Allow scheduler parameters (#26480)

* Allow for scheduler kwargs

* Formatting

* Arguments checks, passing the tests

* Black failed somehow

---------
Co-authored-by: Pierre <pierre@avatarin.com>

src/transformers/optimization.py

@@ -337,6 +337,7 @@ def get_scheduler(
     optimizer: Optimizer,
     num_warmup_steps: Optional[int] = None,
     num_training_steps: Optional[int] = None,
+    scheduler_specific_kwargs: Optional[dict] = None,
 ):
     """
     Unified API to get any scheduler from its name.
@@ -352,6 +353,9 @@ def get_scheduler(
         num_training_steps (`int``, *optional*):
             The number of training steps to do. This is not required by all schedulers (hence the argument being
             optional), the function will raise an error if it's unset and the scheduler type requires it.
+        scheduler_specific_kwargs (`dict`, *optional*):
+            Extra parameters for schedulers such as cosine with restarts. Mismatched scheduler types and scheduler
+            parameters will cause the scheduler function to raise a TypeError.
     """
     name = SchedulerType(name)
     schedule_func = TYPE_TO_SCHEDULER_FUNCTION[name]
@@ -372,7 +376,15 @@ def get_scheduler(
     if num_training_steps is None:
         raise ValueError(f"{name} requires `num_training_steps`, please provide that argument.")
 
-    return schedule_func(optimizer, num_warmup_steps=num_warmup_steps, num_training_steps=num_training_steps)
+    if scheduler_specific_kwargs is None:
+        scheduler_specific_kwargs = {}
+
+    return schedule_func(
+        optimizer,
+        num_warmup_steps=num_warmup_steps,
+        num_training_steps=num_training_steps,
+        **scheduler_specific_kwargs,
+    )
 
 
 class AdamW(Optimizer):

src/transformers/trainer.py

@@ -1137,6 +1137,7 @@ class Trainer:
                 optimizer=self.optimizer if optimizer is None else optimizer,
                 num_warmup_steps=self.args.get_warmup_steps(num_training_steps),
                 num_training_steps=num_training_steps,
+                **self.args.lr_scheduler_kwargs,
             )
             self._created_lr_scheduler = True
         return self.lr_scheduler

src/transformers/training_args.py

@@ -238,6 +238,8 @@ class TrainingArguments:
             when all data is exhausted
         lr_scheduler_type (`str` or [`SchedulerType`], *optional*, defaults to `"linear"`):
             The scheduler type to use. See the documentation of [`SchedulerType`] for all possible values.
+        lr_scheduler_kwargs ('dict', *optional*, defaults to {}):
+            The extra arguments for the lr_scheduler. See the documentation of each scheduler for possible values.
         warmup_ratio (`float`, *optional*, defaults to 0.0):
             Ratio of total training steps used for a linear warmup from 0 to `learning_rate`.
         warmup_steps (`int`, *optional*, defaults to 0):
@@ -729,6 +731,14 @@ class TrainingArguments:
         default="linear",
         metadata={"help": "The scheduler type to use."},
     )
+    lr_scheduler_kwargs: Optional[Dict] = field(
+        default_factory=dict,
+        metadata={
+            "help": (
+                "Extra parameters for the lr_scheduler such as {'num_cycles': 1} for the cosine with hard restarts"
+            )
+        },
+    )
     warmup_ratio: float = field(
         default=0.0, metadata={"help": "Linear warmup over warmup_ratio fraction of total steps."}
     )