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

Hands-On Rust: Wrong multiplier for 8x8 console in main.rs

Title: Hands-On Rust (Chap 8 (Adding a Heads Up Display) It looks like .with_simple_console_no_bg(SCREEN_WIDTH*2, SCREEN_HEIGHT*2...

#errata /book-hands-on-rust

9 2026 5

2022-02-15 14:09:12 UTC

New

PragProg Customers

Hands-on Rust: can_place logic is "inside out"

Title: Hands-On Rust (Chapter 11: prefab) Just played a couple of amulet-less games. With a bit of debugging, I believe that your can_p...

#errata /book-hands-on-rust

22 1628 20

2022-03-29 12:23:50 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 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

Modern CSS with Tailwind: setting up Rails app

In case this helps anyone, I’ve had issues setting up the rails source code. Here were the solutions: In Gemfile, change gem 'rails' t...

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

3 1278 2

2022-01-05 00:19:21 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

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

Modern front-end development for Rails, second edition - Struggling to get the first chapter to work

After running /bin/setup, the first error was: The foreman' command exists in these Ruby versions: That was easy to fix: gem install fore...

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

1 1116 3

2023-06-22 14:09:32 UTC

New

PragProg Customers

Docker for Rails Developers - 'docker-machine' command deprecated (page 156)

Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...

/book-docker-for-rails-developers #suggestion

0 896 0

2023-03-06 18:01:33 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 dev-related stuff have you been up to?

Reading something? Working on something? Planning something? Changing jobs even!? If you’re up for sharing, please let us know what you’...

#community

1063 24245 395

2026-08-08 06:01:03 UTC

New

Hybrid>Learning Resources

Programming Flutter

Instantly view the changes you make to an app with stateful hot reload, and define a declarative UI in the same language as the app logic...

pragprog.com

#pragprog /book-programming-flutter #published-book /flutter

11 4501 1

2020-06-08 20:47:21 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

Game Dev>Learning Resources

Hands-on Rust: Effective Learning through 2D Game Development and Play

Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...

pragprog.com

#pragprog /rust #published-book /book-hands-on-rust

117 10879 30

2024-11-09 13:24:20 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

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

AI>In The News

How to fix the eyes in AI-generated images

aidemos.info

0 4508 0

2022-09-10 13:54:33 UTC

New

General Dev>In The News

Zig now has built-in HTTP server and client in std

zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig. General-purpose programming language and toolchain for maintaini...

github.com

/zig #http

0 5624 0

2023-05-19 00:35:41 UTC

New

Backend>Learning Resources

C Brain Teasers

25 puzzles that will make you a better C programmer by challenging your knowledge of the language, and explaining the technical details o...

pragprog.com

#pragprog #published-book /c /book-c-brain-teasers

4 3873 2

2023-09-27 11:46:41 UTC

New

Programming Machine Learning:

kai

Programming Machine Learning:

Most Liked

kai

Where Next?

Popular Pragmatic Bookshelf topics

Hands-On Rust: Wrong multiplier for 8x8 console in main.rs

Hands-on Rust: can_place logic is "inside out"

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

Programming Phoenix LiveView: errata and remarks Version B2.0

Modern CSS with Tailwind: setting up Rails app

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

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

Modern front-end development for Rails, second edition - Struggling to get the first chapter to work

Docker for Rails Developers - 'docker-machine' command deprecated (page 156)

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

Other popular topics