Skip to content

Latest commit

 

History

History
56 lines (29 loc) · 1.38 KB

cs229_gmm.md

File metadata and controls

56 lines (29 loc) · 1.38 KB

KMeans

Gaussina Mixture Model (Density Estimation)

Consider a task from IOT sensor data :

1D example

ALgorithm - warm up

EM Algorithm

(ML 16.6) Gaussian mixture model (Mixture of Gaussians)

we re-format the $p(x)$

$$ p(x) = \sum_{k=1}^{m} \alpha_{k} N(x | \mu_{k}, C_{{k}}) $$

where $k={1, 2, ..., .}$ means $k^{th}$ gaussian dist, $\mu_{k}, C_{k}$ holds mean and std of $k^{th}$ gaussian parameters.

parameters :

$\Theta = (\alpha_{k}, \mu_{k}, C_{k})$ for $k = {1, 2, ..., \m}$

Expectation steps (guess, instead of single value, you guess the whole universe)

maximization : MLE by your guessing, get a modification by bayesian rule.

Ref

cs229 2018

(ML 16.6) Gaussian mixture model (Mixture of Gaussians)

EM_algo from note

最大期望算法