n = torch.arange(N, device=X.device)[:, None, None, None]
t = torch.arange(t0, t1, device=X.device)[None, None, :, None]
dv = torch.arange(DV, device=X.device)[None, None, None, :]
n = torch.arange(N, device=X.device)[:, None, None, None]
t = torch.arange(t0, t1, device=X.device)[None, None, :, None]
dv = torch.arange(DV, device=X.device)[None, None, None, :]