AlphaPADI: Formulaic Alpha Discovery via Pool-Aware Hierarchical Discrete Diffusion
This study addresses the limitations of formulaic alpha discovery, including the neglect of pool context, inadequate preservation of structural hierarchy, and the non-differentiability of pool-level rewards. To overcome these challenges, we propose AlphaPADI, a novel framework that introduces a pool-aware hierarchical discrete diffusion mechanism. By integrating syntax-constrained initialization, multi-scale structural reconstruction, and preference learning, AlphaPADI transcends the bottleneck of conventional item-wise generation, which fails to exploit complementary information within the pool, thereby enabling the efficient synthesis of complementary alpha pools. Empirical evaluations on Chinese and U.S. stock markets demonstrate that the proposed method significantly outperforms baseline approaches in both predictive performance and portfolio returns, validating the effectiveness of pool-aware generation for financial signal discovery.