hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

pchiusano

module Window where

import Data.Monoid

data Window a = Window [a] a [a] deriving (Show,Read)

null :: Window a -> Bool
null (Window [] _ []) = True
null _ = False

djspiewak

Introduction to scalaz-stream

Every application ever written can be viewed as some sort of transformation on data. Data can come from different sources, such as a network or a file or user input or the Large Hadron Collider. It can come from many sources all at once to be merged and aggregated in interesting ways, and it can be produced into many different output sinks, such as a network or files or graphical user interfaces. You might produce your output all at once, as a big data dump at the end of the world (right before your program shuts down), or you might produce it more incrementally. Every application fits into this model.

The scalaz-stream project is an attempt to make it easy to construct, test and scale programs that fit within this model (which is to say, everything). It does this by providing an abstraction around a "stream" of data, which is really just this notion of some number of data being sequentially pulled out of some unspecified data source. On top of this abstraction, sca

mpilquist

// Save as ~/.ammonite/predef.sc
// To use fs2 from ammonite repl, type `load.fs2` from repl prompt.
// You'll get all fs2 & cats imports, ContextShift and Timer instances
// for IO, and a globalBlocker

import $plugin.$ivy.`org.typelevel:::kind-projector:0.11.0`

if (!repl.compiler.settings.isScala213)
  repl.load.apply("interp.configureCompiler(_.settings.YpartialUnification.value = true)")

RaasAhsan

import java.util.concurrent.atomic.*;
import java.util.concurrent.*;

public class Main {
    private static ExecutorService executor = Executors.newFixedThreadPool(2);
    private static int iterations = 10000000;
  
    public static class Runner {
        // writes to canceled happen before a CAS on suspended
        // reads on canceled happen after a CAS on suspended

RaasAhsan

object Lambda extends App {
  
  sealed trait Term
  sealed trait Var[I <: Index] extends Term
  sealed trait App[T1 <: Term, T2 <: Term] extends Term
  sealed trait Abs[T1 <: Term] extends Term
  sealed trait If[T1 <: Term, T2 <: Term, T3 <: Term] extends Term
  sealed trait Bool[T1 <: Boolean] extends Term

  sealed trait Index