Selection of function symbols from the grammar is biased
|Reported by:||gkronber||Owned by:||gkronber|
Description (last modified by gkronber)
Steps to reproduce:
- Create symbolic regression problem
- Also activate "Special Functions" group in the grammar
- Start a run
Expected: distribution of function symbols in the initial population should be nearly uniform. Actual: Symbols from the "Arithmetic Functions" group are much more likely then symbols from the "Special Functions" group.
As explained in the comments below the likely reason for this is that the tree creator (PTC2) introduces a bias against unary functions because it must also produce larger trees.
Change History (4)
Changed 2 years ago by mkommend
comment:2 Changed 2 years ago by gkronber
- Description modified (diff)
- Summary changed from Selection of function symbols from the grammar prefers symbols from smaller groups to Selection of function symbols from the grammar is biased