1. Promise make your python code faster by promising to behave yourself Ryan Kelly [email_address]

3. The How

4. The Why

6. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

7. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total timeit: 83

8. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

9. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 l_items = items while i < len( l_items ): total += calculate( l_items[i] ) i += 1 return total

10. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.invariant([“items”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total

11. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.invariant([“items”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total timeit: 83 73

12. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

13. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate( len=len ): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

14. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.constant([“len”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total

15. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.constant([“len”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total timeit: 83 77.1

16. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

17. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): x = items[i] total += 3*x*x - 2*x + (1 / x) i += 1 return total

18. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

19. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.constant([“calculate”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total

20. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.constant([“calculate”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total timeit: 83 60.5

21. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.invariant([“items”]) @promise.constant([“len”,“calculate”]) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total

22. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.sensible() def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total

23. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total promise.sensible()(globals())

24. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len( items ): total += calculate( items[i] ) i += 1 return total promise.sensible()(globals()) timeit: 83 56.5

25. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): i = 0 total = 0 while i < len(items): total += calculate(items[i]) i += 1 return total

26. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): return sum(calculate(i) for i in items)

27. items = [random.randint(0,100) for _ in xrange(100)] def calculate(x): return 3*x*x - 2*x + (1 / x) def aggregate(): return sum(calculate(i) for i in items) timeit: 83 59

28. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.sensible() def aggregate(): return sum(calculate(i) for i in items)

29. items = [random.randint(0,100) for _ in xrange(100)] @promise.pure() def calculate(x): return 3*x*x - 2*x + (1 / x) @promise.sensible() def aggregate(): return sum([calculate(i) for i in items]) timeit: 83 42.6

31. byteplay http://code.google.com/p/byteplay/ don't hack bytecode without it

32. >>> a = 1 >>> def add_a(b): ... return a + b ... >>>

33. >>> a = 1 >>> def add_a(b): ... return a + b ... >>> >>> >>> dis.dis(add_a) LOAD_GLOBAL 0 (a) LOAD_FAST 0 (b) BINARY_ADD RETURN_VALUE >>>

34. >>> a = 1 >>> @promise.invariant([&quot;a&quot;]) ... def add_a(b): ... return a + b ... >>>

35. >>> a = 1 >>> @promise.invariant([&quot;a&quot;]) ... def add_a(b): ... return a + b ... >>> >>> >>> dis.dis(add_a) LOAD_GLOBAL 0 (a) STORE_FAST 1 (_promise_var1_a) LOAD_FAST 1 (_promise_var1_a) LOAD_FAST 0 (b) BINARY_ADD RETURN_VALUE >>>

36. >>> a = 1 >>> @promise.constant([&quot;a&quot;]) ... def add_a(b): ... return a + b ... >>>

37. >>> a = 1 >>> @promise.constant([&quot;a&quot;]) ... def add_a(b): ... return a + b ... >>> >>> >>> dis.dis(add_a) LOAD_CONST 1 (1) LOAD_FAST 0 (b) BINARY_ADD

38. >>> a = 1 >>> def calc(): ... return add_a(7) ... >>> def add_a(b): ... return a + b ... >>>

39. >>> a = 1 >>> def calc(): ... return add_a(7) ... >>> def add_a(b): ... return a + b ... >>> >>> dis.dis(calc) LOAD_GLOBAL 0 (add_a) LOAD_CONST 1 (7) CALL_FUNCTION 1 RETURN_VALUE >>>

40. >>> a = 1 >>> @promise.constant([&quot;add_a&quot;]) ... def calc(): ... return add_a(7) ... >>> @promise.pure() ... def add_a(b): ... return a + b ... >>>

41. >>> a = 1 >>> @promise.constant([&quot;add_a&quot;]) ... def calc(): ... return add_a(7) ... >>> @promise.pure() ... def add_a(b): ... return a + b ... >>> >>> dis.dis(calc) LOAD_CONST 1 ( <function apply_deferred_promises> ) LOAD_CONST 2 (<function calc>) CALL_FUNCTION 1 POP_TOP LOAD_GLOBAL 0 (add_a) LOAD_CONST 3 (7) CALL_FUNCTION 1 RETURN_VALUE >>>

42. >>> calc._promise_deferred [<promise.constant object at 0xb77a5b0c>] >>>

43. >>> calc._promise_deferred [<promise.constant object at 0xb77a5b0c>] >>> >>> calc() 8 >>>

44. >>> calc._promise_deferred [<promise.constant object at 0xb77a5b0c>] >>> >>> calc() 8 >>> >>> dis.dis(calc) LOAD_CONST 1 (7) STORE_FAST 0 (_promise_var3_b) LOAD_CONST 2 (1) LOAD_FAST 0 (_promise_var3_b) BINARY_ADD JUMP_ABSOLUTE 16 RETURN_VALUE >>>

46. For fun!

47. For fun! None of my production code is CPU-bound

50. You probably don't need to optimise that

52. You probably don't need to optimise that

53. You probably need a better algorithm

55. come fork me: http://github.com/rfk/promise/