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

Web Development with Clojure, Third Edition: migrations/create not working: p159

Title: Web Development with Clojure, Third Edition - migrations/create not working: p159 When I execute the command: user=> (create-...

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

5 1084 2

2020-11-14 22:24:32 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

The Cucumber for Java Book:

Hello! On page xix of the preface, it says there is a community forum "… for help if your’re stuck on one of the exercises in this book… ...

#question /book-the-cucumber-for-java-book

3 1143 1

2021-01-12 18:03:10 UTC

New

PragProg Customers

Web Development with Clojure, Third Edition (vB17.0): create table syntax invalid

Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...

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

0 1835 1

2021-08-13 23:56:52 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: Error in generated Game.java (page 136)

I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...

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

2 1172 8

2021-09-17 18:06:54 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

Agile Web Development with Rails 7: Example code does not work delete method (page 78)

On page 78 the following code appears: <%= link_to ‘Destroy’, product, class: ‘hover:underline’, method: :delete, data: { confirm...

#suggestion /book-agile-web-development-with-rails-7

1 1266 2

2022-01-29 08:01:09 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

Other popular topics

General Dev>Learning Resources

Seven More Languages in Seven Weeks

Learn from the award-winning programming series that inspired the Elixir language, and go on a step-by-step journey through the most impo...

pragprog.com

#pragprog /elixir /julia /lua #published-book #factor /elm #minikanren /idris /book-seven-more-languages-in-seven-weeks

4 5862 0

2020-04-29 21:59:54 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>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

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

Linux>Chat

RancherOS is in end of life

Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...

#linux #rancheros

10 6358 6

2021-01-30 21:04:03 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

General Dev>Questions

Do you prefer regular mechanical keyboards or low profile mechanical keyboards and why?

I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...

/keyboards #mechanical-keyboards

27 3877 9

2023-02-06 21:10:15 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

Android>Questions

Unresolved Reference to android in build.gradle.kts – Beginner Issue

Hello, I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...

#binding

0 7460 2

2024-12-09 21:07:33 UTC

New

Backend>Learning Resources

Advanced Functional Programming with Elixir

Use advanced functional programming principles, practical Domain-Driven Design techniques, and production-ready Elixir code to build scal...

joekoski.com

#pragprog /elixir #published-book #functional-programming /book-advanced-functional-programming-with-elixir

43 4989 22

2025-10-06 09:04:44 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)

Web Development with Clojure, Third Edition: migrations/create not working: p159