dataset getitem type

[Abhipray]

The getitem() in feeding.dataset.py returns an array of type np.float32. My data is not in float32 (it's complex). Maybe it's best if we don't typecast.

[ynop]

As far as I see now, only in the MultiFrameDataset, the typecast is forced. Otherwise it depends on the containers/transforms used.

If you mean that one, we could probably change that.