shawn_leong

shawn_leong

Machine Learning in Elixir: Plot of given `profits` function does not match the expected plot (B1.0, Chapter 3, Page 65)

Hey @seanmor5,

The function given in the book

defn profits(trees) do
  trees
  |> Nx.pow(4)
  |> Nx.negate()
  |> Nx.add(Nx.multiply(2, Nx.pow(trees, 3)))
  |> Nx.add(Nx.pow(trees, 2))
end

Results in the following plot which doesn’t match the expected plot in the book:

The accompanying Livebooks provides the following code to give the expected plot:

defn profits(trees) do
  -((trees - 1) ** 4) + trees ** 3 + trees ** 2
end

So my guess is that there is an error in the conversion to Nx functions.

Instead, the correct translation of the Livebook function should be as follows:

  defn profits(trees) do
    trees
    |> Nx.subtract(1)
    |> Nx.pow(4)
    |> Nx.negate()
    |> Nx.add(Nx.pow(trees, 3))
    |> Nx.add(Nx.pow(trees, 2))
  end
  • Adds the missing Nx.subtract(1) that the book doesn’t have
  • Removes the unnecessary doubling of the cube in Nx.add(Nx.multiply(2, Nx.pow(trees,3)))

This gives the correct expected plot

Marked As Solved

seanmor5

seanmor5

Author of Genetic Algorithms in Elixir

Thank you for pointing this out! I’ve fixed the issue in the next beta release!

Where Next?

Popular Pragmatic Bookshelf topics Top

Alexandr
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...
New
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
gilesdotcodes
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...
New
Chrichton
Dear Sophie. I tried to do the “Authorization” exercise and have two questions: When trying to plug in an email-service, I found the ...
New
leba0495
Hello! Thanks for the great book. I was attempting the Trie (chap 17) exercises and for number 4 the solution provided for the autocorre...
New
adamwoolhether
I’m not quite sure what’s going on here, but I’m unable to have to containers successfully complete the Readiness/Liveness checks. I’m im...
New
AufHe
I’m a newbie to Rails 7 and have hit an issue with the bin/Dev script mentioned on pages 112-113. Iteration A1 - Seeing the list of prod...
New
davetron5000
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New
roadbike
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 ...
New
dachristenson
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...
New

Other popular topics Top

AstonJ
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...
New
New
ohm
Which, if any, games do you play? On what platform? I just bought (and completed) Minecraft Dungeons for my Nintendo Switch. Other than ...
New
wolf4earth
@AstonJ prompted me to open this topic after I mentioned in the lockdown thread how I started to do a lot more for my fitness. https://f...
New
AstonJ
Or looking forward to? :nerd_face:
483 11975 256
New
AstonJ
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting: asdf install erlang 23.1.2 Configure failed. checking ...
New
AstonJ
Saw this on TikTok of all places! :lol: Anyone heard of them before? Lite:
New
Maartz
Hi folks, I don’t know if I saw this here but, here’s a new programming language, called Roc Reminds me a bit of Elm and thus Haskell. ...
New
PragmaticBookshelf
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
CommunityNews
A Brief Review of the Minisforum V3 AMD Tablet. Update: I have created an awesome-minisforum-v3 GitHub repository to list information fo...
New

Sub Categories: