eliminate `megatron/model/__init__.py`

[stas00]

megatron/model/__init__.py seem to lead to circular reports quite often, when importing from other megatron libraries, so it's probably the best idea to remove it, rather than continually working around it.

This will require adapting all these to import from the corresponding module each of the imported symbols reside in:

./pretrain_gpt.py:from megatron.model import GPTModel, GPTModelPipe
./megatron/training.py:from megatron.model import Float16Module
./megatron/training.py:from megatron.model import DistributedDataParallel as LocalDDP
./megatron/optimizer/__init__.py:from megatron.model import LayerNorm
./megatron/schedules.py:from megatron.model import DistributedDataParallel as LocalDDP
./megatron/schedules.py:from megatron.model import Float16Module
./megatron/text_generation_utils.py:from megatron.model import DistributedDataParallel as LocalDDP
./megatron/text_generation_utils.py:from megatron.model import Float16Module
./megatron/model/realm_model.py:from megatron.model import BertModel
./megatron/model/transformer.py:from megatron.model import LayerNorm
./megatron/model/bert_model.py:from megatron.model import LayerNorm
./megatron/model/gpt_model.py:from megatron.model import LayerNorm
./tasks/zeroshot_gpt/evaluate.py:from megatron.model import GPTModel
./tasks/zeroshot_gpt/evaluate.py:from megatron.model import DistributedDataParallel as LocalDDP
./tasks/zeroshot_gpt/evaluate.py:from megatron.model import Float16Module
./checkpoint-analysis.ipynb:    "from megatron.model import GPTModel\n",
./pretrain_bert.py:from megatron.model import BertModel
./pretrain_t5.py:from megatron.model import T5Model
./tools/generate_samples_gpt.py:from megatron.model import GPTModel

This is a very basic python task and requires no knowledge of Megatron or Deepspeed.

Steps:

1. git rm megatron/model/__init__.py
2. adapt all the calls listed above
3. run make test to ensure things still work.

Thank you.

[jtboing]

Hello. I would like to take this issue please.

[stas00]

Yes, please and thank you, @jtboing!

[jtboing]

I've made the pull request #117 with the required changes. Please notify me if any further changes are required. Thanks.