add current_epoch to dumped_params (#3261)

* add current epoch to __dumped_params

* log

* reset

* add to test

* Update CHANGELOG.md

Co-authored-by: Adrian Wälchli <aedu.waelchli@gmail.com>

Co-authored-by: Jirka Borovec <jirka@pytorchlightning.ai>
Co-authored-by: Nicki Skafte <skaftenicki@gmail.com>
Co-authored-by: Adrian Wälchli <aedu.waelchli@gmail.com>

CHANGELOG.md

@@ -104,6 +104,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed counter-intuitive error being thrown in `Accuracy` metric for zero target tensor ([#3764](https://github.com/PyTorchLightning/pytorch-lightning/pull/3764))
 
+- Fixed Tuner dump: add `current_epoch` to dumped_params ([#3261](https://github.com/PyTorchLightning/pytorch-lightning/pull/3261))
+
 - Fixed aggregation of metrics ([#3517](https://github.com/PyTorchLightning/pytorch-lightning/pull/3517))
 
 - Fixed `current_epoch` and `global_step` properties mismatch between `Trainer` and `LightningModule` ([#3785](https://github.com/PyTorchLightning/pytorch-lightning/pull/3785))

pytorch_lightning/tuner/batch_size_scaling.py

@@ -123,6 +123,7 @@ def __scale_batch_dump_params(trainer):
     # Prevent going into infinite loop
     trainer.__dumped_params = {
         'auto_lr_find': trainer.auto_lr_find,
+        'current_epoch': trainer.current_epoch,
         'max_steps': trainer.max_steps,
         'weights_summary': trainer.weights_summary,
         'logger': trainer.logger,
@@ -138,6 +139,7 @@ def __scale_batch_dump_params(trainer):
 def __scale_batch_reset_params(trainer, model, steps_per_trial):
     trainer.auto_scale_batch_size = None  # prevent recursion
     trainer.auto_lr_find = False  # avoid lr find being called multiple times
+    trainer.current_epoch = 0
     trainer.max_steps = steps_per_trial  # take few steps
     trainer.weights_summary = None  # not needed before full run
     trainer.logger = DummyLogger()
@@ -151,6 +153,7 @@ def __scale_batch_reset_params(trainer, model, steps_per_trial):
 
 def __scale_batch_restore_params(trainer):
     trainer.auto_lr_find = trainer.__dumped_params['auto_lr_find']
+    trainer.current_epoch = trainer.__dumped_params['current_epoch']
     trainer.max_steps = trainer.__dumped_params['max_steps']
     trainer.weights_summary = trainer.__dumped_params['weights_summary']
     trainer.logger = trainer.__dumped_params['logger']

tests/trainer/test_trainer_tricks.py

@@ -182,7 +182,8 @@ def test_trainer_reset_correctly(tmpdir):
                           'callbacks',
                           'checkpoint_callback',
                           'early_stop_callback',
-                          'limit_train_batches']
+                          'limit_train_batches',
+                          'current_epoch']
 
     attributes_before = {}
     for ca in changed_attributes: