I can't get wall and floor materials

I'm successfully running the code and getting the output. I figured a way to also get the object-material for a given object but I have two problems:

1) I don't know how to get the accuracy of each prediction.
2) I don't know how to get the object-material relationship for the floor and the wall type of objects. No matter which picture I analyze, the program never finds materials for them. Maybe I'm missing something.