Riemannian Variational Flow Matching for Material and Protein Design
Olga Zaghen, Floor Eijkelboom, Alison Pouplin, Cong Liu, Max Welling, Jan-Willem van de Meent, Erik J. Bekkers
TL;DR
This work introduces Riemannian Gaussian Variational Flow Matching (RG-VFM), a geometric extension of variational flow matching for data on manifolds that uses a Riemannian Gaussian posterior to model endpoint distributions. By analyzing Jacobi fields, the authors show that RG-VFM captures curvature information via the endpoint distance $\|\log_{x_1}(\mu_t^{\theta}(x))\|^2$ and differs from Riemannian Flow Matching (RFM) by a curvature-dependent term, with Euclidean space recovering the standard VFM/CFM equivalence. The paper proves that RG-VFM reduces to the Fréchet mean under suitable assumptions and demonstrates, through synthetic curved spaces and real-world MOF and protein design tasks, that endpoint-based variational training yields sharper distributions and better geometry alignment than velocity-based methods. Empirical results on MOFFlow and protein backbone generation show consistent improvements in structure prediction, designability, and RMSD metrics, validating the practical value of incorporating curvature-aware variational objectives into manifold-valued generative modeling. Overall, RG-VFM offers a principled, geometry-respecting, and computationally efficient approach for learning probability paths on complex geometries with broad applicability in materials and biomolecular design.
Abstract
We present Riemannian Gaussian Variational Flow Matching (RG-VFM), a geometric extension of Variational Flow Matching (VFM) for generative modeling on manifolds. In Euclidean space, predicting endpoints (VFM), velocities (FM), or noise (diffusion) are largely equivalent due to affine interpolations. On curved manifolds this equivalence breaks down, and we hypothesize that endpoint prediction provides a stronger learning signal by directly minimizing geodesic distances. Building on this insight, we derive a variational flow matching objective based on Riemannian Gaussian distributions, applicable to manifolds with closed-form geodesics. We formally analyze its relationship to Riemannian Flow Matching (RFM), exposing that the RFM objective lacks a curvature-dependent penalty - encoded via Jacobi fields - that is naturally present in RG-VFM. Experiments on synthetic spherical and hyperbolic benchmarks, as well as real-world tasks in material and protein generation, demonstrate that RG-VFM more effectively captures manifold structure and improves downstream performance over Euclidean and velocity-based baselines.
