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Theano: let's build a net

8b502110540ed039608d25f8e227f847?s=47 ktisha
July 03, 2016

Theano: let's build a net

8b502110540ed039608d25f8e227f847?s=128

ktisha

July 03, 2016
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  1. Theano: let’s build a net Ekaterina Tuzova

  2. Motivation

  3. MNIST dataset X — images (60000, 784) Y — labels

    (60000, ) Goal: train a model to look at images and predict what digits they are.
  4. K nearest neighbors

  5. K nearest neighbors ~95 % accuracy

  6. Feature engineering

  7. Machine Learning

  8. Machine Learning

  9. Variable in Computer Science A piece of informations stored somewhere

    in memory with a name made up by a programmer.
  10. Variable in Mathematics Indeterminate quantity that can be manipulated using

    arithmetic operations, or using calculus and so on.
  11. Theano

  12. What is Theano? A library for efficiently handling mathematical expressions

    involving tensors.
  13. What is tensor? Multi-dimensional array.

  14. What is Theano? A mathematical symbolic expression compiler.

  15. Quick How-To - Define symbolic expression - Compile a function

    that can compute numeric values using those expressions - Execute that function on data
  16. Example model GoogLeNet, 2014 ~99.6% accuracy

  17. Logistic regression Probabilistic, linear classifier.

  18. Simple model

  19. Preparation

  20. Load MNIST

  21. Define model

  22. Theano shared variable Shared between different functions and function calls.

  23. Build model

  24. Train model

  25. Train model ~93% accuracy

  26. Simple model

  27. Improve model

  28. Improve model

  29. Improve model

  30. Train model ~98.5% accuracy

  31. Thank you. @ktisha