P(Expression|Grammar): Probability of deriving an algebraic expression
with a probabilistic context-free grammar
- URL: http://arxiv.org/abs/2212.00751v2
- Date: Fri, 2 Dec 2022 08:59:59 GMT
- Title: P(Expression|Grammar): Probability of deriving an algebraic expression
with a probabilistic context-free grammar
- Authors: Urh Primo\v{z}i\v{c} and Ljup\v{c}o Todorovski and Matej Petkovi\'c
- Abstract summary: We show that the problem of calculating the probability of deriving a given expression with a given grammar is undecidable in general.
We then present specific grammars for generating linear, rational, and hyperbolic expressions.
For those grammars, we design algorithms for calculating the exact probability and efficient approximation with arbitrary precision.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Probabilistic context-free grammars have a long-term record of use as
generative models in machine learning and symbolic regression. When used for
symbolic regression, they generate algebraic expressions. We define the latter
as equivalence classes of strings derived by grammar and address the problem of
calculating the probability of deriving a given expression with a given
grammar. We show that the problem is undecidable in general. We then present
specific grammars for generating linear, polynomial, and rational expressions,
where algorithms for calculating the probability of a given expression exist.
For those grammars, we design algorithms for calculating the exact probability
and efficient approximation with arbitrary precision.
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