lightning/docs/source-fabric/api/utilities.rst

70 lines
1.7 KiB
ReStructuredText

################
Fabric Utilities
################
seed_everything
===============
This function sets the random seed in important libraries.
In a single line of code, you can seed PyTorch, NumPy, and Python:
.. code-block:: diff
+ from lightning.fabric import seed_everything
seed = 42
- random.seed(seed)
- numpy.random.seed(seed)
- torch.manual_seed(seed)
- torch.cuda.manual_seed(seed)
+ seed_everything(seed)
The same is also available as a method on the Fabric object if you don't want to import it separately:
.. code-block:: python
from lightning.fabric import Fabric
fabric.Fabric()
fabric.seed_everything(42)
In distributed settings, you may need to set a different seed per process, depending on the application.
For example, when generating noise or data augmentations. This is very straightforward:
.. code-block:: python
fabric = Fabric(...)
fabric.seed_everything(seed + fabric.global_rank)
By default, ``seed_everything`` also handles the initialization of the seed in :class:`~torch.utils.data.DataLoader` worker processes:
.. code-block:: python
fabric = Fabric(...)
# By default, we handle DataLoader workers too:
fabric.seed_everything(..., workers=True)
# Can be turned off:
fabric.seed_everything(..., workers=False)
----
print
=====
Avoid duplicated print statements in the logs in distributed training by using Fabric's :meth:`~lightning.fabric.fabric.Fabric.print` method:
.. code-block:: python
print("This message gets printed in every process. That's a bit messy!")
fabric = Fabric(...)
fabric.print("This message gets printed only in the main process. Much cleaner!")