Print

Print


yes, there is an upper limit: a depth of 17.  It depends on how you  
are doing breeding.  Under the gp directory, look in the parameter  
files for parameters that have maxdepth.  This parameters controls  
how depth the newly bred trees can be.  Also, look for parameters  
with same containing max-depth, which controls how large the initial  
trees are.

Keith




On Jul 24, 2008, at 5:15 PM, David R White wrote:

> Hi,
>
> Thanks for the reply Shane.  The below is for the initialisation of  
> the population, but I'm actually concerned about how large the  
> trees can become within the run itself.  Is there some upper  
> limit?  Sorry, I don't think I phrased my question very well!
>
> Cheers
>
> David
>
> Shane wrote:
>> Take a look at this in koza.params:
>>
>> # The tree uses an ec.gp.koza.HalfBuilder to create
>> # itself initially.
>> # HalfBuilder will pick GROW half the time and FULL
>> # the other half, with a ramp from 2 to 6 inclusive.
>> # By ramp we mean that it first picks a random number between
>> # 2 and 6 inclusive.  This then becomes the *maximum* tree size
>> # (for the FULL approach, it's the tree size of the tree, for
>> # GROW, the tree can get no bigger than this)
>>
>> gp.tc.0.init = ec.gp.koza.HalfBuilder
>>
>> # We set the default for HalfBuilder to be a ramp of 2--6,
>> # with a grow probability of 0.5
>> gp.koza.half.min-depth = 2
>> gp.koza.half.max-depth = 6
>> gp.koza.half.growp = 0.5
>>
>>
>>
>> On Thu, Jul 24, 2008 at 12:08 PM, David Robert White  
>> <[log in to unmask] <mailto:[log in to unmask]>> wrote:
>>
>>     Hi,
>>
>>     Please could someone help me with this query:
>>
>>     Is there a limit on the tree sizes that ECJ can create?  Is there
>>     any restriction on tree size that I should know about?  I'm  
>> asking
>>     because I am experiencing bloat in a run up to a point, and no
>>     further increase in size after that point.  Perhaps some internal
>>     limit has been reached?
>>
>>     Thanks,
>>
>>     David
>>
>>     --     David R White
>>
>>     Research Student
>>     Department of Computer Science
>>     University of York
>>     York YO10 5DD
>>     United Kingdom
>>
>>
>
> -- 
> David R White
>
> Research Student
> Department of Computer Science
> University of York
> York YO10 5DD
> United Kingdom
>
> Phone: +44 (0)1904 434756