Refactor get_n_parts function to simplify code and improve readability

convert-pth-to-ggml.py

@@ -37,17 +37,16 @@ fname_hparams   = sys.argv[1] + "/params.json"
 fname_tokenizer = sys.argv[1] + "/../tokenizer.model"
 
 def get_n_parts(dim):
-    if dim == 4096:
+    mappings = {
-        return 1
+        4096: 1,
-    elif dim == 5120:
+        5120: 2,
-        return 2
+        6656: 4,
-    elif dim == 6656:
+        8192: 8
-        return 4
+    }
-    elif dim == 8192:
+    if dim not in mappings:
-        return 8
+        print(f"Invalid dim: {dim}")
-    else:
-        print("Invalid dim: " + str(dim))
         sys.exit(1)
+    return mappings[dim]
 
 # possible data types
 #   ftype == 0 -> float32