fix HW6 gradient of cost equation

rcc02007 · Apr 10, 2017 · ee2c3e2 · ee2c3e2
1 parent 8db16c4
commit ee2c3e2
Show file tree

Hide file tree

Showing 10 changed files with 440 additions and 2 deletions.
diff --git a/HW6/README.md b/HW6/README.md
@@ -34,12 +34,14 @@ variable is failure (1=fail, 0=pass). Create a function called `cost_logistic.m`
 takes the vector `a`, and independent variable `x` and dependent variable `y`. Use the
 function, $\sigma(t)=\frac{1}{1+e^{-t}}$ where $t=a_{0}+a_{1}x$. Use the cost function,
 
-    $J(a_{0},a_{1})=\sum_{i=1}^{n}\left[-y_{i}\log(\sigma(t_{i}))-(1-y_{i})\log((1-\sigma(t_{i})))\right]$
+    $J(a_{0},a_{1})=1/m\sum_{i=1}^{n}\left[-y_{i}\log(\sigma(t_{i}))-(1-y_{i})\log((1-\sigma(t_{i})))\right]$
 
     and gradient
 
    $\frac{\partial J}{\partial a_{i}}=
-   1/m\sum_{k=1}^{N}\left(\sigma(t_{k})-y_{k}\right)t_{k}$
+   1/m\sum_{k=1}^{N}\left(\sigma(t_{k})-y_{k}\right)x_{k}^{i}$
+
+   where $x_{k}^{i} is the k-th value of temperature raised to the i-th power (0, and 1)
 
    a. edit `cost_logistic.m` so that the output is `[J,grad]` or [cost, gradient]
 

diff --git a/lecture_17/octave-workspace b/lecture_17/octave-workspace
diff --git a/lecture_18/octave-workspace b/lecture_18/octave-workspace
diff --git a/lecture_19/octave-workspace b/lecture_19/octave-workspace
diff --git a/lecture_20/octave-workspace b/lecture_20/octave-workspace
diff --git a/lecture_21/.ipynb_checkpoints/lecture_21-checkpoint.ipynb b/lecture_21/.ipynb_checkpoints/lecture_21-checkpoint.ipynb
@@ -0,0 +1,6 @@
+{
+ "cells": [],
+ "metadata": {},
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/lecture_21/lecture_21.ipynb b/lecture_21/lecture_21.ipynb
diff --git a/lecture_21/q1.png b/lecture_21/q1.png
diff --git a/lecture_21/q2.png b/lecture_21/q2.png
diff --git a/lecture_21/reduce_noise.png b/lecture_21/reduce_noise.png