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
Author of Genetic Algorithms in Elixir
Thank you for pointing this out! I’ve fixed the issue in the next beta release!
1
Popular Pragmatic Bookshelf topics
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...
New
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list)
Typo:...
New
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.
...
New
Hi @Margaret ,
On page VII the book tells us the example and snippets will be all using Elixir version 1.11
But on page 3 almost the en...
New
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...
New
Page 28: It implements io.ReaderAt on the store type.
Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt?
...
New
I’m new to Rust and am using this book to learn more as well as to feed my interest in game dev. I’ve just finished the flappy dragon exa...
New
Hi,
I completed chapter 6 but am getting the following error when running:
thread 'main' panicked at 'Failed to load texture: IoError(O...
New
It seems the second code snippet is missing the code to set the current_user:
current_user: Accounts.get_user_by_session_token(session["...
New
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...
New
Other popular topics
Design and develop sophisticated 2D games that are as much fun to make as they are to play. From particle effects and pathfinding to soci...
New
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...
New
New
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
The V Programming Language
Simple language for building maintainable programs
V is already mentioned couple of times in the forum, but I...
New
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...
New
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
There appears to have been an update that has changed the terminology for what has previously been known as the Taskbar Overflow - this h...
New
I’m able to do the “artistic” part of game-development; character designing/modeling, music, environment modeling, etc.
However, I don’t...
New
A concise guide to MySQL 9 database administration, covering fundamental concepts, techniques, and best practices.
Neil Smyth
MySQL...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /ruby
- /wasm
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /crystal
- /c-plus-plus
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /opensuse
- /html
- /centos
- /php
- /zig
- /deepseek
- /scala
- /lisp
- /sublime-text
- /textmate
- /react-native
- /nixos
- /debian
- /agda
- /kubuntu
- /arch-linux
- /deno
- /django
- /revery
- /nodejs
- /ubuntu
- /spring
- /manjaro
- /diversity
- /lua
- /julia
- /c
- /slackware










