that t-related Lagrange interpolation is
suboptimal for diffusion model and reveal a compact search space comprised of
time steps and solver coefficients. Building on our analysis, we propose a
novel differentiable solver search algorithm to identify more optimal solver.
Equipped with the searched solver, rectified-flow models, e.g., SiT-XL/2 and
FlowDCN-XL/2, achieve FID scores of 2.40 and 2.35, respectively, on ImageNet256
with only 10 steps. Meanwhile, DDPM model, DiT-XL/2, reaches a FID score of
2.33 wi