Lecture 6-1 Softmax classification:

Multinomial classification

Sung Kim <hunkim+mr@gmail.com>

Logistic regression

Logistic regression

Logistic regression

Logistic regression

Logistic regression

Multinomial classification

x1 (hours) x2 (attendance) y (grade)

10 5 A

9 5 A

3 2 B

2 4 B

11 1 C

Multinomial classification

Multinomial classification

Multinomial classification

Multinomial classification

Multinomial classification

Multinomial classification

Matrix multiplication

https://www.mathsisfun.com/algebra/matrix-multiplying.html

Multinomial classification

Multinomial classification

Where is sigmoid?

Lecture 6-2 Softmax classification:

softmax and cost function

Sung Kim <hunkim+mr@gmail.com>

Where is sigmoid?

Where is sigmoid?

Sigmoid?

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811817

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811817

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811817

Cost function

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811817

Cross-entropy cost function

Cross-entropy cost function

Cross-entropy cost function

Logistic cost VS cross entropy

cost(H(x), y) = ylog(H(x))� (1� y)log(1�H(x)) c

Cost function

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811817

https://www.udacity.com/course/viewer#!/c-ud730/l-6370362152/m-6379811827

Gradient descent

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