kai

Programming Machine Learning:

Programming Machine Learning
From Coding to Deep Learning
German edition

Chapter 11
Training the network
Page 191

def back(X, Y, y_hat, w2, h):
w2_gradient = np.matmul(prepend_bias(h).T, y_hat - Y) / X.shape[0]

 a_gradient = np.matmul(y_hat - Y, w2[1:].T) * sigmoid_gradient(h)
 w1_gradient = np.matmul(prepend_bias(X).T, a_gradient) / X.shape[0]

 return (w1_gradient, w2_gradient)

Hi Paolo,
can you explain me how to come to the decision to multiply this expression:
np.matmul(y_hat - Y, w2[1:].T) * sigmoid_gradient(h)
element by element?

Sincerely,
Kai

4 comments

#question /book-programming-machine-learning

1 553 4

2023-10-03 20:36:18 UTC

Most Liked

kai

As I understand it, there is no recipe to derive compositions of functions, whose inputs are matrices, according to them, as it is the case with a scalar.

Thank you for giving me an answer that helped my understanding anyway.

I am fascinated by mathematics and its power. But to be able to see its beauty, it requires a lot of time. That is why I asked such a question.

Your book was recommended to me and declared very worthwhile, which I can confirm 100%. It is my introduction to ML. Thank you for it!

Translated with DeepL Translate: The world's most accurate translator (free version)

Post #5

Where Next?

View thread on forum

View Programming Machine Learning's book portal

Post errata for this book

Post a suggestion for this book

Post a question about this book

Post a review about this book

question

Home PragProg Customers

#question /book-programming-machine-learning

1 553 4

Last post

Popular Pragmatic Bookshelf topics

PragProg Customers

Python Testing with pytest: pytest now requires markers to be declared (downloadable code)

Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...

#errata /book-python-testing-with-pytest

2 1383 2

2021-02-16 14:15:02 UTC

New

PragProg Customers

Apple Game Frameworks and Technologies: Screen image may be wrong (p 13)

Working through the steps (checking that the Info,plist matches exactly), run the demo game and what appears is grey but does not fill th...

#errata /book-apple-game-frameworks-and-technologies

11 1081 5

2021-05-15 17:31:07 UTC

New

PragProg Customers

The Ray Tracer Challenge: "Computing the normal on a transformed sphere" ebook test

Hi Jamis, I think there’s an issue with a test on chapter 6. I own the ebook, version P1.0 Feb. 2019. This test doesn’t pass for me: ...

#errata /book-the-ray-tracer-challenge

10 1461 5

2025-01-13 14:42:44 UTC

New

PragProg Customers

Programming Phoenix LiveView: errata and remarks Version B2.0

The generated iex result below should list products instead of product for the metadata. (page 67) iex> product = %Product{} %Pento....

#errata /book-programming-phoenix-liveview

0 1800 20

2021-03-23 10:33:03 UTC

New

PragProg Customers

Python Testing with pytest, Second Edition: File not Found Error (page 43)

I ran this command after installing the sample application: $ cards add do something --owner Brian And got a file not found error: Fil...

#errata /book-python-testing-with-pytest-second-edition

5 4391 7

2021-07-03 13:51:08 UTC

New

PragProg Customers

Modern Front-End Development for Rails: ERROR in tsconfig.json Chapter_01/01

@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...

/book-modern-front-end-development-for-rails

3 1438 3

2021-09-02 19:11:59 UTC

New

PragProg Customers

Programming Phoenix LiveView: book not updated to version 1.6 (p. 18)

In general, the book isn’t yet updated for Phoenix version 1.6. On page 18 of the book, the authors indicate that an auto generated of ro...

#errata /book-programming-phoenix-liveview

9 2051 12

2022-02-08 11:31:40 UTC

New

PragProg Customers

Real-Time Phoenix: ProductChannelTest - undefined function describe/2 (pg 203)

Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...

#question /book-real-time-phoenix

0 1775 6

2022-02-16 19:15:15 UTC

New

PragProg Customers

Real-Time Phoenix: use PubSub with implementation of Phoenix.Socket.Transport rather than channels (page 37)

Hi, I’ve got a question about the implementation of PubSub when using a Phoenix.Socket.Transport behaviour rather than channels. Before ...

#question /book-real-time-phoenix #websockets #phoenixsocket #pubsub

0 1528 3

2022-02-28 15:41:06 UTC

New

PragProg Customers

Hands-on Rust: How do I debug a call chain in Rust?

