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

Distributed Services With Go - gogoproto on linux

page 20: … protoc command… I had to additionally run the following go get commands in order to be able to compile protobuf code using go...

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

14 2953 7

2020-10-16 05:21:10 UTC

New

PragProg Customers

Programming Machine Learning: Incorrect formula

Hi everyone! There is an error on the page 71 in the book “Programming machine learning from coding to depp learning” P. Perrotta. You c...

#errata /book-programming-machine-learning

5 1341 4

2022-04-06 12:03:54 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

Programming Phoenix LiveView: Typo

Hi! I know not the intentions behind this narrative when called, on page XI: mount() |> handle_event() |> render() but the correc...

#errata /book-programming-phoenix-liveview

3 1307 17

2021-03-11 16:34:20 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: error when installing editable package (page 178)

When installing Cards as an editable package, I get the following error: ERROR: File “setup.py” not found. Directory cannot be installe...

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

0 1739 1

2021-12-10 05:12:55 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

Real Time Phoenix Errata P17: Getting first sample working with Phoenix 1.6.x

Skimming ahead, much of the following is explained in Chapter 3, but new readers (like me!) will hit a roadblock in Chapter 2 with their ...

#errata /book-real-time-phoenix

6 1116 5

2022-12-08 12:49:23 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: End Ch. 11 app runs but consistently crashes

I’ve got to the end of Ch. 11, and the app runs, with all tabs displaying what they should – at first. After switching around between St...

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

0 936 8

2024-01-05 05:43:55 UTC

New

Other popular topics

General Dev>Hardware

Which keyboard do you have?

If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...

#hardware /keyboards #sticky #mechanical-keyboards

144 9115 50

2021-01-07 23:58:36 UTC

New

Backend>Learning Resources

Programming Machine Learning

Machine learning can be intimidating, with its reliance on math and algorithms that most programmers don't encounter in their regular wor...

pragprog.com

#pragprog #ai /python #published-book /book-programming-machine-learning #math #algorithms

6 5350 3

2023-10-03 15:08:13 UTC

New

Linux>Questions

AMD or Intel for Programming with Linux as the OS?

I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...

#mobile #android #web-development #linux #desktop-computer #mobile-development

36 6006 10

2020-07-12 20:50:05 UTC

New

Backend>Questions

Can someone explain the -t option/flag in docker run command?

I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...

#docker

7 10261 2

2020-09-01 07:19:16 UTC

New

General Dev>Code Editors

Onivim 2 Code Editor

Thanks to @foxtrottwist’s and @Tomas’s posts in this thread: Poll: Which code editor do you use? I bought Onivim! :nerd_face: https://on...

#code-editors /onivim /revery

88 6144 32

2023-05-15 07:32:26 UTC

New

General Dev>Hardware

GMK Serika Keycaps - Serika 2 available to order now!

I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...

/keyboards #keycaps #mechanical-keyboards

9 5097 7

2020-12-05 21:32:30 UTC

New

Backend>Learning Resources

Programming Phoenix LiveView

Build highly interactive applications without ever leaving Elixir, the way the experts do. Let LiveView take care of performance, scalabi...

pragprog.com

#pragprog /elixir /phoenix #published-book /book-programming-phoenix-liveview

79 10732 24

2026-02-13 05:37:02 UTC

New

Backend>Learning Resources

Effective Haskell

Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...

pragprog.com

#pragprog /haskell #published-book /book-effective-haskell

15 10218 1

2022-02-16 10:09:51 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

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

Distributed Services With Go - gogoproto on linux

Programming Machine Learning: Incorrect formula