1. Object Oriented Framework for Filtering
Jonathan Wiersma
Jarett Hailes
MITACS-PINTS

2. Presentation Overview
Overview of Programming Concepts
Procedural Programming
Object Oriented Design
Current State of PINTS Projects
Proposed Improvements
Filtering project framework
Common Interfaces
Shared set of utility classes
Refactoring
Implementation and Challenges
Conclusion & Future Directions

3. Procedural Programming - Overview
integer
char
Variables
float
pointer
Data Structures
combinations of previous
Functions
multiple inputs (parameters)
single output (return value)
Different than functions in math:
May map same input to different outputs
behavior can depend on state of global variables
variables are mutable

4. Procedural Programming – Example 1
Global variable (accessible to all functions)
int global_var;
void main() {
int a,b,c;
a = 3;
b = 4;
c = sum(a,b);
output(c); }
int sum(int x, int y) {
return x + y;
function
variables
Variable assignment
Function call

5. Object Oriented Design - Basics
Objects
Classes
Variables/State
Methods

6. Object Oriented Design - Classes
Combines a data structure (set of variables) with operations related to that data structure (methods)
Describes a class of objects (like a set)
An object is an instance of a class and has a state

7. Object Oriented Programming: Code Structure
Procedural Program:
Object Oriented Program:
Data Structures
Global variables
Class 1
Data Structure
methods
Procedures/functions
Class 2
Data Structure
methods

8. Object Oriented Design - Concepts
Encapsulation
Inheritance
Polymorphism

9. State of Code at PINTS Each project is a completely separate entity
Interfaces are different between projects
Interfaces are not clearly defined (templates)
No code reuse – improvements only effect one project
Large undertaking to create a new project
Not easy to read and understand

10. Improvements being Developed
Create a filtering project framework
Shared underlying structure
Suite of useful utility classes
Abstract output model (M-V-C pattern)

11. Framework for Filtering Projects
Create a set of generic classes and interfaces (via inheritance)
Have filters use these generic interfaces so they don’t require customized code
Design a framework to ease the development effort of applying a filter to a new application

12. Shared Filtering Interface
SERP Filter
DType
Signal
Observation
Observer
POD Signal
POD 13 Observation
POD 13 SERP Observer

13. CVS – Concurrent Versioning System
Allows several users to work on the same files at the same time
Stores old versions and changes
Also useful for text and latex documents

14. CVS Layout

15. Interfaces Filter SERP Filter DType Signal Observation Observer
POD Signal
POD 13 Observation
POD 13 SERP Observer

16. Interfaces Signal BoundedSignal DType position void evolve()
AbsDomain domain
AbsDomain domain()

17. Interfaces Observation ODType position void observe(Signal, double dt)

18. Interfaces Observer SERP Observer Observation
void observe(Observation, double dt)
SERP Observer
double weightedOffset(Signal, double dt)

19. CVS Math Package - Algebra
Ideally:
Matrix
Row Matrix
Column Matrix
Row Vector
Column Vector

20. CVS Math Package - Algebra
Row Vector
Scalar values[]
int dimension
math operators (+,-,*,+=,-=,*=,etc)
accessors
RowVector norm()
void normalize()

21. CVS Math Package - Algebra
Column Vector
Scalar values[]
int dimension
math operators (+,-,*,+=,-=,*=,etc)
accessors
ColumnVector norm()
void normalize()

22. CVS Math Package - Algebra
Row Matrix
RowVector values[]
int nrows, ncols
math operators (+,-,*,+=,-=,*=,etc)
accessors
RowMatrix inverse()
void invert()

23. CVS Math Package - Coordinates
Euclidean Coordinate
Polar Coordinate

24. CVS Math Package - Coordinates
CType value
math operators (+,-,*,+=,-=,*=,etc)
accessors

25. CVS Math Package - Coordinates
Polar Coordinate
CType max, min
math operators (+,-,*,+=,-=,*=,etc)
accessors

26. CVS Math Package - Domain
Abstract Domain
Abstract Bounded Domain
Vector Box Domain

27. CVS Math Package - Domain
Abstract Domain
bool contains(DType)
Abstract Bounded Domain
DType min, max
DType min()
DType max()

28. CVS Math Package - Domain
Range Type
Abstract Function
Domain Type
Continuous Function
Discrete Function

29. CVS Math Package - Domain
Abstract Function
int dimension
Range operator()(Domain val)
int dimension()
Range Type
Domain Type

30. CVS Math Package - Domain
Abstract Function
Range Type
int dimension
Domain Type
Range operator()(Domain val)
int dimension()
Continuous Function
Range operator()(Domain val)
DiscreteFunction discretize()
DiscreteFunction fft(VBoxDom<DType>, int)

31. CVS Math Package - Domain
Abstract Function
Range Type
int dimension
Domain Type
Range operator()(Domain val)
int dimension()
Discrete Function
VectorBoxDomain<DType> domain
MultiDArray<RType> data
int numDivisions
DType delta[]
RType index(int idx[])
DiscreteFunction fft(int type)
accessors

32. Graphics - Legacy Packages of raster graphics procedures Outdated
Custom code
Not supported
Very low level

33. Graphics - povray 3D Ray Tracing program Beautiful output
Slow Rendering
Separate Application
Requires specific input format

34. Graphics - VTK Object Oriented 3D Visualization Toolkit
Uses standard visualization network
Fairly fast
Easy to incorporate into real-time display
Support for several languages

35. Graphics – Output Classes
Text Output
PovRay Output
VTK Output
POD 13 PovRay Output
POD 13 VTK Output

36. Utilities - Simulations
Abstract Simulation Classes
Rapid Simulation Development
Code reuse
Standard Code Layout
Signal Simulation
Observation Simulation
Filter Simulation

37. Utilities - Simulations
Controller
Simulation
View
Model
Simulation View
Simulation Model
POD 13 Filter View 1
Filter Simulation Model
Filter
Output
SERP Filter
Signal
Observation
Text Output
VTK Output
POD Signal
POD 13 Observation

38. Utilities - Structures
Data Structures
Hash Table / Hash Bin
List
Multi Dimensional Array
Dictionary
We’ve made some container data structures for use in all other directories. Are there to facilitate portability of data across classes (much like Vector and matrix classes in math)
Most containers are templatable.

39. Refactoring Splitting large classes into smaller ones
Better encapsulation
Fewer variables to remember
Fewer methods to remember
More abstraction
Splitting large methods into smaller ones
Less code to read through to understand method
Easier to reuse code
Moving methods (feature envy)
Easier to understand
Easier to locate

40. Implementation Signal – evolve() Observation - observe(Signal)
Observer – depends on filter(s) used
Output – output()

41. Challenges Multiple Inheritance Return by value Graphics MVC Model
Observer Interfaces
Return by value
multiple copies
inheritance
Graphics MVC Model
templates

42. Future Directions Single Filtering Application for all Projects
Scripting Language
Language Change (java?)
Talk on using CVS for latex papers
Suggestions