When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...

#question /book-hands-on-rust

2 1034 2

2022-07-14 12:23:33 UTC

New

Other popular topics

Backend>Learning Resources

Web Development with Clojure, Third Edition

Stop developing web apps with yesterday’s tools. Today, developers are increasingly adopting Clojure as a web-development platform. See f...

pragprog.com

#pragprog #web-development /clojure #published-book /book-web-development-with-clojure-third-edition

5 4584 1

2022-01-06 05:27:09 UTC

New

General Dev>Learning Resources

A Common-Sense Guide to Data Structures and Algorithms, Second Edition

Algorithms and data structures are much more than abstract concepts. Mastering them enables you to write code that runs faster and more e...

pragprog.com

#pragprog /python /ruby #published-book /book-a-common-sense-guide-to-data-structures-and-algorithms-second-edition #math #algorithms /js

19 6022 5

2020-08-14 00:58:37 UTC

New

Android>Learning Resources

Kotlin and Android Development featuring Jetpack: Build Better, Safer Android Apps

Start building native Android apps the modern way in Kotlin with Jetpack's expansive set of tools, libraries, and best practices. Learn h...

pragprog.com

#pragprog #android #game-dev /kotlin #published-book /book-kotlin-and-android-development-featuring-jetpack

7 5084 1

2020-11-03 20:38:30 UTC

New

General Dev>Hardware

BIIP MT3 Extended 2048 Custom Keycap Set (Drop)

This looks like a stunning keycap set :orange_heart: A LEGENDARY KEYBOARD LIVES ON When you bought an Apple Macintosh computer in the e...

/keyboards #apple #keycaps #mechanical-keyboards

14 6713 7

2020-12-12 19:58:26 UTC

New

Linux>Questions

What is the most minimalist Linux server distro?

I am asking for any distro that only has the bare-bones to be able to get a shell in the server and then just install the packages as we ...

#linux #servers

66 25846 24

2022-04-13 13:30:03 UTC

New

Backend>Learning Resources

Machine Learning in Elixir

Leverage Elixir and the Nx ecosystem to build intelligent applications that solve real-world problems in computer vision, natural languag...

pragprog.com

#pragprog /elixir #published-book #machine-learning #nx /book-machine-learning-in-elixir

18 4615 7

2024-11-08 22:13:04 UTC

New

Backend>Learning Resources

Server-Driven Web Apps with htmx

Build modern server-driven web applications using htmx. Whatever programming language you use, you’ll write less (and cleaner) code. ...

pragprog.com

#pragprog #web-development #published-book /book-server-driven-web-apps-with-htmx

6 5257 3

2024-06-08 22:37:09 UTC

New

Game Dev>Questions

I want to learn how make a game, but where should I start?

I’m able to do the “artistic” part of game-development; character designing/modeling, music, environment modeling, etc. However, I don’t...

#game-dev

15 4965 9

2025-10-18 13:12:58 UTC

New

Game Dev>Chat

Hair Salon Games for Girls Fun

Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...

#ios #android #unity #fun

2 3556 1

2025-02-27 10:48:33 UTC

New

Backend>Learning Resources

Simplicity

Fight complexity and reclaim the original spirit of agility by learning to simplify how you develop software. The result: a more humane a...

pragprog.com

#pragprog #published-book /book-simplicity

10 6553 8

2025-03-14 21:53:12 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

Python Testing with pytest: pytest now requires markers to be declared (downloadable code)

Apple Game Frameworks and Technologies: Screen image may be wrong (p 13)

The Ray Tracer Challenge: "Computing the normal on a transformed sphere" ebook test

Programming Phoenix LiveView: errata and remarks Version B2.0

Python Testing with pytest, Second Edition: File not Found Error (page 43)

Modern Front-End Development for Rails: ERROR in tsconfig.json Chapter_01/01

Programming Phoenix LiveView: book not updated to version 1.6 (p. 18)

Real-Time Phoenix: ProductChannelTest - undefined function describe/2 (pg 203)

Real-Time Phoenix: use PubSub with implementation of Phoenix.Socket.Transport rather than channels (page 37)

Hands-on Rust: How do I debug a call chain in Rust?

Other popular topics

Web Development with Clojure, Third Edition

A Common-Sense Guide to Data Structures and Algorithms, Second Edition

Kotlin and Android Development featuring Jetpack: Build Better, Safer Android Apps

BIIP MT3 Extended 2048 Custom Keycap Set (Drop)