Articial life simulation
Common features:
Population of agents/indidividuals
2D (or 3D) environment
Reproduction & evolution
Emergent complex behavior:
micro macro-behavior
Uncommon feature:
Physics and chemistry of microworld (A Dorin)
Applications
Denition 3 (Homomorphism)
A homomorphism is a mapping (function) from one structure (system) to another which
preserves relations, functions etc. in the rst under the mapping into the second.
Example:
Consider the two systems:
1. hN, +, Oddi
2. hcfw_0, 1,
CSE 3305 Assignment 1
Due: 23/3/07 5pm Weight: 10%
Assignments are to be submitted by email in a plain text (ascii) attachment (not html, doc or any other format). Whenever possible, answers are to be in the form: Num: Ans one per line, where Num is repla
Complexity Analysis
There are three main kinds of complexity analysis:
1. Worst case analysis
Useful for avoiding catastrophe. Variations: best case, etc.
2. Average (mean) case analysis
E.g., Ave(g(n) = E[g(n)] = P
i P(i)g(i), involving
a formal analysis
Modeling Choices
Modeling choices determine:
Adequacy of the model: can it represent the system of interest?
Efciency of the model: is the search space tractable?
Intelligibility of the model: can people understand it?
The main modeling choices are:
L
Two possible representations for Tic-Tac-Toe (noughtsand crosses):
1. Bit string of 2 bit elds
00: empty
01: X
10: O
11: (meaningless)
2. Matrix of 0, 1, 2 (integers)
Disadvantages
25% of the state space is wasted
If search is by random bit mutation
Different Orders
Search Complexity
Problem:
Search for x in an ordered list ()
L = hL1, . . . , Lni
returning the index or nil
We all know the algorithm!
1. i 1;
2. LOOP: IF Li = x RETURN i;
3. INC i;
4. IF i > n RETURN NIL;
5. GO LOOP;
Whats O(f)? Averag
Exhaustive Search
Denition 7 (Exhaustive search) Exhaustive search (potentially) examines every state of the
search space, for the optimum (given cost) or the goal state.
Exhaustive methods are worth considering because
Not all search spaces are as bad a
Discrete Event Simulation
Pick up the telescope and turn it around:
Basic unit of simulation is neither time nor agents
but
Events
Events occur (or, nish, really) in their own sweet time, whenever they are ready.
Time is not stepped, but added to
The
What is Computer Science?
Theory
Limits of computation
Complexity: abstract comp theory; practical (analysis of algs)
Method
Problem solving, search
Simulation: stochastic search; discrete-state sim; articial life; articial economics
Application
A