Summary:
Pull Request resolved: facebookresearch#461

I was frustrated by the fact that I needed to change the code for every model if I needed to be able to attach heads to it - something we need to do with most trained models.
Ideally, users should be able to write their models without writing anything classy vision specific and be able to attach heads.

I've made a couple of diffs which get us there, wanted to see what everyone thought about them. Please look at the second diff to see the end result.

In this diff, I make the following changes -
- `build_attachable_block` becomes a private function (`_build_attachable_block`), and models  don't need to call it anymore.
- Instead, when someone tries to attach to a module called `my_block`, we recursively search for it and wrap it by a `ClassyBlock` on the fly
- Updated `get_classy_state` and `set_classy_state` to be compatible with the changes
- Users can attach heads to any block which has a unique name (like `block3-2`)
- `models_classy_model_test` wasn't being run internally; renamed
`classy_block_test` to `models_classy_block_test`
- Added additional test cases to test the changes

NOTE: This breaks all checkpoints since the model definitions have changed.

Differential Revision: D20714865

fbshipit-source-id: 95c1ce4655663538919ca28f77f554ea67570edb

Summary:
Pull Request resolved: facebookresearch#461

I was frustrated by the fact that I needed to change the code for every model if I needed to be able to attach heads to it - something we need to do with most trained models.
Ideally, users should be able to write their models without writing anything classy vision specific and be able to attach heads.

I've made a couple of diffs which get us there, wanted to see what everyone thought about them. Please look at the second diff to see the end result.

In this diff, I make the following changes -
- `build_attachable_block` becomes a private function (`_build_attachable_block`), and models  don't need to call it anymore.
- Removed `_should_cache_output` and `set_cache_output` from `ClassyBlock`
- Added a redundant `_attachable_block_names` attribute - this is needed for reading the block names inside torch script (`_attachable_blocks` is inaccessible) - T64918869
- Instead, when someone tries to attach to a module called `my_block`, we recursively search for it and wrap it by a `ClassyBlock` on the fly
- Updated `get_classy_state` and `set_classy_state` to be compatible with the changes
- Users can attach heads to any block which has a unique name (like `block3-2`)
- `models_classy_model_test` wasn't being run internally; renamed
`classy_block_test` to `models_classy_block_test`
- Added additional test cases to test the changes

NOTE: This breaks all checkpoints since the model definitions have changed. We still handle old checkpoints for `ResNeXt` models to allow for a smoother transition -  T61141249

Differential Revision: D20714865

fbshipit-source-id: f48e768aede1c10d25754f0fad0f24ccac9a1503

Summary:
Pull Request resolved: facebookresearch#461

I was frustrated by the fact that I needed to change the code for every model if I needed to be able to attach heads to it - something we need to do with most trained models.
Ideally, users should be able to write their models without writing anything classy vision specific and be able to attach heads.

I've made a couple of diffs which get us there, wanted to see what everyone thought about them. Please look at the second diff to see the end result.

In this diff, I make the following changes -
- `build_attachable_block` becomes a private function (`_build_attachable_block`), and models  don't need to call it anymore.
- Removed `_should_cache_output` and `set_cache_output` from `ClassyBlock`
- Added a redundant `_attachable_block_names` attribute - this is needed for reading the block names inside torch script (`_attachable_blocks` is inaccessible) - T64918869
- Instead, when someone tries to attach to a module called `my_block`, we recursively search for it and wrap it by a `ClassyBlock` on the fly
- Updated `get_classy_state` and `set_classy_state` to be compatible with the changes
- Users can attach heads to any block which has a unique name (like `block3-2`)
- `models_classy_model_test` wasn't being run internally; renamed
`classy_block_test` to `models_classy_block_test`
- Added additional test cases to test the changes

NOTE: This breaks all checkpoints since the model definitions have changed. We still handle old checkpoints for `ResNeXt` models to allow for a smoother transition -  T61141249

Reviewed By: vreis

Differential Revision: D20714865

fbshipit-source-id: 993a841b7190d5fabd751d8cca25381dcd93d898

Summary:
Pull Request resolved: #461

I was frustrated by the fact that I needed to change the code for every model if I needed to be able to attach heads to it - something we need to do with most trained models.
Ideally, users should be able to write their models without writing anything classy vision specific and be able to attach heads.

I've made a couple of diffs which get us there, wanted to see what everyone thought about them. Please look at the second diff to see the end result.

In this diff, I make the following changes -
- `build_attachable_block` becomes a private function (`_build_attachable_block`), and models  don't need to call it anymore.
- Removed `_should_cache_output` and `set_cache_output` from `ClassyBlock`
- Added a redundant `_attachable_block_names` attribute - this is needed for reading the block names inside torch script (`_attachable_blocks` is inaccessible) - T64918869
- Instead, when someone tries to attach to a module called `my_block`, we recursively search for it and wrap it by a `ClassyBlock` on the fly
- Updated `get_classy_state` and `set_classy_state` to be compatible with the changes
- Users can attach heads to any block which has a unique name (like `block3-2`)
- `models_classy_model_test` wasn't being run internally; renamed
`classy_block_test` to `models_classy_block_test`
- Added additional test cases to test the changes

NOTE: This breaks all checkpoints since the model definitions have changed. We still handle old checkpoints for `ResNeXt` models to allow for a smoother transition -  T61141249

Reviewed By: vreis

Differential Revision: D20714865

fbshipit-source-id: f8fa269b5deddbdd77461047850e7050b1bc921a