inreoh
Genetic Algorithms in Elixir: wrong syntax in ch. 4, termination criteria for one_max ?
@seanmor5
In chapter 4 of p1.0 (page 89 of 262 in the epub version), the code for the avg termination criterion looks like this:
def terminate?(population) do
avg =
population
|> Enum.map(&(Enum.sum(&1) / length(&1)))
avg == 21
end
For me, this causes a syntax error:
protocol Enumerable not implemented for %Types.Chromosome
Presumably because the call to fitness_function() is missing. This version works for me:
avg =
population
|> Enum.map(&OneMax.fitness_function/1)
|> Enum.sum()
|> (fn x -> x / length(population) end).()
although it’s not very elegant (esp. the last line looks ugly), so I’d much prefer something closer to the original version.
Popular Pragmatic Bookshelf topics
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks”
While running the smoke tests in Chapter 2, I get these...
New
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list)
Typo:...
New
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...
New
The generated iex result below should list products instead of product for the metadata. (page 67)
iex> product = %Product{}
%Pento....
New
Title: Web Development with Clojure, Third Edition, vB17.0 (p9)
The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
This is as much a suggestion as a question, as a note for others.
Locally the SGP30 wasn’t available, so I ordered a SGP40. On page 53, ...
New
When running tox for the first time, I got the following error:
ERROR: InterpreterNotFound: python3.10
I realised that I was running ...
New
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
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...
New
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
Other popular topics
Algorithms and data structures are much more than abstract concepts. Mastering them enables you to write code that runs faster and more e...
New
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...
New
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
Bought the Moonlander mechanical keyboard. Cherry Brown MX switches. Arms and wrists have been hurting enough that it’s time I did someth...
New
Build highly interactive applications without ever leaving Elixir, the way the experts do. Let LiveView take care of performance, scalabi...
New
Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.
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
Author Spotlight
Jamis Buck
@jamis
This month, we have the pleasure of spotlighting author Jamis Buck, who has written Mazes for Prog...
New
Author Spotlight:
Peter Ullrich
@PJUllrich
Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
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...
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
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /centos
- /php
- /deepseek
- /zig
- /scala
- /sublime-text
- /textmate
- /lisp
- /react-native
- /debian
- /nixos
- /agda
- /kubuntu
- /django
- /arch-linux
- /deno
- /nodejs
- /revery
- /ubuntu
- /manjaro
- /spring
- /diversity
- /lua
- /julia
- /markdown
- /c








