Lecture 1: Evolutionary problem solving
Kickoff
● Evolution can create intelligence
● Artificial evolution can create artificial intelligence
● Generic system architecture: Triangle of Life
What is Evolutionary Computing (EC)?
● The field for designing, applying, and studying evolutionary algorithms
● What is an evolutionary algorithm?
● What is evolution?
● What is an algorithm?
○ Set of steps to accomplish a task
○ What makes it good: correctness and efficiency
○ Asymptotic analysis: computing the running time of any operation in
mathematical units of computation
■ To determine which algorithm is more efficient
Evolutionary heuristic example: 8 queens problem
● Eight queens need to be placed on a chess board such that no two queens can check
each other
● Good or bad?
Good bad
1
,General (implicit) vs. specific (explicit)
● General: N > 1 queens
● Specific: N = 8
● The property “size” is sufficiently specific
● Problem ≠ problem instance
8 queens solver
● Method 1
○ Place queens one by one
○ Fill rows from top to bottom, within a row: first available from left to right
○ Backtrack if stuck
■ Works by extending an empty solution – constructive method
■ Recursive
■ Blind
■ Search trajectory via correct but incomplete configurations
● Method 2 (is the same as method 1), but
○ Within a row: choose position that checks the least number of other positions
○ scan from left to right
2
, ■ Works by extending an empty solution – constructive method
■ Recursive
■ Heuristic: try to minimize need for backtracks
■ Search trajectory via correct but incomplete configurations
● Method 1 vs. Method 2
First possible Minimize “checks”
● Method 3
○ Place all queens
○ Repair errors by
■ Choose queen with the most conflicts
■ Move it to the best position in the same row
○ “best position”= with the min. number of conflicts
○ Random move if stuck
■ Works by improving a solution – iterative improvement method
■ Heuristic: try to maximize improvement via “educated guess”
■ Search trajectory via complete but incorrect configurations
● Method 4
○ Place all queens
○ Improve configuration by
■ Make K > 1 new configurations by a few random changes (“mutations”)
■ Discard the worst K-1 “mutants” (thus keep the best only)
○ Iterate
■ Works by improving a solution – iterative improvement method
3
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller tararoopram. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.00. You're not tied to anything after your purchase.