lightning/docs/source/test_set.rst

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.. _test_set:
Test set
========
Lightning forces the user to run the test set separately to make sure it isn't evaluated by mistake.
Testing is performed using the ``trainer`` object's ``.test()`` method.
.. automethod:: pytorch_lightning.trainer.Trainer.test
:noindex:
----------
Test after fit
--------------
To run the test set after training completes, use this method.
.. code-block:: python
# run full training
trainer.fit(model)
# (1) load the best checkpoint automatically (lightning tracks this for you)
trainer.test()
# (2) don't load a checkpoint, instead use the model with the latest weights
trainer.test(ckpt_path=None)
# (3) test using a specific checkpoint
trainer.test(ckpt_path='/path/to/my_checkpoint.ckpt')
# (4) test with an explicit model (will use this model and not load a checkpoint)
trainer.test(model)
----------
Test multiple models
--------------------
You can run the test set on multiple models using the same trainer instance.
.. code-block:: python
model1 = LitModel()
model2 = GANModel()
trainer = Trainer()
trainer.test(model1)
trainer.test(model2)
----------
Test pre-trained model
----------------------
To run the test set on a pre-trained model, use this method.
.. code-block:: python
model = MyLightningModule.load_from_checkpoint(
checkpoint_path='/path/to/pytorch_checkpoint.ckpt',
hparams_file='/path/to/test_tube/experiment/version/hparams.yaml',
map_location=None
)
# init trainer with whatever options
trainer = Trainer(...)
# test (pass in the model)
trainer.test(model)
In this case, the options you pass to trainer will be used when
running the test set (ie: 16-bit, dp, ddp, etc...)
----------
Test with additional data loaders
---------------------------------
You can still run inference on a test set even if the `test_dataloader` method hasn't been
defined within your :ref:`lightning_module` instance. This would be the case when your test data
is not available at the time your model was declared.
.. code-block:: python
# setup your data loader
test = DataLoader(...)
# test (pass in the loader)
trainer.test(test_dataloaders=test)
You can either pass in a single dataloader or a list of them. This optional named
parameter can be used in conjunction with any of the above use cases. Additionally,
you can also pass in an :ref:`datamodules` that have overridden the
:ref:`datamodule-test-dataloader-label` method.
.. code-block:: python
class MyDataModule(pl.LightningDataModule):
...
def test_dataloader(self):
return DataLoader(...)
# setup your datamodule
dm = MyDataModule(...)
# test (pass in datamodule)
trainer.test(datamodule=dm)