oskarth

// Concurrency in Go
// ----------------------------------------------------------------
// several processes running at the same time
// dealing with lots of things at once (connections, computations)
// long live Murphy's^H^H^H^H^H^H^HMoore's law!

// Three things: execution, syncing/messaging and control flow

// 1) GOROUTINES          
// ----------------------------------------------------------------                                               

oskarth

ml gives computers ability to learn without being explicitly programmed.

# Linear Regression
linear regression is a simple model to find best for for data.
http://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Linear_regression.svg/400px-Linear_regression.svg.png
view above x and y axis as features, generalize to n-dimensional.

# Example
You have a data set with commute and sleep time, salary and happiness (1-10)
for the three features, commute, sleep and salary you want to predict happy

oskarth

Machine learning gives computers the ability to learn without being explicitly programmed.

Linear Regression

Linear regression is a simple model to find best fit for some data.

Example: You have a data set with commute time, sleep time, salary and happiness (1-10). For the three features - commute time, sleep time and salary - you want to predict happiness level.

Cost function and finding a good fit

How well does this line predict the data? Cost function (essentially sum of deltas between a line at a point and the real point) which we want to minimize. Once function converges we know we have a good fit. How do we find it? Gradient descent.

oskarth

(ns chipper.core
  (:use [clojure.contrib.combinatorics :only (selections)])
  (:use [clojure.pprint :only (pprint)])
  (:require [clojure.tools.macro :as macro]))

(defn bool-space
  "Generates every possible boolean n-tuple."
  [n]
  (selections [0 1] n))

oskarth

(defn- arrow?
  "predicate that returns true if x is =>"
  [x]
  (and (symbol? x) (= (name x) "=>")))

(defn- split-body
  "splits expression into two parts, one with input
   pins and the other with => and outputs"
  [body]
  (split-with (complement arrow?) body))

oskarth

;; nand* is not defined in terms of other gates
;; read the source to find out how we deal with that

(defgate not* [in] => [out]
  (nand* [in in] => [out]))

(defgate and* [a b] => [out]
  (nand* [a b] => [w])
  (not* [w] => [out]))

oskarth

(defn nand* [a b]
  (let [[out] (if (= 2 (+ a b)) [0] [1])
    out))

(defn not* [in]
  (let [[out] (nand* in in)]
    out))

(defn and* [a b]
  (let [[w] (nand* a b)

oskarth

;; using reflex clojurescript library

;; works
(def a (atom 0))
(def b (computed-observable (inc @a)))
(def c (computed-observable (dec @a)))
(def d (computed-observable (str @b)))

;; doesn't 
;; maximum call stack exceeded

oskarth

$ znc --version
ZNC 0.206+deb1 - http://znc.in
$ which znc
/usr/local/bin/znc
$ /usr/local/bin/znc --version
ZNC 1.1-git-20121207-8ffab186 - http://znc.in
IPv6: yes, SSL: yes, DNS: threads

oskarth

#lang r5rs

;; chapter 3 minikanren

(define-syntax var
  (syntax-rules ()
    ((_ x) (vector x))))

(define-syntax var?  (syntax-rules ()
    ((_ x) (vector? x))))