Kamil Slowikowski slowkow

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(The below text is licensed with CC0, which means that if you want to use or translate it, that is OK by me.)

Ok, I geeked out, and this is probably more information than you need. But it completely answers the question. Sorry. ☺

Locally, I'm at this commit:

$ git show
commit d6cd1e2bd19e03a81132a23b2025920577f84e37
Author: jnthn <jnthn@jnthn.net>

Date: Sun Apr 15 16:35:03 2012 +0200

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

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

	// Ported from Stefan Gustavson's java implementation
	// http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
	// Read Stefan's excellent paper for details on how this code works.
	//
	// Sean McCullough banksean@gmail.com

	/**
	* You can pass in a random number generator object if you like.
	* It is assumed to have a random() method.
	*/

	ks.default <- function(rows) seq(2, max(3, rows %/% 4))

	many_kmeans <- function(x, ks = ks.default(nrow(x)), ...) {
	ldply(seq_along(ks), function(i) {
	cl <- kmeans(x, centers = ks[i], ...)
	data.frame(obs = seq_len(nrow(x)), i = i, k = ks[i], cluster = cl$cluster)
	})
	}

	all_hclust <- function(x, ks = ks.default(nrow(x)), point.dist = "euclidean", cluster.dist = "ward") {

	# Get StackOverflow data
	get.stack<-function(tok) {
	# Must check for XML install, thanks onertipaday!
	if (!require(XML)) install.packages('XML')
	library(XML)
	# Enter a SO tag as character string, and number of tags are returned
	tok<-gsub("(/\| )","-",tok)
	tok<-gsub("#","%23",tok,fixed=TRUE)
	base.stack<-"http://stackoverflow.com/questions/tagged/"
	stack.tree<-htmlTreeParse(paste(base.stack,tok,sep=""),useInternalNodes=TRUE)

	#!/bin/bash
	#
	# Watch current directory (recursively) for file changes, and execute
	# a command when a file or directory is created, modified or deleted.
	#
	# Written by: Senko Rasic <senko.rasic@dobarkod.hr>
	#
	# Requires Linux, bash and inotifywait (from inotify-tools package).
	#
	# To avoid executing the command multiple times when a sequence of

	function mycd()
	{
	#if this directory is writable then write to directory-based history file
	#otherwise write history in the usual home-based history file
	tmpDir=$PWD
	echo "#"`date '+%s'` >> $HISTFILE
	echo $USER' has exited '$PWD' for '$@ >> $HISTFILE
	builtin cd "$@" # do actual cd
	if [ -w $PWD ]; then export HISTFILE="$PWD/.dir_bash_history"; touch $HISTFILE; chmod --silent 777 $HISTFILE;
	else export HISTFILE="$HOME/.bash_history";

	#cython: boundscheck=False, wraparound=False
	import numpy as np
	cimport numpy as np

	from cython.parallel cimport prange

	def dot(np.ndarray[np.float32_t, ndim=2] a not None,
	np.ndarray[np.float32_t, ndim=2] b not None,
	np.ndarray[np.float32_t, ndim=2] out=None):
	"""Naive O(N**3) 2D np.dot() implementation."""