[PyTorch] dyn.strided_slice loses shape information

Questions
2

Yes your observation is correct. We cannot support PT retinanet for two reasons:

  • Our dynamic strided slice doesn’t work great when input shape is partially static/dynamic. It makes output shape dynamic in all dimensions, even if slicing is only in a certain dimension (batch axis etc). Unfortunately this is a limitation of how runtime shapes are represented in Relay: Runtime shapes are fully dynamic in all dimensions.

  • Our split op doesn’t support dynamic sections. This is the error you got. Even if the first point cannot be overcome, in principle we can support retinanet if our split op supports dynamic sections (although performance would be suboptimal than the ideal case). This would be an easier solution in the short term.