Theano: let's build a net

Transcript

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