Solving Problems with Constraints Karen E. Petrie

What is a Scientist?  What do you think a scientist does?  Choose one task: Draw a picture of a scientist; Write a timetable for a scientist’s day (a timetable sheet is provided)

What is a scientist?  I am a scientist.  As are all the other adults in the room.  What does it mean to be a scientist?  What kind of work do we do?

What did you say you do?  Mathematician  I never could do maths  Computer science  My son plays…  Could you fix…  Artificial Intelligence

So: What is AI?  “ A singular consciousness that spawned an entire race of machines” Morpheus, The Matrix  “The scientific understanding of the mechanisms underlying thought and intelligent behaviour and their embodiment in machines." AAAI  “Making computers do anything that they can not currently do without human intervention” Karen Petrie

It’s not all about robots?

A Puzzle  Place the numbers 1 through 8 in the nodes such that: Each number appears exactly once ? ? ? ? ? ? ?? –No connected nodes have consecutive numbers You have 10 minutes!

Modeling  Each node  a variable  {1, …, 8}  values in the domain of each variable  No consecutive numbers  a constraint (v i, v j )  |v i – v j | > 1  All values used  all-different constraint

Heuristic Search ? ? ? ? ? ? ??18 {1, 2, 3, 4, 5, 6, 7, 8}

Inference/Propagation ? ? ? ? ? ? ?? 18 {1, 2, 3, 4, 5, 6, 7, 8}

Inference/Propagation ? ? ? ? ? ? ?? 18 {3, 4, 5, 6} {3, 4, 5, 6, 7}{2, 3, 4, 5, 6}

Research into Constraint Computation  Modelling What should the variables/domains/constraints be?  Heuristic Search How should search progress?  Inference/Propagation How much effort should be spent on inference?

More about CP  For the rest of the afternoon you can learn more about CP by playing with the puzzles at: If you have any questions or are stuck, than you can ask one of the `scientists’ for help!

Thanks for joining us today!