is the 'direction' considered, when determining the branching factor in bidirectional search?
Artery
# 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


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## 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.


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