1. Introduction to Computing
for Complex Systems
(Lab Session 1)
daniel martin katz
illinois institute of technology
chicago kent college of law
@computationaldanielmartinkatz.com computationallegalstudies.com

2. Implementation:
From Concept to Product

3. Implementation
It is important to understand the canonical
scholarship as highlighted in the lecture
However, model implementation and the mechanics
of other forms of analysis is often the barrier to
entry for most scholars
Implementation is the link between concept and
scientific product

4. Different Software Packages
Netlogo = Introductory Modeling Environment
(Agent Based Models & System Dynamics)
R = Platform for Statistical Analysis
(Includes the IGraph Library for Networks)
Vensim / Nova = Development of System Dynamics
and Ecological Models
Pajek = Basic Software for Empirical Analysis
& Visualization of Networks
Python = Object Oriented Programming Language
Flexible and Fast but High Bar to Entry

5. Getting Started In

6. Getting Started In Netlogo
Netlogo is an Introductory Modeling Environment
Developed By Uri Wilensky @ Northwestern in 1999
Maintained by Center for Connected Learning &
Computer-Based Modeling @ Northwestern

7. Getting Started In Netlogo
Syntax is Inherited from the old “Logo” Language
Resnick (1991)
Wilensky (1999)
Papert & Minsky (1967)

8. Getting Started In Netlogo
Features Aspects of Programming But is Not a
General Language ( C++, Python, Java)
Arguably Easier To Learn Than A General Language
Serves the Implementation Needs of Many Modelers

9. Getting Started In Netlogo
Agent Based Models, System Dynamics Models,
Network Models, GIS, Etc.
Download @ ccl.northwestern.edu/
Should Also Acquire User Manual & Dictionary
Version 4.1, Version 4.1 3D, Version 3.1.5

10. Getting Started In Netlogo
HIV / AIDS VOTING

11. Where To Get Help

12. Where To Get Help

13. Netlogo
Front
Page

14. Getting Started in Netlogo

15. Getting Started in Netlogo
Files Have a Extension of .nlogo

16. Interface
Information
Procedures

17. Interface
Information
Procedures

18. Edit the
Information

19. Interface
Information
Procedures

20. Code for
the
Schelling’s
Segregation
Model

22. The Models Library
Explore the
Available
Models

23. Getting Started in Netlogo

26. Getting Started in Netlogo

27. Getting Started in Netlogo

29. Getting Started in Netlogo

30. Controls
executes specific
commands “on the fly”
Buttons
Command Center
“once” buttons execute one Action
“forever” buttons repeat the same action
(Until Stopped)

31. Settings
Sliders
Switchers
Select a value from a list
Adjust a quantity by increments
Choosers
Set a Boolean variable
(true/false)

32. Monitors
Plots
Offers the Current
Value of Variables
Displays the Time Series Plot for
a Given Variable or Variables
Views

33. The Netlogo Language

34. Four Types of Agents
Patches
Turtles
Links
The Observer

35. Patches
Tile
System
with
(0,0)
Center
Origin
pxcor
min-­‐pxcor
max-­‐pxcor
world-­‐height
world-­‐width

36. View the Settings

37. View the
Settings

38. View the
Settings

39. View the
Settings

40. View the
Settings

41. What is a
Torus?
Why is It
33 x 33?
View the
Settings

42. Patches: Key Things
Patches do not move -- they are fixed
Patches can breed turtles
Patches can have assigned variables
Patches belong to an agent set

43. Consulting the Netlogo Dictionary
Descriptions of
Patch Primitives
Can Be Accessed
Through the
Netlogo
Dictionary

44. Turtles
Turtles
move
on
top
of
the
patches
Have
decimal
coordinates
(xcor,
ycor)
Have
an
orientation
(heading)
Can
have
different
shapes

45. Turtles
Classic
Hawk
&
Dove
Model
from
Evolutionary
Game
Theory
Runs
in
Netlogo
Version
3.1.5

46. Inspect Turtles
Right Click on a Turtle
(Ctrl + Click on Mac)

47. Watch a Specific Turtle
Right Click on a Turtle
(Ctrl + Click on Mac)

48. Lots of Different Turtle Shapes

49. Turtles: Key Things
Turtles move around the environment
Turtles can have various shapes
Turtles can have different variables
Turtles belong to an agent set

50. Colors
color
=
agents
pcolor
=
patches
Select
a
Major
Color
by
Name
Customize
Colors
Using
##
from
Chart

52. Exploring the
Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

53. The Forest Fire Model

54. The Forest Fire Model

55. The Forest Fire Model

56. The Forest Fire Model

57. The Forest Fire Model

58. The Forest Fire Model

59. The Forest Fire Model

60. The Forest Fire Model

61. The Forest Fire Model

62. The Forest Fire Model

63. The Forest Fire Model

64. The Forest Fire Model

65. The Forest Fire Model

66. The Forest Fire Model

67. The Forest Fire Model

68. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

69. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

70. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

71. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

72. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

73. The Forest Fire Model
http://ccl.northwestern.edu/netlogo/models/Fire

74. http://ccl.northwestern.edu/netlogo/models/Fire
The Forest
Fire Model

75. Tally the Average of
five model runs
For Values
50, 55, 60, 65

76. The Forest Fire Model
Average
2.6

77. The Forest Fire Model
Average
2.6
Average
5.8

78. The Forest Fire Model
Average
2.6
Average
5.8
Average
66.5

79. The Forest Fire Model
Average
2.6
Average
5.8
Average
66.5
Average
93.9

80. Average
5.8
Average
66.5
Parallel Processing on
Percolation Threshold

81. Lets Do Some additional
in Class Data Collection
On Our Fire Model
56
57
58
59

82. Now Lets
Discuss
The Results

83. Explore the Code

86. The Forest
Fire Model

88. ;; is for
Comments
Not Active
code

89. What is a Global?
Look it up in
the dictionary

90. What is a Global?

93. What is a breed?
again, look it up in
the dictionary

94. What is a breed?

95. The Forest
Fire Model

96. The Forest
Fire Model

97. Introduction to Computing
for Complex Systems
(Lab Session 1)
daniel martin katz
associate professor of law | illinois tech - chicago kent law
blog | ComputationalLegalStudies
corp | LexPredict