Allow setting num_cycles for cosine_with_restarts lr scheduler (#3606)

Expose num_cycles kwarg of get_schedule() through args.lr_num_cycles.

examples/textual_inversion/textual_inversion.py

@@ -285,6 +285,12 @@ def parse_args():
     parser.add_argument(
         "--lr_warmup_steps", type=int, default=500, help="Number of steps for the warmup in the lr scheduler."
     )
+    parser.add_argument(
+        "--lr_num_cycles",
+        type=int,
+        default=1,
+        help="Number of hard resets of the lr in cosine_with_restarts scheduler.",
+    )
     parser.add_argument(
         "--dataloader_num_workers",
         type=int,
@@ -739,6 +745,7 @@ def main():
         optimizer=optimizer,
         num_warmup_steps=args.lr_warmup_steps * args.gradient_accumulation_steps,
         num_training_steps=args.max_train_steps * args.gradient_accumulation_steps,
+        num_cycles=args.lr_num_cycles * args.gradient_accumulation_steps,
     )
 
     # Prepare everything with our `accelerator`.