1. Incremental Computation
in Python
Phillip Schanely
pschanely @medium
pschanely @twitter

2. The New Messaging App

4. You have no new messages
Joe IDK, let’s go to Sal’s
Sarah LOLZ
Mike Right? I’ve never …

5. You have no new messages
Joe IDK, let’s go to Sal’s
Sarah LOLZ
Mike Right? I’ve never …

6. You have no new messages
Joe IDK, let’s go to Sal’s
Sarah LOLZ
Mike Right? I’ve never …

9. The Model-View Problem
Incremental MapReduce in Python
Contents:

10. The Model-View Problem

11. Model, M
View, V

12. Model, M
State Change
Model, M’
View, V

13. Model, M
State Change
Model, M’
View, V View, V’
Decision Time!

14. Model, M
State Change
Recompute
Model, M’
View, V View, V’

15. Model, M
State Change
Infer
Model, M’
View, V View, V’

16. Model, M
State Change
Invalidate
Model, M’
View, V View, V’

17. Recompute
Invalidate
Infer

18. Recompute
Invalidate
Infer
Incremental MapReduce

19. It’s Everywhere

20. Javascript
Objects
DOM
Javascript
Objects
DOM
Web Apps
Infer
Recompute

21. DOM
Pixels
DOM
Pixels
Browsers
Invalidate

22. Application
Pixels
Display
Application
Pixels
Display
OS Display
Infer

23. Database
State
API
Responses
Database
State
API
Responses
Backend Logic
Recompute

24. Normalized
Data
Computed
Data
Normalized
Data
Computed
Data
Application
Databases
Infer
Recompute

25. Database
Row
Database
Index
Database
Row
Database
Index
Databases
Infer

26. RAM
Processor
Cache
RAM
Processor
Cache
Multiprocessor
L1/L2 caches
Invalidate

27. Code
Build
Code
Build
Build Systems
Recompute

28. Code
Test
Results
Code
Test
Results
Test Runners
Recompute

29. Incremental MapReduce

30. Model, M
State Change
Model, M’
View, V View, V’
Incremental
MapReduce

31. 4 6
10
1 5
6
16

32. 4 6
10
1 5
6
16
4 6 1 5
3
Insert “3”

33. 4 6
10
1 5
6
16
4 6 1 5
3
Insert “3”
10 9
19
4

34. ScenicOverlook
$ pip install ScenicOverlook

35. 4 6 1 5
>>> l = viewablelist([4,6,1,5])

36. 4 6 1 5
>>> l = viewablelist([4,6,1,5])
>>> add = lambda x, y: x + y
>>> l.reduce(add, initializer=0)
16

37. 4 6 1 5 4 6 1 5
3
Insert “3”
>>> l = viewablelist([4,6,1,5])
>>> add = lambda x, y: x + y
>>> l.reduce(add, initializer=0)
16
>>> l = l[:2] + [3] + l[2:]

38. 4 6 1 5 4 6 1 5
3
Insert “3”
>>> l = viewablelist([4,6,1,5])
>>> add = lambda x, y: x + y
>>> l.reduce(add, initializer=0)
16
>>> l = l[:2] + [3] + l[2:]
>>> l.reduce(add, initializer=0)
19

39. >>> import heapq
>>> def sort(l):
... l = l.map(lambda x:[x])
... return l.reduce(heapq.merge,
initializer=())
>>> l = viewablelist([9, 3, 5, 7])
>>> sort(l)
[3, 5, 7, 9]
>>> sort(l + [ 4 ])
[3, 4, 5, 7, 9]
3 5 79
9 5 73
5 7 93

40. Graphics Demo

41. $ python demo_graphics.py

45. Compiler Demo

46. $ python demo_graphics.py

48. Normalize

49. Generate Call Tree
Normalize

50. Type Check
Generate Call Tree
Normalize

51. Type Check
Generate Call Tree
Normalize
LLVM Generation

52. Type Check
Generate Call Tree
Normalize
LLVM Generation
link

53. Umut Acar (CMU): “self-adjusting computation”
Matthew A. Hammer: “Adapton”
Interesting Related Work

54. github.com/pschanely/ScenicOverlook
pschanely @medium
pschanely @twitter
Questions?