🤖 AI Summary
Conventional unbalanced optimal transport (UOT) in heterogeneous spaces suffers from fixed, pre-specified ground cost functions that fail to capture intrinsic geometric structures of data. Method: We propose a cost-regularized unbalanced Gromov–Wasserstein (NR-UGW) framework that jointly optimizes the transport plan and a learnable ground cost function. The cost is parameterized via linear transformations within an inner-product family and integrated with entropic regularization for computational efficiency. NR-UGW supports mass creation/destruction and structural alignment across Euclidean spaces. Contribution/Results: Unlike standard UOT, NR-UGW dynamically adapts to geometric discrepancies between heterogeneous measures. On single-cell multi-omics data, it significantly improves contour alignment accuracy under sample-missing conditions—particularly where cell-level correspondences are absent—enabling robust cross-modal integration without explicit matching.
📝 Abstract
Unbalanced optimal transport (UOT) provides a flexible way to match or compare nonnegative finite Radon measures. However, UOT requires a predefined ground transport cost, which may misrepresent the data's underlying geometry. Choosing such a cost is particularly challenging when datasets live in heterogeneous spaces, often motivating practitioners to adopt Gromov-Wasserstein formulations. To address this challenge, we introduce cost-regularized unbalanced optimal transport (CR-UOT), a framework that allows the ground cost to vary while allowing mass creation and removal. We show that CR-UOT incorporates unbalanced Gromov-Wasserstein type problems through families of inner-product costs parameterized by linear transformations, enabling the matching of measures or point clouds across Euclidean spaces. We develop algorithms for such CR-UOT problems using entropic regularization and demonstrate that this approach improves the alignment of heterogeneous single-cell omics profiles, especially when many cells lack direct matches.