<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Semi-Gradient TD on Arshad Siddiqui</title><link>https://arshadhs.github.io/tags/semi-gradient-td/</link><description>Recent content in Semi-Gradient TD on Arshad Siddiqui</description><generator>Hugo</generator><language>en-us</language><atom:link href="https://arshadhs.github.io/tags/semi-gradient-td/index.xml" rel="self" type="application/rss+xml"/><item><title>Value-Based DRL: Function Approximation</title><link>https://arshadhs.github.io/docs/ai/045-deep-reinforcement-learning/080-value-based-drl-function-approximation/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://arshadhs.github.io/docs/ai/045-deep-reinforcement-learning/080-value-based-drl-function-approximation/</guid><description>&lt;h1 id="value-based-drl-function-approximation">
 Value-Based DRL: Function Approximation
 
 &lt;a class="anchor" href="#value-based-drl-function-approximation">#&lt;/a>
 
&lt;/h1>
&lt;p>Tabular methods store a separate value for every state or state-action pair. This becomes impractical when the state space is very large, continuous or represented by raw observations. Function approximation replaces this table with a parameterised function that can &lt;strong>learn from observed states, generalise to related states and predict values for states not seen during training&lt;/strong>.&lt;/p>
&lt;p>&lt;strong>Course Content covered in this module:&lt;/strong>&lt;/p>
&lt;ul>
&lt;li>Function approximation&lt;/li>
&lt;li>Feature Construction for Linear Methods:
&lt;ul>
&lt;li>Tile Coding&lt;/li>
&lt;li>Asymmetric Tile Coding&lt;/li>
&lt;/ul>
&lt;/li>
&lt;li>Linear function approximation&lt;/li>
&lt;li>Semi-Gradient TD methods&lt;/li>
&lt;li>Off-policy function approximation and TD divergence&lt;/li>
&lt;li>TD-Gammon&lt;/li>
&lt;/ul>
&lt;span style="color: blue;">
 &lt;strong>Instead of memorising one value per state, the agent learns parameters shared across many states.&lt;/strong>
&lt;/span>
&lt;hr>
&lt;h2 id="learning-objectives">
 Learning Objectives
 
 &lt;a class="anchor" href="#learning-objectives">#&lt;/a>
 
&lt;/h2>
&lt;p>By the end of this module, you should be able to:&lt;/p></description></item></channel></rss>