Case-insensitive optimizer name (#17287)

Co-authored-by: UltralyticsAssistant <web@ultralytics.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

ultralytics/engine/trainer.py

@@ -791,6 +791,8 @@ class BaseTrainer:
                 else:  # weight (with decay)
                     g[0].append(param)
 
+        optimizers = {"Adam", "Adamax", "AdamW", "NAdam", "RAdam", "RMSProp", "SGD", "auto"}
+        name = {x.lower(): x for x in optimizers}.get(name.lower(), None)
         if name in {"Adam", "Adamax", "AdamW", "NAdam", "RAdam"}:
             optimizer = getattr(optim, name, optim.Adam)(g[2], lr=lr, betas=(momentum, 0.999), weight_decay=0.0)
         elif name == "RMSProp":
@@ -799,9 +801,8 @@ class BaseTrainer:
             optimizer = optim.SGD(g[2], lr=lr, momentum=momentum, nesterov=True)
         else:
             raise NotImplementedError(
-                f"Optimizer '{name}' not found in list of available optimizers "
-                f"[Adam, AdamW, NAdam, RAdam, RMSProp, SGD, auto]."
-                "To request support for addition optimizers please visit https://github.com/ultralytics/ultralytics."
+                f"Optimizer '{name}' not found in list of available optimizers {optimizers}. "
+                "Request support for addition optimizers at https://github.com/ultralytics/ultralytics."
             )
 
         optimizer.add_param_group({"params": g[0], "weight_decay": decay})  # add g0 with weight_decay