dding3

> In Orca Estimators, we assume `features_cols` is multiple Inputs for model, instead of different columns that could be stacked and serve as one model input. It seems your model...

> Xshards now does not support 1) shuffle dataframe, 2) astype (data type change), 3) train_test_split, 4) duplicate whole dataframe according to one column. I think for `train_test_split`, `astype`, `duplicate`...

Updated the code to change the mllib vectors type to array, I think if it's for change the array type to pytorch tensor type, we may need use `transform_shard` api....

> Add a `transform` function to solve the error. > > ``` > def transform(df): > result = { > "x": np.stack([df['f1'].to_numpy(), ..., df['f8'].to_numpy()], axis=1), > "y": df['label'].to_numpy()} > return...