Kornel’s gists

Kornel / norm-vs-beta.ipynb

Created September 23, 2016 19:51

Normal vs Beta approximation

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Kornel / mc_de_moivre.R

Last active September 14, 2016 09:29

Plotting "the most dangerous equation in the world": http://press.princeton.edu/chapters/s8863.pdf. Monte Carlo test how the standard deviation changes with respect to the sample size.


	split.into.intervals <- function(what, interval.count = NULL, interval.size = NULL) {

	if (sum(sapply(list(interval.count, interval.size), is.null)) != 1)
	stop("exactly one of 'interval.count', 'interval.size', must be NULL")

	if (!is.null(interval.count))
	n <- length(what) / interval.count
	else
	n <- interval.size

Kornel / mc_norm_diff.R

Created September 12, 2016 08:29

Monte Carlo verification of two Normal Distributions difference

	mean.a <- runif(1, min = -10, max = 10)
	mean.b <- runif(1, min = -10, max = 10)
	sd.a <- runif(1, min = 1, max = 10)
	sd.b <- runif(1, min = 1, max = 10)

	x <- seq(from = min(mean.a, mean.b) - 4 * max(sd.a, sd.b),
	to = max(mean.a, mean.b) + 4 * max(sd.a, sd.b),
	by = 0.1)

	a <- dnorm(x, mean = mean.a, sd = sd.a)

Kornel / randomwalk.R

Created September 11, 2016 17:11

Random walk in R

	library(ggplot2)

	walk <- function(N, p = 0.5) {
	cumsum((-1)^rbinom(N, 1, 1 - p))
	}

	# Convergence of the random walk
	l <- sapply(1:1000, function(n){
	N <- 100
	tail(walk(N, 0.5), 1)

Kornel / push-and-pr.sh

Last active September 30, 2016 07:50

Push to bitbucket (stash) and create pull-request

	#!/bin/sh
	REMOTE_BRANCH=$1
	if [[ -z "${REMOTE_BRANCH}" ]]
	then
	REMOTE_BRANCH="develop"
	fi

	USER=`whoami`
	PROJECT=`git remote -v \| grep push \| awk -F"/" ' { print $4 } '`
	REPO=`git remote -v \| grep push \| awk -F"/" ' { print $5 } ' \| sed 's/\.git.*//'`

Kornel / decision-boundaries.Rmd

Created March 25, 2016 11:00

Decision boundaries for a MLP, SVM and a Random Forest

	---
	title: "Decision boundaries"
	author: "Kornel Kiełczewski"
	date: "25 March 2016"
	output: html_document
	---

	Decision boundaries for a somewhat biased test case :)

	```{r, echo=FALSE, message=FALSE, warning=FALSE}

Kornel / nnet-decision-boundary.R

Created March 25, 2016 09:50

Decision boundary for MLP

	set.seed(1)
	pts <- seq(0, 360, 10)

	x1 <- c(sapply(pts, function(x) cos(x)),
	sapply(pts, function(x) cos(x) * 4),
	sapply(pts, function(x) cos(x) * 6))

	x2 <- c(sapply(pts, function(x) sin(x)),
	sapply(pts, function(x) sin(x) * 4),
	sapply(pts, function(x) sin(x) * 6))

Kornel / nnet-decision-boundary.R

Created March 24, 2016 18:19

Decision boundary nnet

	library(nnet)

	n <- 20
	x1 <- rnorm(n)
	x2 <- rnorm(n)
	y <- as.factor(rbinom(n, 1, 0.5))

	data <- data.frame(x1, x2, y)

	fit <- nnet(y ~ ., data, size = 10)

Kornel / pull-all.sh

Created February 12, 2016 08:28

Pull all git subdirectories - if successful, be quiet.

	#!/usr/bin/env bash


	quiet_git() {
	tempfile=`mktemp /tmp/git-pull-all-XXXXXXXX`
	stdout=$tempfile
	stderr=$tempfile

	if ! git "$@" </dev/null >$stdout 2>$stderr; then
	cat $stderr >&2

Kornel / recursive-cowsay.sh

Last active February 4, 2016 14:18

Recursive cowsay inception - random cow at every step

	#!/usr/bin/env bash

	COWS_PATH="/usr/local/share/cows"

	COW_FILES=($(ls $COWS_PATH))
	COWS=${#COW_FILES[@]}

	rand_cow() {
	#RAND_IDX=$(($RANDOM % $COWS))
	RAND_IDX=$((`od -vAn -N4 -tu4 < /dev/urandom` % $COWS))

Kornel Kiełczewski Kornel