Order-Preserving GFlowNets
- URL: http://arxiv.org/abs/2310.00386v2
- Date: Sun, 25 Feb 2024 16:02:56 GMT
- Title: Order-Preserving GFlowNets
- Authors: Yihang Chen, Lukas Mauch
- Abstract summary: Generative Flow Networks (GFlowNets) have been introduced as a method to sample a diverse set of candidates with probabilities proportional to a given reward.
OP-GFNs sample with probabilities in proportion to a learned reward function consistent with a provided (partial) order on the candidates.
We demonstrate OP-GFN's state-of-the-art performance in single-objective and multi-objective datasets.
- Score: 0.9532413070964598
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Generative Flow Networks (GFlowNets) have been introduced as a method to
sample a diverse set of candidates with probabilities proportional to a given
reward. However, GFlowNets can only be used with a predefined scalar reward,
which can be either computationally expensive or not directly accessible, in
the case of multi-objective optimization (MOO) tasks for example. Moreover, to
prioritize identifying high-reward candidates, the conventional practice is to
raise the reward to a higher exponent, the optimal choice of which may vary
across different environments. To address these issues, we propose
Order-Preserving GFlowNets (OP-GFNs), which sample with probabilities in
proportion to a learned reward function that is consistent with a provided
(partial) order on the candidates, thus eliminating the need for an explicit
formulation of the reward function. We theoretically prove that the training
process of OP-GFNs gradually sparsifies the learned reward landscape in
single-objective maximization tasks. The sparsification concentrates on
candidates of a higher hierarchy in the ordering, ensuring exploration at the
beginning and exploitation towards the end of the training. We demonstrate
OP-GFN's state-of-the-art performance in single-objective maximization (totally
ordered) and multi-objective Pareto front approximation (partially ordered)
tasks, including synthetic datasets, molecule generation, and neural
architecture search.
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