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

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

Docker for Rails Developers: Notes for Rails 6.1, Ruby 2.7.2

I thought that there might be interest in using the book with Rails 6.1 and Ruby 2.7.2. I’ll note what I needed to do differently here. ...

/book-docker-for-rails-developers

9 1177 1

2021-01-03 20:41:43 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

Kotlin and Android Development featuring Jetpack: SwitchCompat's thumbTint and trackTint being ignored (page 76)

I think I might have found a problem involving SwitchCompat, thumbTint, and trackTint. As entered, the SwitchCompat changes color to hol...

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

0 2749 2

2022-05-13 11:00:18 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

Python Testing with pytest, Second Edition: error when running tox in parallel (page 151)

When trying to run tox in parallel as explained on page 151, I got the following error: tox: error: argument -p/–parallel: expected one...

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

0 1111 1

2021-12-10 05:12:17 UTC

New

PragProg Customers

Programming Phoenix LiveView: B6.0 pg 56 - current-user not set

It seems the second code snippet is missing the code to set the current_user: current_user: Accounts.get_user_by_session_token(session["...

#errata /book-programming-phoenix-liveview

0 1898 8

2023-01-11 03:06:26 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 Phoenix LiveView: PentoWeb.LayoutView errata (56)

root_layout: {PentoWeb.LayoutView, :root}, This results in the following following error: no “root” html template defined for PentoWeb...

#errata /book-programming-phoenix-liveview

8 1094 4

2023-10-22 17:25:26 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

Other popular topics

General Dev>Dev Chat

HELLO WORLD (Introductions thread!)

Hello Devtalk World! Please let us know a little about who you are and where you’re from :nerd_face:

#community

481 6762 116

2025-11-06 03:57:03 UTC

New

General Dev>Dev Chat

Standing Desks

No chair. I have a standing desk. This post was split into a dedicated thread from our thread about chairs :slight_smile:

#workspace #opinions

177 9554 77

2022-09-27 18:40:05 UTC

New

General Dev>Hardware

Poll: Which keyboard layout do you use?

poll poll Be sure to check out @Dusty’s article posted here: An Introduction to Alternative Keyboard Layouts It’s one of the best write-...

colemakmods.github.io

#polls /keyboards

10 6048 11

2020-10-31 23:12:33 UTC

New

General Dev>Hardware

Custom keyboard keycaps

There’s a whole world of custom keycaps out there that I didn’t know existed! Check out all of our Keycaps threads here: https://forum....

#hardware /keyboards #keycaps #mechanical-keyboards

15 11086 19

2023-07-27 16:30:57 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

General Dev>Code Editors

Doom-Emacs: Can't find emacs in your PATH

If you get Can't find emacs in your PATH when trying to install Doom Emacs on your Mac you… just… need to install Emacs first! :lol: bre...

#macos /emacs #doom-emacs

4 5837 0

2022-02-04 00:32:03 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

Backend>Learning Resources

Ash Framework

Explore the power of Ash Framework by modeling and building the domain for a real-world web application. Rebecca Le @sevenseacat and ...

pragprog.com

#pragprog /elixir #published-book /ash /book-ash-framework

15 7555 9

2025-02-06 12:19:21 UTC

New

Backend>Learning Resources

MySQL 9 Essentials

A concise guide to MySQL 9 database administration, covering fundamental concepts, techniques, and best practices. Neil Smyth MySQL...

pragprog.com

#pragprog #published-book /mysql /book-mysql-9-essentials

2 4162 0

2025-03-12 13:05:49 UTC

New

AI>Questions

What are the best text-to-speech ai generation tools that you can run locally?

Background Lately I am in a quest to find a good quality TTS ai generation tool to run locally in order to create audio for some videos I...

#ai #text-to-speech

6 8411 3

2025-03-24 16:48:39 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

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

Docker for Rails Developers: Notes for Rails 6.1, Ruby 2.7.2

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

Kotlin and Android Development featuring Jetpack: SwitchCompat's thumbTint and trackTint being ignored (page 76)

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

Python Testing with pytest, Second Edition: error when running tox in parallel (page 151)

Programming Phoenix LiveView: B6.0 pg 56 - current-user not set

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

Programming Phoenix LiveView: PentoWeb.LayoutView errata (56)

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