claj’s gists

claj / example.clj

Last active August 29, 2015 14:05

Steam-roller function

	(steam-roller [:a {1 2 3 4} 1 1 :a :a])
	-> ([:a {1 2, 3 4} 1 1 :a :a] :a {1 2, 3 4} 1 3 2 4 1 1 :a :a)
	count: 11

	;;identityHashCodes:
	(map #(System/identityHashCode %) (steam-roller [:a {1 2 3 4} 1 1 :a :a]))
	(1460028191
	2005509007
	1545655515
	504432400

claj / clojurerng.clj

Created May 12, 2014 19:58

Testing RNG

	(ns clojurerng.core
	(:import [com.modp.random LinearSunJDK])
	(:use [ criterium.core]))

	(def ^:LinearSunJDK linsun (LinearSunJDK.))

	;;this is salvaged from
	;; javarng.googlecode.com/svn/trunk/com/modp/random/LinearSunJDK.java
	;;and the openJDK source code for .nextDouble

claj / enlive_vs_unicode.clj

Last active January 1, 2016 09:49

Enlive with special unicode characters - it's possible

	;;create a lein new something
	;;add [enlive "1.1.5"] to project.clj
	;;lein repl:

	(use 'net.cgrand.enlive-html)

	;;define a simple template "inline"
	(deftemplate abc
	(java.io.StringReader.
	"<html>

claj / countertest.clj

Created September 26, 2013 08:47

Testing performance on clojure atom vs java.util.concurrent.atomic.AtomicInteger counters.

	(ns countertest)

	(set warn-on-reflection true)

	(def atom-cnt (atom 0))

	(time (dotimes [_ 1e6] (swap! atom-cnt inc)))
	;; 156 ms

	(def ^java.util.concurrent.atomic.AtomicInteger atomic-integer-counter (java.util.concurrent.atomic.AtomicInteger. 0))

claj / kibit-arithmetic-rules.clj

Created September 11, 2013 16:57

Some rules I've found useful in Kibit.

	;;trivial identites
	[(+ ?x 0) ?x]
	[(- ?x 0) ?x]
	[(* ?x 1) ?x]
	[(/ ?x 1) ?x]
	[(* ?x 0) 0]

	;;Math/pow
	[(* ?x ?x) (Math/pow ?x 2) ]
	[(* ?x ?x ?x) (Math/pow ?x 3) ]

claj / heatmapfromarray.clj

Last active December 22, 2015 11:09

John Szakmeister asked for a way to show matrixes in the Incanter google group. I gave a bad suggestion wrapping it in a function, which is to complicated things severly. Here's a modified version of incanter.chart/heat-map* which eats a vector-of-vectors of data and a nil-value. https://groups.google.com/forum/#!topic/incanter/spyQuB5c87k The d…

	;;This is released under EPL (same as Clojure) and is most
	;;welcomed to be included to Incanter or anything else
	;;after some bettering (it would be nice to be able
	;;to push DefaultXYZDatasets into the heat-map-thing
	;;instead of function + xy-box

	(ns heatmapfromarray
	"show an vector-of-vectors without missing important parts of it"
	(use [incanter core charts]))

claj / bpm.clj

Last active December 20, 2015 21:09

Find BPM by tapping. Belongs to this blog post: http://multimethods.blogspot.se/2013/08/small-app-for-finding-bpms-by-key-tap.html

	(use 'seesaw.core)

	;; the state, when was the last keypress?
	(def last-tap (atom nil))

	(defn nanoseconds-diff-to-bpm [now then]
	(let [nanosecs-in-a-minute (* 60 1000 1000 1000.0)
	diff (- now then)]
	(/ nanosecs-in-a-minute diff)))

claj / async-math.clj

Last active December 19, 2015 15:19

	(ns async-math)

	(require '[clojure.core.async :as async :refer :all])

	(defn query-maker
	"generates a simple math-query and the answer to it"
	[]
	(let [a (rand-int 10) b (rand-int 10)]
	{:query (str "what is " a " + " b "?")
	:answer (+ a b)}))

claj / testblog.clj

Created July 11, 2013 12:21

Testing embedding GIST in my blog

	(use 'hello)
	(println "hello world!")

claj / no-cardinality-stacktrace

Created October 22, 2012 15:02

When transcating a datomic attribute without cardinality attribute the following stacktrace occurs

	java.util.concurrent.ExecutionException: java.lang.Error: Assert failed: (every? identity [key vtypeid cardinality])
	at datomic.common$throw_executionexception_if_throwable.invoke (common.clj:381)
	datomic.common$promise$reify__253.get (common.clj:423)
	datomic.common$promise$reify__253.deref (common.clj:431)
	clojure.core$deref.invoke (core.clj:2117)
	datomic.peer.Connection.transact (peer.clj:106)
	datomic.api$transact.invoke (api.clj:63)
	datest.core$eval935.invoke (NO_SOURCE_FILE:1)
	clojure.lang.Compiler.eval (Compiler.java:6603)
	clojure.lang.Compiler.eval (Compiler.java:6566)

Linus Ericsson claj