Integration with Weights & Biases

First thing first, you need to install wandb with

pip install wandb

Create a free account then run

wandb login

in your terminal. Follow the link to get an API token that you will need to paste, then you’re all set!



 WandbCallback (log:str=None, log_preds:bool=True,
                log_preds_every_epoch:bool=False, log_model:bool=False,
                model_name:str=None, log_dataset:bool=False,
                valid_dl:fastai.data.core.TfmdDL=None, n_preds:int=36,
                seed:int=12345, reorder=True)

Saves model topology, losses & metrics

Type Default Details
log str None What to log (can be gradients, parameters, all or None)
log_preds bool True Whether to log model predictions on a wandb.Table
log_preds_every_epoch bool False Whether to log predictions every epoch or at the end
log_model bool False Whether to save the model checkpoint to a wandb.Artifact
model_name str None The name of the model_name to save, overrides SaveModelCallback
log_dataset bool False Whether to log the dataset to a wandb.Artifact
dataset_name str None A name to log the dataset with
valid_dl TfmdDL None If log_preds=True, then the samples will be drawn from valid_dl
n_preds int 36 How many samples to log predictions
seed int 12345 The seed of the samples drawn
reorder bool True

Optionally logs weights and or gradients depending on log (can be “gradients”, “parameters”, “all” or None), sample predictions if log_preds=True that will come from valid_dl or a random sample of the validation set (determined by seed). n_preds are logged in this case.

If used in combination with SaveModelCallback, the best model is saved as well (can be deactivated with log_model=False).

Datasets can also be tracked:

  • if log_dataset is True, tracked folder is retrieved from learn.dls.path
  • log_dataset can explicitly be set to the folder to track
  • the name of the dataset can explicitly be given through dataset_name, otherwise it is set to the folder name
  • Note: the subfolder “models” is always ignored

For custom scenarios, you can also manually use functions log_dataset and log_model to respectively log your own datasets and models.



 Learner.gather_args ()

Gather config parameters accessible to the learner



 Learner.gather_args ()

Gather config parameters accessible to the learner



 log_dataset (path, name=None, metadata={}, description='raw dataset')

Log dataset folder



 log_model (path, name=None, metadata={}, description='trained model')

Log model file

Example of use:

Once your have defined your Learner, before you call to fit or fit_one_cycle, you need to initialize wandb:

import wandb

To use Weights & Biases without an account, you can call wandb.init(anonymous='allow').

Then you add the callback to your learner or call to fit methods, potentially with SaveModelCallback if you want to save the best model:

from fastai.callback.wandb import *

# To log only during one training phase
learn.fit(..., cbs=WandbCallback())

# To log continuously for all training phases
learn = learner(..., cbs=WandbCallback())

Datasets and models can be tracked through the callback or directly through log_model and log_dataset functions.

For more details, refer to W&B documentation.