Classifier-Free Guidance: From High-Dimensional Analysis to Generalized Guidance Forms
- URL: http://arxiv.org/abs/2502.07849v2
- Date: Thu, 22 May 2025 14:59:12 GMT
- Title: Classifier-Free Guidance: From High-Dimensional Analysis to Generalized Guidance Forms
- Authors: Krunoslav Lehman Pavasovic, Jakob Verbeek, Giulio Biroli, Marc Mezard,
- Abstract summary: We show that CFG accurately reproduces the target distribution in sufficiently high and infinite dimensions.<n>We show that there is a large family of guidances enjoying this property, in particular nonlinear CFG generalizations.<n>Our findings are validated with experiments on class-conditional and text-to-image generation using state-of-the-art diffusion and flow-matching models.
- Score: 22.44946627454133
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Classifier-Free Guidance (CFG) is a widely adopted technique in diffusion and flow-based generative models, enabling high-quality conditional generation. A key theoretical challenge is characterizing the distribution induced by CFG, particularly in high-dimensional settings relevant to real-world data. Previous works have shown that CFG modifies the target distribution, steering it towards a distribution sharper than the target one, more shifted towards the boundary of the class. In this work, we provide a high-dimensional analysis of CFG, showing that these distortions vanish as the data dimension grows. We present a blessing-of-dimensionality result demonstrating that in sufficiently high and infinite dimensions, CFG accurately reproduces the target distribution. Using our high-dimensional theory, we show that there is a large family of guidances enjoying this property, in particular non-linear CFG generalizations. We study a simple non-linear power-law version, for which we demonstrate improved robustness, sample fidelity and diversity. Our findings are validated with experiments on class-conditional and text-to-image generation using state-of-the-art diffusion and flow-matching models.
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