I already explained how your circuit works on one of your other threads or on another website.
Or maybe I explained it to another kid in your class.
Did you ask your teacher to explain how it works?
User kewl has asked that this thread be removed because it was in regards to his homework. First it should have been submitted in the homework thread.
Second our answers are here for everyone to learn from.
The circuit is an active precision full-wave rectifier. When it is powered properly it works perfectly.
Don't delete this thread because somebody might learn something.