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

The Definitive ANTLR 4 Reference: Program deprecation warning

page 37 ANTLRInputStream input = new ANTLRInputStream(is); as of ANTLR 4 .8 should be: CharStream stream = CharStreams.fromStream(i...

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

4 987 0

2020-07-05 23:04:12 UTC

New

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 Flutter: Image.toByteData() does not exist (page40)

your book suggests to use Image.toByteData() to convert image to bytes, however I get the following error: "the getter ‘toByteData’ isn’t...

/book-programming-flutter #question

1 4102 2

2021-02-23 16:03:08 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

Modern CSS with Tailwind: can’t setup the Rails source code

I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps. With: ruby-3.0.0 s...

#question /book-modern-css-with-tailwind

0 1280 3

2021-03-27 15:29:34 UTC

New

PragProg Customers

Programming Kotlin: Difference between SupervisorJob() and supervisorScope (324, 325)

Hi @venkats, It has been mentioned in the description of ‘Supervisory Job’ title that 2 things as mentioned below result in the same eff...

#question /book-programming-kotlin

0 2242 2

2021-03-16 11:28:51 UTC

New

PragProg Customers

Domain Modeling Made Functional: Missing diagram on page 18

The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...

#errata /book-domain-modeling-made-functional

1 1078 1

2021-09-11 17:34:22 UTC

New

PragProg Customers

Build a Weather Station with Elixir and Nerves: 'mix deps.get' does not work if user has not created a keyfile (page 16)

Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...

#errata /book-build-a-weather-station-with-elixir-and-nerves

2 1457 3

2024-12-18 18:02:25 UTC

New

PragProg Customers

Kotlin and Android Development featuring Jetpack: error concerning function getCurrentStandings in BaseballDao.java

@mfazio23 I’m following the indications of the book and arriver ad chapter 10, but the app cannot be compiled due to an error in the Bas...

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

1 3397 6

2022-07-22 14:06:06 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>Dev Chat

What are you listening to?

A thread that every forum needs! Simply post a link to a track on YouTube (or SoundCloud or Vimeo amongst others!) on a separate line an...

#community #music

202 5126 102

2025-07-26 22:00:31 UTC

New

General Dev>Learning Resources

Forge Your Future with Open Source

Free and open source software is the default choice for the technologies that run our world, and it’s built and maintained by people like...

pragprog.com

#pragprog #published-book /book-forge-your-future-with-open-source

3 5654 0

2020-04-21 18:37:36 UTC

New

Science/Tech>Tech Chat

What are you watching?

Or looking forward to? :nerd_face:

#community

498 13326 269

2026-01-28 02:22:15 UTC

New

Game Dev>Learning Resources

Apple Game Frameworks and Technologies

Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...

pragprog.com

#pragprog #ios #game-dev #macos /swift #published-book #apple /book-apple-game-frameworks-and-technologies

30 7995 10

2021-04-22 16:51:02 UTC

New

General Dev>Code Editors

Poll: Which code editor do you use?

You might be thinking we should just ask who’s not using VSCode :joy: however there are some new additions in the space that might give V...

#community #polls /vim /emacs #code-editors /vscode #notepad /sublime-text #atom /textmate #codespaces #brackets /onivim #geany

121 5796 61

2025-09-05 00:52:19 UTC

New

General Dev>Hardware

Seen any cool new keyboards?

We have a thread about the keyboards we have, but what about nice keyboards we come across that we want? If you have seen any that look n...

/keyboards #mechanical-keyboards

49 5910 39

2025-05-10 22:54:44 UTC

New

General Dev>Hardware

Planck vs Preonic vs Subatomic (Keyboards)

I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...

/keyboards #mechanical-keyboards #ortholinear #planck #preonic

105 17596 47

2021-05-28 21:32:35 UTC

New

Backend>Chat

How to install Ruby 3 with ASDF

In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first: asdf plugin-upd...

/ruby #asdf

11 5961 4

2021-02-02 08:02:13 UTC

New

Backend>Chat

Data Structures and Algorithms with Elixir

This is going to be a long an frequently posted thread. While talking to a friend of mine who has taken data structure and algorithm cou...

/elixir #algorithms #data-structures

108 11869 31

2024-11-14 02:14:00 UTC

New

Community>In The Spotlight

Spotlight: Bruce Tate (Author) Interview and AMA!

Author Spotlight: Bruce Tate @redrapids Programming languages always emerge out of need, and if that’s not always true, they’re defin...

/elixir /ruby /phoenix /book-seven-more-languages-in-seven-weeks /book-seven-languages-in-seven-weeks #liveview /book-programming-phoenix-liveview

54 5678 23

2023-10-17 17:14:03 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

The Definitive ANTLR 4 Reference: Program deprecation warning

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

Programming Flutter: Image.toByteData() does not exist (page40)

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

Modern CSS with Tailwind: can’t setup the Rails source code

Programming Kotlin: Difference between SupervisorJob() and supervisorScope (324, 325)

Domain Modeling Made Functional: Missing diagram on page 18

Build a Weather Station with Elixir and Nerves: 'mix deps.get' does not work if user has not created a keyfile (page 16)

Kotlin and Android Development featuring Jetpack: error concerning function getCurrentStandings in BaseballDao.java

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