Add einops to requirements.txt

[ezyang]

This is required by the new VLM code:

[rank0]:Traceback (most recent call last):
[rank0]:  File "/home/ezyang/.local/share/uv/python/cpython-3.10.18-linux-x86_64-gnu/lib/python3.10/runpy.py", line 187, in _run_module_as_main
[rank0]:    mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
[rank0]:  File "/home/ezyang/.local/share/uv/python/cpython-3.10.18-linux-x86_64-gnu/lib/python3.10/runpy.py", line 110, in _get_module_details
[rank0]:    __import__(pkg_name)
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/__init__.py", line 12, in <module>
[rank0]:    import torchtitan.experiments  # noqa: F401
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/experiments/__init__.py", line 10, in <module>
[rank0]:    import torchtitan.experiments.vlm  # noqa: F401
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/experiments/vlm/__init__.py", line 17, in <module>
[rank0]:    from .datasets.mm_datasets import build_mm_dataloader
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/experiments/vlm/datasets/mm_datasets.py", line 29, in <module>
[rank0]:    from .mm_collator_nld import MultiModalCollatorNLD
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/experiments/vlm/datasets/mm_collator_nld.py", line 17, in <module>
[rank0]:    from .utils.image import (
[rank0]:  File "/data/users/ezyang/b/torchtitan/torchtitan/experiments/vlm/datasets/utils/image.py", line 12, in <module>
[rank0]:    import einops as E
[rank0]:ModuleNotFoundError: No module named 'einops'

Signed-off-by: Edward Z. Yang ezyang@meta.com

[ezyang]

Stack from ghstack (oldest at bottom):

• -> Add einops to requirements.txt #1734

[wwwjn]

For models under experiment folder, we have their own requirements (eg, for VLM it's here: https://github.com/pytorch/torchtitan/blob/refs/heads/main/torchtitan/experiments/vlm/requirements.txt). We don't want model dependency under experiment folder to be part of main requirement.txt, which might broke main branch development

[ruisizhang123]

FYI, I tried to run expertments/simple_fsdp and hit missing package error for PIL in experiment/vlm here. However, PIL (Pillow) pkg is missing in VLM's requirements.txt

[tianyu-l]

@wwwjn @fegin as we have more and more experiments, we probably shouldn't import everything, or register all TrainSpec. We may need to optionally do importlib.importmodule like this https://github.com/pytorch/torchtitan/blob/main/torchtitan/train.py#L80

But we need to make sure it works with existing JobConfig extension, which also uses this field.

We may have to extend config/manager.py to handle TrainSpec registration.

[tianyu-l]

closing as this is fixed in #1740