Skip to Content
ゼロから作るDeep Learning ❹ ―強化学習編
book

ゼロから作るDeep Learning ❹ ―強化学習編

by 斎藤 康毅
April 2022
Intermediate to advanced
376 pages
4h 55m
Japanese
O'Reilly Japan, Inc.
Content preview from ゼロから作るDeep Learning ❹ ―強化学習編

付録D方策勾配法の証明

ここでは「9章 方策勾配法」で使用した数式の証明を行います。

D.1 方策勾配法の導出

9.1 最も単純な方策勾配法」で説明したとおり、J(\theta) = \mathbb{E}_{\tau \sim \pi_{\theta}}[G(\tau)]としたとき、その勾配は次の式(9.1)で表されます。

\nabla_\theta J(\theta) =\mathbb{E}_{\tau \sim \pi_{\theta}}\left[\sum^T_{t=0}   G(\tau) \nabla_\theta \log \pi_{\theta}(A_t| S_t)\right]\tag{9.1}

ここでは、式(9.1)の導出を行います。

まずは記号の確認です。ここでは方策を\pi_{\theta}としたとき、軌道\tauが得られる確率を\Pr(\tau | \theta)で表すことにします。それでは、を数式で順に展開していきます。

数式の右側にあるコメントを参考に1つずつ追ってみましょう。微分についての知識があれば、特に難しい点はないと思います。ここでは1点「 ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

ゼロから作るDeep Learning ❸ ―フレームワーク編

ゼロから作るDeep Learning ❸ ―フレームワーク編

斎藤 康毅

Publisher Resources

ISBN: 9784873119755Other