1.9.3 Derived Variables Video
The technique of derived variables comes up in analyzing state machines. So let's just take a quick look at it together. So a derived variable is simply a function on the states of a state machine that assigns some value to the states. So it's just that kind of a function mapping. If the values happen to be, say, the non-negative integers, it's called non-negative integer value, but it could be real value, complex value, and even take on other kinds of odd kinds of values, not necessarily numerical. No pun there-- not odd numbers, but unusual values. So let's look at the example of the robot on the grid. The states were pairs of non-negative integers giving the coordinates of where the robot was. And one of the derived variables that we found was real useful was the sum value, sigma, of a state, which is defined to be x plus y. And this would be a non-negative integer valued derived variable. So the word "derived" comes because we're making i...