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Thanks for the kind feedback. It's a young project to be honest, but I'm pretty proud of what we've done with only two contributors so far. With community parti

Thanks for the kind feedback. It's a young project to be honest, but I'm pretty proud of what we've done with only two contributors so far. With community participation I think we could support many more languages pretty quickly!

yomritoyj 7y ago
I really have always wished for reproducibility. Thanks for taking up this feature. How do you handle aliasing and references inside objects? Suppose I have #Cell 1 a = [1,2,3] b = (a,True) #Cell 2 b[0][0] = 5 #Cell 3 print(sum(a)) Now if I change Cell 2 to # Cell 2' b[0][0] = 4 and execute, Cell 3's result becomes stale. Do you track such dependencies? Would really love to read more about the underlying implementation.
- type_enthusiast 7y ago
  If you mutate an object itself, we can't really track that. There's no magic going on; you can break the state if you use mutable objects. It's less of an issue in Scala where immutable data structures are the norm, but I can imagine it would be disappointing in Python. Currently it takes a shallow copy of the state output by each cell, meaning every value is going to be a primitive value or a reference. If it's a reference to mutable state, you're kind of on your own with respect to keeping reproducibility. I felt like this was a good compromise between strictly enforced reproducibility and practicality; if it turns out to be confusing we could consider deep copying the state, or having an option to do that (I could imagine it being pretty bad for efficiency in a lot of ML use cases, though).
  - cm2187 7y ago
    I am not familiar with those notenooks. What would be wrong with re-executing all the cells below the one that changed?
    - steve19 7y ago
      That is usually a feature. The reason it's not the default everytime you change a cell if that cells can contain long running calculations.

yomritoyj 7y ago

I really have always wished for reproducibility. Thanks for taking up this feature. How do you handle aliasing and references inside objects? Suppose I have #Cell 1 a = [1,2,3] b = (a,True) #Cell 2 b[0][0] = 5 #Cell 3 print(sum(a)) Now if I change Cell 2 to # Cell 2' b[0][0] = 4 and execute, Cell 3's result becomes stale. Do you track such dependencies? Would really love to read more about the underlying implementation.

type_enthusiast 7y ago
If you mutate an object itself, we can't really track that. There's no magic going on; you can break the state if you use mutable objects. It's less of an issue in Scala where immutable data structures are the norm, but I can imagine it would be disappointing in Python. Currently it takes a shallow copy of the state output by each cell, meaning every value is going to be a primitive value or a reference. If it's a reference to mutable state, you're kind of on your own with respect to keeping reproducibility. I felt like this was a good compromise between strictly enforced reproducibility and practicality; if it turns out to be confusing we could consider deep copying the state, or having an option to do that (I could imagine it being pretty bad for efficiency in a lot of ML use cases, though).
- cm2187 7y ago
  I am not familiar with those notenooks. What would be wrong with re-executing all the cells below the one that changed?
  - steve19 7y ago
    That is usually a feature. The reason it's not the default everytime you change a cell if that cells can contain long running calculations.