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

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

Build Websites with Hugo: Code will not run in a working Hugo setup

Hello Brian, I have some problems with running the code in your book. I like the style of the book very much and I have learnt a lot as...

#question /book-build-websites-with-hugo

0 1501 3

2021-01-29 18:54:24 UTC

New

PragProg Customers

Distributed Services with Go: Chapter 3 suggestions

Page 28: It implements io.ReaderAt on the store type. Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt? ...

#errata /book-distributed-services-with-go

0 1302 3

2022-07-27 14:35:18 UTC

New

PragProg Customers

Modern Front-End Development for Rails: Can't get TURBO_STREAM format in some cases

This isn’t directly about the book contents so maybe not the right forum…but in some of the code apps (e.g. turbo/06) it sends a TURBO_ST...

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

1 1386 7

2021-04-04 21:22:11 UTC

New

PragProg Customers

Intuitive Python: docker run… denied error (page 2)

Title: Intuitive Python: docker run… denied error (page 2) Attempted to run the docker command in both CLI and Powershell PS C:\Users\r...

#errata /book-intuitive-python

9 1263 4

2021-04-06 16:33:24 UTC

New

PragProg Customers

Python Testing with pytest, Second Edition: cards pip install error (page 12)

#book-python-testing-with-pytest-second-edition Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...

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

4 1191 3

2021-07-03 13:40:39 UTC

New

PragProg Customers

Python Testing with pytest, Second Edition: unrecognized arguments error (page 122)

When I run the coverage example to report on missing lines, I get: pytest --cov=cards --report=term-missing ch7 ERROR: usage: pytest [op...

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

0 4000 1

2021-12-03 05:36:38 UTC

New

PragProg Customers

Kotlin and Android Development featuring Jetpack: No activity_main.xml anymore

I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...

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

0 2172 6

2023-08-15 06:19:56 UTC

New

PragProg Customers

Kotlin and Android Development featuring Jetpack: Transformations class doesn't seem to exist anymore (pp. 140-141

@mfazio23 Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...

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

0 2155 5

2023-10-01 15:02:47 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

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>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

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

General Dev>Dev Chat

Languages Without Garbage Collection

Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...

#garbage-collection

21 5575 7

2021-05-06 05:54:58 UTC

New

Community>In The Spotlight

Spotlight: Dmitry Zinoviev (Author) Interview and AMA!

Author Spotlight Dmitry Zinoviev @aqsaqal Today we’re putting our spotlight on Dmitry Zinoviev, author of Data Science Essentials in ...

#author-spotlight /python /book-complex-network-analysis-in-python /book-data-science-essentials-in-python /book-resourceful-code-reuse /book-pythonic-programming

33 5211 14

2022-10-11 20:07:10 UTC

New

Frontend>Chat

Online Hand to eye coordination test

Was just curious to see if any were around, found this one: I got 51/100: Not sure if it was meant to buy I am sure at times the b...

#online-tools

4 4562 1

2022-03-27 10:53:45 UTC

New

Community>In The Spotlight

Spotlight: Jamis Buck (Author) Interview and AMA!

Author Spotlight Jamis Buck @jamis This month, we have the pleasure of spotlighting author Jamis Buck, who has written Mazes for Prog...

#author-spotlight /ruby /book-the-ray-tracer-challenge /book-mazes-for-programmers

21 6352 9

2022-09-28 18:21:15 UTC

New

Game Dev>Questions

Can I use Java to program a game for Nintendo switch?

I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...

/java #nintendo

8 4771 3

2023-09-15 11:15:04 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

AI>Chat

Post your DeepSeek results

Curious what kind of results others are getting, I think actually prefer the 7B model to the 32B model, not only is it faster but the qua...

/deepseek

15 4275 15

2025-03-06 23:29:12 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

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

Build Websites with Hugo: Code will not run in a working Hugo setup

Distributed Services with Go: Chapter 3 suggestions

Modern Front-End Development for Rails: Can't get TURBO_STREAM format in some cases

Intuitive Python: docker run… denied error (page 2)

Python Testing with pytest, Second Edition: cards pip install error (page 12)

Python Testing with pytest, Second Edition: unrecognized arguments error (page 122)

Kotlin and Android Development featuring Jetpack: No activity_main.xml anymore

Kotlin and Android Development featuring Jetpack: Transformations class doesn't seem to exist anymore (pp. 140-141

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

Other popular topics

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

How fast do you type? Check your WPM here!