Thomas ThomasLau

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

Enable native memory tracking in JVM by specifying the following flag

-XX:NativeMemoryTracking=detail

Know the <PID> of the java process

jps

To print ps based RSS

ps -p <PID> -o pcpu,rss,size,vsize

To print native memory tracking summary

Free Monad + Interpreter Pattern

It's like creating the front end and back end of a compiler inside Haskell without the need of Template Haskell!

Write your DSL AST as a Free Monad, and then interpret the monad any way you like.

The advantage is that you get to swap out your interpreter, and your main code

See https://github.com/sbt/sbt/wiki/sbt-1.x-plugin-migration for the list with sbt 1.x migration status.

plugin	star
playframework/playframework	9597
scala-js/scala-js	3053
sbt/sbt-assembly	1092
mpeltonen/sbt-idea	1085

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of


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