Add comment on Hartmann function

app.py

@@ -4,6 +4,7 @@ from torch import Tensor
 
 
 def hartmann(x1, x2, x3, x4, x5, x6):
+    # Six dimensional Hartmann function
     x_tensor = Tensor((x1, x2, x3, x4, x5, x6))
     hartmann_function = Hartmann(dim=6)
     y = hartmann_function(x_tensor)