callbacks.rst

Build a Callback

This module houses a collection of callbacks that can be passed into the trainer

from pl_bolts.callbacks import PrintTableMetricsCallback
import pytorch_lightning as pl

trainer = pl.Trainer(callbacks=[PrintTableMetricsCallback()])

# loss│train_loss│val_loss│epoch
# ──────────────────────────────
# 2.2541470527648926│2.2541470527648926│2.2158432006835938│0

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What is a Callback

A callback is a self-contained program that can be intertwined into a training pipeline without polluting the main research logic.

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Create a Callback

Creating a callback is simple:

from pytorch_lightning.callbacks import Callback

class MyCallback(Callback)
    def on_epoch_end(self, trainer, pl_module):
        # do something

Please refer to Callback docs for a full list of the 20+ hooks available.