Having tensors where multiple axes have the same dim tag lead to problems in _get_input_axis_to_returnn as well as when creating out_returnn_axis_to_torch_axis in _base_get_output_shape_from_returnn. Using the new dim tag format stag-single:<idx>:<name> for spatial axes in returnn (see https://github.com/rwth-i6/returnn/pull/490), we can circumvent this.
Having tensors where multiple axes have the same dim tag lead to problems in
_get_input_axis_to_returnnas well as when creatingout_returnn_axis_to_torch_axisin_base_get_output_shape_from_returnn. Using the new dim tag formatstag-single:<idx>:<name>for spatial axes in returnn (see https://github.com/rwth-i6/returnn/pull/490), we can circumvent this.