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===Linear Regression===
===Linear Regression===
Assume we have a dataset:
Assume we have a dataset:<br>
<math>\{(x_i, y_i)\}_{i=1}^{n}</math>   
<math>\{(x_i, y_i)\}_{i=1}^{n}</math>   
<math>y_i \in \mathbb{R}</math>
<math>y_i \in \mathbb{R}</math><br>
<math>x_i \in \mathbb{R}^d</math>
<math>x_i \in \mathbb{R}^d</math><br>
<math>f(w, x) = w^t x</math>
<math>f(w, x) = w^t x</math>


<math>L(w) = \frac{1}{2} \sum_{i=1}^{n}(y_i - f(w, x_i))^2</math>
<math>L(w) = \frac{1}{2} \sum_{i=1}^{n}(y_i - f(w, x_i))^2</math><br>
<math>\min_{W} L(w)</math>
<math>\min_{W} L(w)</math><br>
GD: <math>w(t+1) = w(t) - \eta_{t} \nabla L(w_t)</math> where our gradient is:
GD: <math>w(t+1) = w(t) - \eta_{t} \nabla L(w_t)</math> where our gradient is:<br>
<math>\sum_{i=1}^{n}(y_i - f(w, x_i)) \nabla_{w} f(w_t, x_i) = \sum_{i=1}^{n}(y_i - f(w, x_i)) x_i</math>
<math>\sum_{i=1}^{n}(y_i - f(w, x_i)) \nabla_{w} f(w_t, x_i) = \sum_{i=1}^{n}(y_i - f(w, x_i)) x_i</math>