Hey Uday,

I'm trying to get the SizeFairCrossoverPipeline into my BreedingPipeline, but seems that I'm missing an argument or so. I'm getting this error stack:

Initializing Generation 0
Exception in thread "main" ec.util.ParamClassLoadException: 
No class name provided.
PARAMETER: pop.subpop.0.species.pipe.source.0.source.0
     ALSO: gp.breed.size-fair.source.0
	at ec.util.ParameterDatabase.getInstanceForParameter(
	at ec.BreedingPipeline.setup(
	at ec.BreedingPipeline.setup(
	at ec.breed.MultiBreedingPipeline.setup(
	at ec.Species.setup(
	at ec.Subpopulation.setup(
	at ec.Population.setup(
	at ec.simple.SimpleInitializer.setupPopulation(
	at ec.simple.SimpleInitializer.initialPopulation(
	at ec.simple.SimpleEvolutionState.startFresh(
	at ec.Evolve.main(

while using these parameters for breeding pipeline:

op.subpop.0.species.pipe = ec.breed.MultiBreedingPipeline
# Koza's decision here was odd...
pop.subpop.0.species.pipe.generate-max = false
# Subsidiary pipelines:
pop.subpop.0.species.pipe.num-sources = 2
pop.subpop.0.species.pipe.source.0 =
pop.subpop.0.species.pipe.source.0.prob = 0.9
pop.subpop.0.species.pipe.source.1 = ec.breed.ReproductionPipeline
pop.subpop.0.species.pipe.source.1.prob = 0.1

Simply changed the CrossoverPipeline to SizeFairCrossoverPipeline in the koza.params which I'm using as parent params-file. Could you please also explain
how do you managed to get a variable amount of conditions for your rule-tree? Or does every rule has the same amount of conditions? 
Currently I'm using 5 different tree constraints where each tree represent a rule with a different amount of children. (I don't know set this to random, 
maybe if I know more about the evolution process in detail, but I don't know where I could find such an information)

Greetings from Germany


----- Urspr√ľngliche Mail -----
Von: "Uday kamath" <[log in to unmask]>
An: [log in to unmask]
Gesendet: Freitag, 26. April 2013 01:14:26
Betreff: Re: AW: Re: Postprocessing in


Some of the measures i have in my Rules generation are 
1. Use Homologous Crossover instead of Standard Subtree Crossover, works very effectively in reducing the size or 'bloat' of trees. ECJ now has the Homologous or SizeFair crossover. 
2. As sean mentioned, i have mutation operator that "removes" the subtree in the pipeline. Only thing is if the fitness is not changed or below an epsilon, i accept it. ECJ has bunch of delete or raise mutation for GP trees. 
3. In my final interpreter i have a Simplifier for Boolean Expression, which does logical reduction based on karnaugh maps. 

With these three mechanism i was able to get meaningful and pruned Rules. 
Hope that helps 

On Thu, Apr 25, 2013 at 6:58 PM, Sean Luke < [log in to unmask] > wrote: 

Pruning will be up to you. But you have two ways you can hook into ECJ to do it. 

1. You can create a BreedingPipeline which prunes the trees handed it by its children. This is essentially a mutation mechanism during breeding of individuals. You'd probably set this up as the top-level pipeline, with the standard Koza pipeline structure underneath it, so it's the last thing that operates on new individuals. 

2. Perhaps a better approach would be simply to prune the individual during fitness evaluation prior to testing it. 


Begin forwarded message: 

> From: Bojan Janisch < [log in to unmask] > 
> Date: April 25, 2013 5:27:32 PM EDT 
> To: [log in to unmask] 
> Subject: AW: Re: Postprocessing in 
> Reply-To: ECJ Evolutionary Computation Toolkit < [log in to unmask] > 

> Hi Uday, 
> I already have a plan how the represented rule should be evaluated. I'll write an 
> API to JBoss Drools, which is a rule-based System. The Output of the System will 
> be compared to a goldstandard by a comparator which I have to write. It returns a 
> F-Score or something similar to it. The Score goes into the fitness function. 
> But my problem is the pruning. I need a step where I can check a syntax tree for useless 
> part-trees. Otherwise the trees have no limits on how big it can grow. I wanted to check 
> while post-processing the tree, but seems that ECJ does not support it. 
> How did you solve the chunk-condition problem for rules? 
> Greetings 
> Bojan 
> ----- Urspr√ľngliche Mail ----- 
> Von: Uday kamath < [log in to unmask] > 
> An: [log in to unmask] 
> Gesendet: Thu, 25 Apr 2013 17:28:38 +0200 (CEST) 
> Betreff: Re: Postprocessing in 
> Bojan 
> There are no pre written post processing out of the box as it depends on 
> the problem (function set of GP). I will give a short background which you 
> may find useful for what you are doing. 
> For generating automated Rules to discriminate certain patterns, i had my 
> GP have basic terminals and non-terminals required for the Rule. I would 
> collect my "exceptional" Rules as a memory pad outside of evolutionary 
> runs, everytime i see some well performing ones. Finally i get a Rule set 
> and wrote my Custom "interpreter" that can parse the GP Individuals as 
> s-expression to evaluate. So ECJ gives you GP and Evolution for free, you 
> need to write custom functions and interpreter for them. 
> Hope that helps 
> Uday 
> On Thu, Apr 25, 2013 at 10:29 AM, Bojan Janisch < 
> [log in to unmask] > wrote: 
>> Hello everyone, 
>> is there a post-processing-step in the Genetic Programming algorithm? I've 
>> search through the manual, 
>> but did not find an explanation about this topic. 
>> Thank you and greetings, 
>> Bojan