PragProg Customers

Programming Machine Learning: Incorrect formula

Alexandr

Alexandr

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 can’t just change the weighted sum to a sigmoid without first taking the derivative of the sigmoid. See the explanation there https://yadi.sk/i/T75bWimUYPAe7Q

Best regards.

4 comments
#errata/book-programming-machine-learning
5 1335 4

Marked As Solved

nusco

nusco

Author of Metaprogramming Ruby & Programming Machine Learning

Hey, Alexandr! Thank you for taking the time to report this, and even take a picture of your notes!

I kinda regret not putting that calculation in the book, because from the explanation I wrote, it looks like the derivative of the sigmoid just disappeared. Actually, the formula in the book does take that derivative into account. The sigmoid isn’t explicit in the final formula, but it’s baked into the values of y-hat.

It’s been a while since I went through the steps myself, but I googled for a step-by-step calculation and found this one: https://medium.com/analytics-vidhya/derivative-of-log-loss-function-for-logistic-regression-9b832f025c2d

My apologies for not writing the steps by hand (busy day!), but I checked the calculation in the link above, and I cannot see any obvious errors. If you do, can you please point them out?

1
Post #2

Also Liked

Alexandr

Alexandr

Thank you!
I just read it inattentively. I think it would be a good idea to insert that link (https://medium.com/analytics-vidhya/derivative-of-log-loss-function-for-logistic-regression-9b832f025c2d) in the book.
Best regards.
P.S.
Thank you! I think you’ve written the best book for beginners( I’ve read a lot of them).

1
Post #3
nusco

nusco

Author of Metaprogramming Ruby & Programming Machine Learning

No problem, Alexandr, and thank you for reporting the issue anyway!

1
Post #4

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
Home PragProg Customers
#errata/book-programming-machine-learning
5 1335 4
Last post

Popular Pragmatic Bookshelf topics Top

edruder
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 1175 1
New
raul
PragProg Customers

Distributed Services with Go: Chapter 1 Suggestions
Hi Travis! Thank you for the cool book! :slight_smile: I made a list of issues and thought I could post them chapter by chapter. I’m rev...
#errata/book-distributed-services-with-go
2 1179 3
New
leba0495
PragProg Customers

A Common-Sense Guide to Data Structures and Algorithms, Second Edition: (pg460)
Hello! Thanks for the great book. I was attempting the Trie (chap 17) exercises and for number 4 the solution provided for the autocorre...
#errata/book-a-common-sense-guide-to-data-structures-and-algorithms-second-edition
0 1152 3
New
jskubick
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 2702 2
New
jskubick
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 1166 8
New
dsmith42
PragProg Customers

iOS Unit Testing by Example: 54 Don't seem to be getting the print out on tests (Xcode 13.2)
Hey there, I’m enjoying this book and have learned a few things alredayd. However, in Chapter 4 I believe we are meant to see the “>...
#question/book-ios-unit-testing-by-example
0 1947 3
New
kolossal
PragProg Customers

Hands on Rust: Need help with error - thread 'main' panicked at 'Failed to load texture
Hi, I need some help, I’m new to rust and was learning through your book. but I got stuck at the last stage of distribution. Whenever I t...
#question/book-hands-on-rust
3 1979 5
New
Keton
PragProg Customers

Hands-on Rust: How do I debug a call chain in Rust?
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
#question/book-hands-on-rust
2 1027 2
New
mcpierce
PragProg Customers

Kotlin and Android Development featuring Jetpack: Unique constraint error when running chapter 5 code changes
@mfazio23 I’ve applied the changes from Chapter 5 of the book and everything builds correctly and runs. But, when I try to start a game,...
/book-kotlin-and-android-development-featuring-jetpack
0 1165 10
New
dachristenson
PragProg Customers

Kotlin and Android Development featuring Jetpack: No activity_main.xml anymore
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 2120 6
New

Other popular topics Top

DevotionGeo
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 7115 11
New
AstonJ
General Dev>Code Editors

SpaceVim vs SpaceMacs
SpaceVim seems to be gaining in features and popularity and I just wondered how it compares with SpaceMacs in 2020 - anyone have any thou...
/vim#spacevim#spacemacs/emacs#code-editors
30 3990 14
New
Exadra37
Linux>Questions

What is the most minimalist Linux server distro?
I am asking for any distro that only has the bare-bones to be able to get a shell in the server and then just install the packages as we ...
#linux#servers
66 23964 24
New
mafinar
Community>Journals

Programming Crystal Book Club
Crystal recently reached version 1. I had been following it for awhile but never got to really learn it. Most languages I picked up out o...
/crystal/book-programming-crystal#book-club
155 4581 65
New
AstonJ
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 5350 0
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Erin Dees (Author) Interview and AMA!
Author Spotlight Erin Dees @undees Welcome to our new author spotlight! We had the pleasure of chatting with Erin Dees, co-author of ...
#author-spotlight/ruby/rails/book-effective-testing-with-rspec-3/book-seven-more-languages-in-seven-weeks/book-cucumber-recipes#rspec
24 3863 11
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: VM Brasseur (Author) Interview and AMA!
Author Spotlight: VM Brasseur @vmbrasseur We have a treat for you today! We turn the spotlight onto Open Source as we sit down with V...
#author-spotlight/book-forge-your-future-with-open-source
16 4431 11
New
DevotionGeo
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 3339 9
New
PragmaticBookshelf
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 5191 9
New
NewsBot
Backend>Official News

Node.js v22.14.0 released!
Node.js v22.14.0 has been released. Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
github.com
/nodejs#official-news
0 2585 0
New
Back to top

Latest in Programming Machine Learning

Programming Machine Learning Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap