When To Use Elixir’s String.to_atom/1

TL;DR: Use String.to_atom/1 at compile time only. In the Erlang VM, atoms are not garbage-collected. Because of that, unchecked creation of atoms can lead to memory leaks at best, and a crashed VM at worse. This has been widely discussed on the internet. Both String.to_atom/1 and the :"string" expression generate arbitrary atoms from strings. Using these two techniques for converting a string to an atom can lead to the above-mentioned problem.

Visualizing Neuron Weights During Training

I have a deep interest in knowing exactly how a neural network works. Not only do I want to know the theory, I want to know– in practice– what’s happening to the neuron’s weights as the network is being trained. With TensorFlow, it took a lot of work and investigation to finally get to a point where I had something that visualized weights being trained. It seemed that TensorFlow was putting roadblocks at every possible path to getting the valuees of the changing weights.

TensorFlow on MacOS

I was very excited to start running TensorFlow Python programs on my Mac. I installed it using PIP, using the instructions provided by TensorFlow.org. On running my first TensorFlow program, the first thing it output was: 2018-11-25 19:13:07.524017: I tensorflow/core/platform/cpu_feature_guard.cc:141] Your CPU supports instructions that this TensorFlow binary was not compiled to use: SSE4.1 SSE4.2 AVX AVX2 FMA This didn’t look good, it turned out it’s just a warning. My program worked, but wasn’t running as fast as it could.

Atom Editor Setup for Elixir

When working with Elixir, I want the following support from my editor: Elixir syntax highlighting Compiler errors and warnings displayed while I’m editing Elixir code Automatic Elixir code formatting Automatic Dialyzer checking and reporting when I save an Elixir code file These are the following plugins that provide those features: language-elixir ide-elixir atom-elixir-formatter linter-elixir-credo Before installing any of these packages, read their README pages carefully.

Elixir Abstract Syntax

As developers know, program source code is represented as lines of text. The Abstract Syntax Tree (AST) is the representation of the source code as a hierarchical data graph, specifically a tree structure. With an AST, much of the difficult work parsing the original source code has been performed, and the syntax can be introspected programatically. Similar to an AST, the Abstract Semantic Graph (ASG) is a graph of the semantic representation of the source code.

Install Redis on macOS with Homebrew

Install brew update brew install redis Upgrade If Redis is already installed, you might want to upgrade: brew upgrade redis Verify Check to see if Redis is already running: redis-cli If it’s already running, you can probably stop here. Launch on System Boot Check to see if it is already set up to launch on boot: ls -l ~/Library/LaunchAgents | grep -i redis Make it launch on boot:

Install Elixir on macOS Using ASDF

Install asdf git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.3.0 echo -e '\n. $HOME/.asdf/asdf.sh' >> ~/.bash_profile echo -e '\n. $HOME/.asdf/completions/asdf.bash' >> ~/.bash_profile . ~/.bash_profile Install Erlang and Elixir Plugins asdf plugin-add erlang https://github.com/asdf-vm/asdf-erlang.git asdf plugin-add elixir https://github.com/asdf-vm/asdf-elixir.git Uninstall Erlang and Elixir managed by Brew brew uninstall --force erlang brew uninstall --force elixir Install Erlang Check what versions of Erlang are available: asdf list-all erlang Install and Use Erlang:

Low-Level ActiveRecord

With many Rails projects, there is occasionally a need to bypass the normal ActiveRecord API, and get closer to the low-level SQL API. Here are a few useful methods that bypass the confines of everyday ActiveRecord. #find_by_sql users = User.find_by_sql("SELECT * FROM users WHERE id = 1") This returns model instances for the given SQL string. #find_by_sql also accepts parametrized values, like this: users = User.find_by_sql(["SELECT * FROM users WHERE id = ?

Finding the source for a given Rails web page

These tips may help those of you who are relatively new to Rails, or maybe even if you’re not. Common tips and tricks Look at the URL path (e.g. /users/100685/edit). Can the action and main view file be determined from CRUD/REST conventions? /:model/edit -> edit.html.slim /:model/1234 -> show.html.slim /:model/new -> new.html.slim /:model -> index.html.slim Look up the path in routes.rb, or even more useful, run rake routes Finding a controller and action responsible for a given page In development go to your server’s output, and clear the screen (Ctrl+L, for Linux, Cmd-K for OS X) Refresh the web page Back to the server’s output, scroll to the top of the output.

Considering a switch to the Atom Text Editor?

You’ve probably heard of Atom, Github’s new text editor. Read these checklists to help you decide whether it’s an editor worth switching to. General Pros Open Source High-quality extension and enhancement infrastructure View is programmable using good old HTML DOM and CSS Well-known API model (NodeJS) Built-in Github integration Built-in, light Git integration Realtime Markdown preview Seamlessly tracks external file renames while the file is open Browse archive files, like zip or tar.