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

Web Development with Clojure, Third Edition: Issue adding Shadow CLJS

Title: Web Development with Clojure, Third Edition, pg 116 Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...

#question /book-web-development-with-clojure-third-edition

4 1199 4

2021-01-10 05:30:17 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

Programming Phoenix LiveView: P27, live_path confusion

I am working on the “Your Turn” for chapter one and building out the restart button talked about on page 27. It recommends looking into ...

#question /book-programming-phoenix-liveview

7 3505 14

2023-08-09 13:36:28 UTC

New

PragProg Customers

Distributed Services with Go: receiving Unknown flag: --go_opt when compiling protobuf (page 20)

When trying to generate the protobuf .go file, I receive this error: Unknown flag: --go_opt libprotoc 3.12.3 MacOS 11.3.1 Googling ...

/book-distributed-services-with-go

0 4924 3

2021-08-18 18:19:51 UTC

New

PragProg Customers

Kotlin and Android Development featuring Jetpack: $kotlin_version ? (page 8)

I’m running Android Studio “Arctic Fox” 2020.3.1 Patch 2, and I’m embarrassed to admit that I only made it to page 8 before running into ...

#errata /book-kotlin-and-android-development-featuring-jetpack

0 1698 3

2021-09-03 21:44:18 UTC

New

PragProg Customers

Kotlin and Android Development featuring Jetpack: android:tint vs app:tint (chapter 7, p186)

I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint. How to replicate: load chapter-7 from zipfile i...

#errata /book-kotlin-and-android-development-featuring-jetpack

0 3566 3

2022-04-26 09:10:52 UTC

New

PragProg Customers

Hands-on Rust: Failed to Load Texture error (page 121)

Hi, I completed chapter 6 but am getting the following error when running: thread 'main' panicked at 'Failed to load texture: IoError(O...

/book-hands-on-rust

2 1310 3

2022-01-23 22:36:50 UTC

New

PragProg Customers

iOS Unit Testing by Example: 54 Don't seem to be getting the print out on tests (Xcode 13.2)

Hey there, I’m enjoying this book and have learned a few things alredayd. However, in Chapter 4 I believe we are meant to see the “>...

#question /book-ios-unit-testing-by-example

0 1963 3

2022-01-24 15:18:41 UTC

New

PragProg Customers

The Definitive ANTLR 4 Reference - "Java.g4" grammer (used on page 40) no longer passes ANTLR

@parrt In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....

#errata /book-the-definitive-antlr-4-reference

0 1020 3

2023-02-14 01:34:49 UTC

New

PragProg Customers

Programming Machine Learning: Setting up your system (p 13)

From page 13: On Python 3.7, you can install the libraries with pip by running these commands inside a Python venv using Visual Studio ...

#question /book-programming-machine-learning

1 989 3

2023-10-09 07:44:15 UTC

New

Other popular topics

General Dev>Hardware

Which keyboard do you have?

If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...

#hardware /keyboards #sticky #mechanical-keyboards

144 9115 50

2021-01-07 23:58:36 UTC

New

Backend>Learning Resources

Seven Languages in Seven Weeks

Ruby, Io, Prolog, Scala, Erlang, Clojure, Haskell. With Seven Languages in Seven Weeks, by Bruce A. Tate, you’ll go beyond the syntax—and...

pragprog.com

#pragprog /clojure /erlang /haskell /prolog /ruby /scala #published-book /book-seven-languages-in-seven-weeks

5 5730 1

2022-01-20 13:48:55 UTC

New

Backend>Chat

What is the reason behind Rust’s web framework, Rocket, not performing as well as expected in the Techempower benchmarks?

I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...

#web-frameworks /rust

36 7463 11

2020-06-21 10:50:02 UTC

New

General Dev>Dev Chat

How fast do you type? Check your WPM here!

Do the test and post your score :nerd_face: :keyboard: If possible, please add info such as the keyboard you’re using, the layout (Qw...

typing-speed-test.aoeu.eu

/keyboards

82 7682 31

2021-07-10 05:52:20 UTC

New

Backend>Chat

Rails console using 100% CPU in dev (fix)

If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...

/ruby /rails

3 4188 3

2021-02-04 07:08:45 UTC

New

General Dev>Dev Chat

PragProg’s Medium Posts

Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.

#pragprog #blog-post

1147 29994 760

2025-07-10 13:36:16 UTC

New

Backend>Learning Resources

Programming WebRTC

Use WebRTC to build web applications that stream media and data in real time directly from one user to another, all in the browser. ...

pragprog.com

#pragprog #published-book /js #webrtc /book-programming-webrtc

27 6969 6

2021-11-20 19:03:04 UTC

New

Backend>Learning Resources

Programming Ruby 3.2 (5th Edition)

Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...

twitter.com

#pragprog /ruby /rails #published-book /book-programming-ruby-3-2-5th-edition

28 8550 13

2024-11-17 04:34:14 UTC

New

General Dev>In The News

Jan: An open source alternative to ChatGPT that runs on the desktop

Jan | Rethink the Computer. Jan turns your computer into an AI machine by running LLMs locally on your computer. It’s a privacy-focus, l...

jan.ai

#desktop #chatgpt

4 5652 4

2024-03-29 08:42:30 UTC

New

AI>Chat

How to: Run DeepSeek on Mac, Windows, and Linux!

This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...

#macs /deepseek #guides #lm-studio

14 9328 10

2025-06-19 15:11:16 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

Web Development with Clojure, Third Edition: Issue adding Shadow CLJS

Programming Phoenix LiveView: errata and remarks Version B2.0

Programming Phoenix LiveView: P27, live_path confusion

Distributed Services with Go: receiving Unknown flag: --go_opt when compiling protobuf (page 20)

Kotlin and Android Development featuring Jetpack: $kotlin_version ? (page 8)

Kotlin and Android Development featuring Jetpack: android:tint vs app:tint (chapter 7, p186)

Hands-on Rust: Failed to Load Texture error (page 121)

iOS Unit Testing by Example: 54 Don't seem to be getting the print out on tests (Xcode 13.2)

The Definitive ANTLR 4 Reference - "Java.g4" grammer (used on page 40) no longer passes ANTLR

Programming Machine Learning: Setting up your system (p 13)