1. 18/5 - 20071 VIP Elevator – second model A VDM++ Project Made By: Sune Wolff

2. 18/5 - 20072 Agenda Summary of First Model Desired Improvements Class Diagram Mapping Intelligent Elevator Intelligent Queue Achieved Improvements

3. 18/5 - 20073 Summary of First Model Basic first model FIFO queue for placing orders  Using ordered sequence of floors Elevator moved between floors in atomic fashion

4. 18/5 - 20074 Desired Improvements Introduce classes for buttons and sensors  Make use of mapping Make elevator more intelligent  Keep track of direction  Choose next floor based on direction and distance Introduce automatic test  Read test sequence from file Make sure the VIP receives special treatment  No neighbours in elevator when VIP wants to use it  Execute VIP order as soon as possible

5. 18/5 - 20075 Class Diagram

6. 18/5 - 20076 Mapping class EC instance variables public static floorMap : map Elevator`Floor to nat := { |-> -1, |-> 0, |-> 1, |-> 2, |-> 3, |-> 4}; public static invFloorMap : map nat to Elevator`Floor := inverse floorMap; end EC class Elevator operations public UpdateCurrent: Dir * Floor ==> Floor UpdateCurrent(dir, cur) == (dcl curNum : nat := EC`floorMap(cur); if (dir = and cur <> ) then curNum := curNum + 1 elseif (dir = and cur <> ) then curNum := curNum – 1; return EC`invFloorMap (curNum); ); end Elevator

7. 18/5 - 20077 Intelligent Elevator public MoveElevator: () ==> Floor MoveElevator() == (if (not EC`vipQueue.QueueEmpty() and EC`innerQueue.QueueEmpty()) then (nextFloor := EC`vipQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) elseif (not EC`innerQueue.QueueEmpty()) then (nextFloor := EC`innerQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) elseif (not EC`outerQueue.QueueEmpty()) then (nextFloor := EC`outerQueue.GetNextFromQueue(direction, currentFloor, nextFloor); currentFloor := UpdateCurrent(direction, currentFloor); return nextFloor) else (UpdateDir(direction); return ;

8. 18/5 - 20078 Intelligent Queue public GetNextFromQueue: Elevator`Dir * Elevator`Floor * Elevator`Floor ==> [Elevator`Floor] GetNextFromQueue(dir, cur, next) == (dcl nextFloor : Elevator`Floor := next; dcl nextSet : set of Elevator`Floor := {}; dcl top : Elevator`Floor := ; dcl bottom : Elevator`Floor := ; for all f in set elevatorQueue do (if (dir = and EC`floorMap(f) > EC`floorMap(cur)) then (nextSet := nextSet union {f}; for all nextF in set nextSet do (if (next = ) then (if (EC`floorMap(nextF) < EC`floorMap(top)) then (nextFloor := nextF; top := nextF;) elseif (EC`floorMap(nextF) < EC`floorMap(nextFloor)) then nextFloor := nextF;

9. 18/5 - 20079 Intelligent Queue #2 if (nextFloor <> next and next <> ) then (elevatorQueue := elevatorQueue union {next}; elevatorQueue := {y | y in set elevatorQueue & y <> nextFloor}; ) elseif (next = ) then elevatorQueue := {y | y in set elevatorQueue & y <> nextFloor}; return nextFloor;

10. 18/5 - 200710 Achieved Improvements Introduce classes for buttons and sensors  Make use of mapping Make elevator more intelligent  Keep track of direction  Choose next floor based on direction and distance Introduce automatic test  Read test sequence from file Make sure the VIP receives special treatment  No neighbours in elevator when VIP wants to use it  Execute VIP order as soon as possible ? ? VDMUnit