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 1341 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 1341 4
Last post

Popular Pragmatic Bookshelf topics Top

johnp
PragProg Customers

Python Testing with pytest - Chapter 5 example c AttributeError: 'module' object has no attribute 'config'
Running the examples in chapter 5 c under pytest 5.4.1 causes an AttributeError: ‘module’ object has no attribute ‘config’. In particula...
#errata/book-python-testing-with-pytest
5 3582 1
New
jesse050717
PragProg Customers

Web Development with Clojure, Third Edition: Issue adding Shadow CLJS
Title: Web Development with Clojure, Third Edition, pg 116 Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...
#question/book-web-development-with-clojure-third-edition
4 1199 4
New
yulkin
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
New
lirux
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
New
AleksandrKudashkin
PragProg Customers

Modern Front-End Development for Rails: B7 no main folder in the source code (page xv)
On the page xv there is an instruction to run bin/setup from the main folder. I downloaded the source code today (12/03/21) and can’t see...
#errata/book-modern-front-end-development-for-rails
2 1452 11
New
gilesdotcodes
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
New
curtosis
PragProg Customers

Build a Weather Station with Elixir and Nerves: 'mix deps.get' does not work if user has not created a keyfile (page 16)
Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
#errata/book-build-a-weather-station-with-elixir-and-nerves
2 1457 3
New
hazardco
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
New
akraut
PragProg Customers

Programming Phoenix LiveView: Display Image Uploads (pdf p142)
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error. lib/pento_web/live/product_l...
#errata/book-programming-phoenix-liveview
2 2102 9
New
s2k
PragProg Customers

Agile Web Development with Rails 7: Reloading assets in development mode
Hi all, currently I wonder how the Tailwind colours work (or don’t work). For example, in app/views/layouts/application.html.erb I have...
#question/book-agile-web-development-with-rails-7
2 1380 4
New

Other popular topics Top

PragmaticBookshelf
Game Dev>Learning Resources

The Ray Tracer Challenge
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
pragprog.com
#pragprog#published-book/book-the-ray-tracer-challenge#algorithms
3 6115 0
New
siddhant3030
General Dev>Dev Chat

Which vertical monitor do you use?
I’m thinking of buying a monitor that I can rotate to use as a vertical monitor? Also, I want to know if someone is using it for program...
#monitors#programming
51 4892 20
New
DevotionGeo
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
New
dimitarvp
macOS>Chat

My thoughts on macOS vs Linux
Small essay with thoughts on macOS vs. Linux: I know @Exadra37 is just waiting around the corner to scream at me “I TOLD YOU SO!!!” but I...
#macos#linux
166 9730 69
New
AstonJ
General Dev>Dev Chat

Languages Without Garbage Collection
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
#garbage-collection
21 5575 7
New
Margaret
General Dev>Dev Chat

PragProg’s Medium Posts
Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.
#pragprog#blog-post
1147 29994 760
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 5051 11
New
PragmaticBookshelf
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
New
AstonJ
Backend>Questions

Psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such file or directory
If you’re getting errors like this: psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
#macos/rails/postgresql
1 5553 1
New
mindriot
General Dev>Reviews

Keyboard Review: UHK60V2 vs Defy vs Voyager vs Glove80 vs Svalboard
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
/keyboards#uhk60v2#defy#voyager#glove80#svalboard
5 5681 7
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.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

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!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

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.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

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!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap