Dear RDKitters,

I'm in the process of training a 3-class decision tree model. I have 
roughly about 1500 compounds with an almost equal distribution of the 3 
classes.

This is the Grow command I'm using for MorganFP model:
nPossible = [0]+[2]*2048+[3]
cmp.Grow(pts,attrs=[1],nPossibleVals=[3],nTries=10,buildDriver=CrossValidate.CrossValidationDriver,treeBuilder=SigTreeBuilder,needsQuantization=False,maxDepth=3)

and these are code lines using a descriptor based model:
ndescrs = len(pts[0])-2
boundsPerVar = [0]+[1]*ndescrs+[0]
nPossible = [0]+[2]*ndescrs+[3]
attrs = range(1,ndescrs+1)
cmp.Grow(pts,attrs=attrs,nPossibleVals=nPossible,nTries=10,buildDriver=CrossValidate.CrossValidationDriver,treeBuilder=QuantTreeBoot,
 
needsQuantization=False,nQuantBounds=boundsPerVar, maxDepth=3)


Apparently, I screwed up parts of my code, because the "Cycle output" is 
the following:
Cycle:    0
Cycle:    3
Cycle:    6
Cycle:    9
Cycle:   12
Cycle:   15
Cycle:   18
Cycle:   21
Cycle:   24
Cycle:   27


Up to yesterday, the numbering scheme was 0,1,2 -- however, this effect 
not really worries me. Or is it somethin to take care of?

I played around with the following settings:
* random training / test set selection (training set size: 75 %)
* diverse selection of training / test set (training set size: 75 %)
* MorganFP as well as RDKit descriptors - either a random selection of the 
training set or a diverse selection
* nTries = 10 or 20 or 30


In all cases, the statistics is really bad: about 50 percent are 
misclassified, e.g.:
"
        *** Vote Results ***
misclassified: 580/1180 (%49.15)        580/1180 (%49.15)

average correct confidence:    0.7837
average incorrect confidence:  0.7528
"

Interestingly, there is a really small difference between the average 
confidence level for the correct as well as the incorrect classifications. 
As far as I got it this tells me that the model is really bad - an 
information I already got by the vote results themselves.


Which parameters are worthhile to test?


Cheers & Thanks,
Paul


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