関数プログラマから見たPythonと機械学習
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The document discusses various programming languages, primarily focusing on Python and its features such as type checking with mypy, data handling with libraries like NumPy and pandas, and integration with Haskell. It covers comparisons of typing systems, including dynamic and static typing, and looks at related frameworks and libraries. Additionally, it references potential type errors in Python functions and performance comparisons with other languages.
![Python
• ……
Python
• ) numpy.array ==
– numpy …
– Python
⇒
– sorted([np.zeros(2), np.zeros(2)])
• ( collections-extended
RangeMap )](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-9-320.jpg)
![: ……
• ……
•
……
• ) pandas itertuples
type(next(pd.DataFrame({"x" + str(i): [i] for i in range(253)}).itertuples()))
#=> pandas.core.frame.Pandas
type(next(pd.DataFrame({"x" + str(i): [i] for i in range(254)}).itertuples()))
#=> tuple](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-10-320.jpg)
![: Lisp-1
•
– Scheme, JavaScript
– Common Lisp, Ruby Lisp-2 ( )
•
Python Ruby
obj.foo(args) obj.foo(args)
( ) obj.foo() obj.foo(), obj.foo
obj.foo obj.method(:foo)
m(args) m.call(args), m[args]](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-12-320.jpg)
![: Lisp-1
• ……
→
→
• Ruby Lisp-2
•
•
Python Ruby
obj.foo(…) obj.foo(…), obj.foo …
( ) obj.foo() obj.foo(), obj.foo
obj.foo obj.method(:foo)
m(…) m.call(…), m[…]](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-13-320.jpg)
![: Chainer
• Chainer
DSL
–
–
type_check.expect(in_types[0].shape == in_types[1].shape)
Expect: in_types[0].shape == in_types[1].shape
Actual: (3,) != (2,)
http://blog.unnono.net/2015/10/chainer-typecheck.html](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-20-320.jpg)
![numpy
• numpy
• numpy
( numpy )
– : x[np.arange(x.shape[0])[:, None], p]
–
•](https://image.slidesharecdn.com/mlxse-20180227-180228032409/85/Python-24-320.jpg)
関数プログラマから見たPythonと機械学習
- 1. Python (2018-02-27) Masahiro Sakai ( ) PYTHON
- 2. • Twitter: @masahiro_sakai github: https://github.com/msakai/ G+: https://plus.google.com/+MasahiroSakai • : ( ) • : – ( Haskell) – –
- 4. • Haskell – Haskell ( ) • Ruby – ( Python ) – Ruby-GNOME2 • Python – Chainer + α – PyPI
- 6. • • • •
- 8. • – R MATLAB • – numpy/scipy, pandas, scikit-learn, matplotlib, Jupyter Notebook, –
- 9. Python • …… Python • ) numpy.array == – numpy … – Python ⇒ – sorted([np.zeros(2), np.zeros(2)]) • ( collections-extended RangeMap )
- 10. : …… • …… • …… • ) pandas itertuples type(next(pd.DataFrame({"x" + str(i): [i] for i in range(253)}).itertuples())) #=> pandas.core.frame.Pandas type(next(pd.DataFrame({"x" + str(i): [i] for i in range(254)}).itertuples())) #=> tuple
- 12. : Lisp-1 • – Scheme, JavaScript – Common Lisp, Ruby Lisp-2 ( ) • Python Ruby obj.foo(args) obj.foo(args) ( ) obj.foo() obj.foo(), obj.foo obj.foo obj.method(:foo) m(args) m.call(args), m[args]
- 13. : Lisp-1 • …… → → • Ruby Lisp-2 • • Python Ruby obj.foo(…) obj.foo(…), obj.foo … ( ) obj.foo() obj.foo(), obj.foo obj.foo obj.method(:foo) m(…) m.call(…), m[…]
- 14. • (PEP 484) • mypy def greeting(name: str) -> str: return 'Hello ' + name print(greeting(0)) # => error: Argument 1 to "greeting" has incompatible type "int"; expected "str"
- 15. • Haskeller – – • – → • Python Haskell – • List Tuple List ……
- 16. • (gradual typing) – (dynamic typing) (static typing) – Jeremy G. Siek and Walid Taha, Gradual Typing for Functional Languages, in Proceedings of the 2006 Scheme and Functional Programming Workshop • – dynamic type: Any … Any – type consistency relation: A B • A = B Any ( : int→Any Any→str) – int ⊑ Any ⊑ str • (1)
- 17. (2) • – Python (mypy), TypeScript, Closure, Hack, Flow, C#? – • Python – • Python (mypy) • …… – (Any ) • e.g. Blame Calculus ( ) • Python (mypy)
- 18. • : • (np.array, chainer.Variable ) ⇒ • shape – shape • ( : forward backward ) (1) def __call__(self, x : np.array) -> np.array:
- 19. • shape Array(m,n,o) …… – reshape ⇒ (c.f. ) – Haskell hmatrix API † …… • (2) † https://hackage.haskell.org/package/hmatrix-0.18.2.0/docs/Numeric-LinearAlgebra-Static.html
- 20. : Chainer • Chainer DSL – – type_check.expect(in_types[0].shape == in_types[1].shape) Expect: in_types[0].shape == in_types[1].shape Actual: (3,) != (2,) http://blog.unnono.net/2015/10/chainer-typecheck.html
- 21. (3) • • … •
- 23. • CPython • GPU CPU – Python …… – NN CPU – GPU ……
- 24. numpy • numpy • numpy ( numpy ) – : x[np.arange(x.shape[0])[:, None], p] – •
- 25. • ( 1 540 2.1GB ) parsy-1.1.0 290m7.032s pyparsing-2.2.0 562m41.623s funcparserlib-0.3.6 79m45.315s megaparsec-5.3.1 (Haskell) 18m12.025s attoparsec-0.13.1.0 (Haskell) 15m46.415s : Python str Haskell ByteString(bytes )
- 27. • – CPython (Go ) • GIL (Global Interpreter Lock) – CPython …… ONNX-Chainer ……
- 29. • Python • Python – – Python •