@king_wang pls trace back the error popping up in your piece of code. size mismatch, m1:[1 x 2], m2: [3 x 2] is very clear that the dimensionality does not match. Note that model = RBF(3,2,1) means the dimensionality of input feature should be 3 while your script torch.Tensor([3,2]) just alloc a tensor [3,2].