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HalfBuilder simply calls GrowBuilder or FullBuilder with a certain  
probability.  So the only possible difference would be in your  
parameter settings.  And so it is:

>> gp.koza.half.min-depth = 12
>> gp.koza.half.max-depth = 55
>>
>> gp.koza.grow.min-depth = 5
>> gp.koza.grow.max-depth = 13

55 is a HUGE number, which will generate gigantic trees.  Consider if  
HalfBuilder tries to make a full tree of depth 55 and your trees  
average to binary.  That's O(2^55) nodes. Ordinarily these methods  
have min and max values set somewhere between 2 and 7.  Traditionally  
grow is set to 5 and 5 (for mutation), and half is set to 2 and 6 (for  
initialization).  I wouldn't deviate from that much.

Sean

On Apr 10, 2011, at 9:21 AM, Pawan Kumar wrote:

> same code works fine if I use GrowBuilder, FullBuilder but create  
> problem with HalfBuilder.