Allow user to disable the automatic formatting of checkpoint file names.

CHANGELOG.md

@@ -24,6 +24,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added `LightningEnvironment` for Lightning-specific DDP ([#5915](https://github.com/PyTorchLightning/pytorch-lightning/pull/5915))
 
 
+- Added `auto_insert_metric_name` parameter to `ModelCheckpoint` ([#6277](https://github.com/PyTorchLightning/pytorch-lightning/pull/6277))
+
+
 - Added arg to `self.log` that enables users to give custom names when dealing with multiple dataloaders ([#6274](https://github.com/PyTorchLightning/pytorch-lightning/pull/6274))
 
 

pytorch_lightning/callbacks/model_checkpoint.py

@@ -131,6 +131,16 @@ class ModelCheckpoint(Callback):
         ...     filename='sample-mnist-{epoch:02d}-{val_loss:.2f}'
         ... )
 
+        # save epoch and val_loss in name, but specify the formatting yourself (e.g. to avoid problems with Tensorboard
+        # or Neptune, due to the presence of characters like '=' or '/')
+        # saves a file like: my/path/sample-mnist-epoch02-val_loss0.32.ckpt
+        >>> checkpoint_callback = ModelCheckpoint(
+        ...     monitor='val/loss',
+        ...     dirpath='my/path/',
+        ...     filename='sample-mnist-epoch{epoch:02d}-val_loss{val/loss:.2f}',
+        ...     auto_insert_metric_name=False
+        ... )
+
         # retrieve the best checkpoint after training
         checkpoint_callback = ModelCheckpoint(dirpath='my/path/')
         trainer = Trainer(callbacks=[checkpoint_callback])
@@ -156,6 +166,7 @@ def __init__(
         save_weights_only: bool = False,
         mode: str = "min",
         period: int = 1,
+        auto_insert_metric_name: bool = True
     ):
         super().__init__()
         self.monitor = monitor
@@ -164,6 +175,7 @@ def __init__(
         self.save_top_k = save_top_k
         self.save_weights_only = save_weights_only
         self.period = period
+        self.auto_insert_metric_name = auto_insert_metric_name
         self._last_global_step_saved = -1
         self.current_score = None
         self.best_k_models = {}
@@ -356,6 +368,7 @@ def _format_checkpoint_name(
         step: int,
         metrics: Dict[str, Any],
         prefix: str = "",
+        auto_insert_metric_name: bool = True
     ) -> str:
         if not filename:
             # filename is not set, use default name
@@ -367,7 +380,10 @@ def _format_checkpoint_name(
             metrics.update({"epoch": epoch, 'step': step})
             for group in groups:
                 name = group[1:]
-                filename = filename.replace(group, name + "={" + name)
+
+                if auto_insert_metric_name:
+                    filename = filename.replace(group, name + "={" + name)
+
                 if name not in metrics:
                     metrics[name] = 0
             filename = filename.format(**metrics)
@@ -392,6 +408,11 @@ def format_checkpoint_name(self, epoch: int, step: int, metrics: Dict[str, Any],
             >>> ckpt = ModelCheckpoint(dirpath=tmpdir, filename='{epoch}-{val_loss:.2f}')
             >>> os.path.basename(ckpt.format_checkpoint_name(2, 3, metrics=dict(val_loss=0.123456)))
             'epoch=2-val_loss=0.12.ckpt'
+            >>> ckpt = ModelCheckpoint(dirpath=tmpdir,
+            ... filename='epoch={epoch}-validation_loss={val_loss:.2f}',
+            ... auto_insert_metric_name=False)
+            >>> os.path.basename(ckpt.format_checkpoint_name(2, 3, metrics=dict(val_loss=0.123456)))
+            'epoch=2-validation_loss=0.12.ckpt'
             >>> ckpt = ModelCheckpoint(dirpath=tmpdir, filename='{missing:d}')
             >>> os.path.basename(ckpt.format_checkpoint_name(0, 4, metrics={}))
             'missing=0.ckpt'
@@ -400,7 +421,13 @@ def format_checkpoint_name(self, epoch: int, step: int, metrics: Dict[str, Any],
             'step=0.ckpt'
 
         """
-        filename = self._format_checkpoint_name(self.filename, epoch, step, metrics)
+        filename = self._format_checkpoint_name(
+            self.filename,
+            epoch,
+            step,
+            metrics,
+            auto_insert_metric_name=self.auto_insert_metric_name)
+
         if ver is not None:
             filename = self.CHECKPOINT_JOIN_CHAR.join((filename, f"v{ver}"))
 

tests/checkpointing/test_model_checkpoint.py

@@ -425,6 +425,15 @@ def test_model_checkpoint_format_checkpoint_name(tmpdir):
     ckpt_name = ckpt.format_checkpoint_name(4, 3, {'val/loss': 0.03})
     assert ckpt_name == 'epoch=4_val/loss=0.03000.ckpt'
 
+    # auto_insert_metric_name=False
+    ckpt_name = ModelCheckpoint._format_checkpoint_name(
+        'epoch={epoch:03d}-val_acc={val/acc}',
+        3,
+        2,
+        {'val/acc': 0.03},
+        auto_insert_metric_name=False)
+    assert ckpt_name == 'epoch=003-val_acc=0.03'
+
 
 class ModelCheckpointExtensionTest(ModelCheckpoint):
     FILE_EXTENSION = '.tpkc'