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lean new neander
cd neander
# change project.clj to include [uncomplicate/neanderthal "0.8.0"]

# this fetches a “atlas-3.10.2” locally
apt-get source atlas
sudo apt-get build-dep atlas
sudo apt-get install devscripts
cd atlas-3.10.2
fakeroot debian/rules custom

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;; The list of (almost) all Clojure public functions and macros ordered by usage. Source: Github code search for Clojure repositories.

(["ns" 394490]
 ["defn" 293918]
 ["require" 279210]
 ["let" 237654]
 ["def" 172983]
 ["refer" 163654]
 ["map" 159781]
 ["fn" 154482]

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(defn count-neighbors [h w x y cells]
  (->> (for [dx [-1 0 1]
             dy [-1 0 1]
             :let [x' (+ x dx)
                   y' (+ y dy)]
             :when (and (not (= dx dy 0))
                        (<= 0 x' (dec w))
                        (<= 0 y' (dec h)))] [x' y'])
       (filter cells)
       count))

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Introduction

I found a link to this now disappeared Clojure wiki page giving a pretty good explanantion of Clojure support for fast-math by Rich. I then found it again at http://clojure.org/old_news and on the original thread on the ML. The document illustrates the rationale behind some early Clojure optimisations that are still integral part of Clojure nowadays. The changes Rich describes here are mainly to enable the JVM JIT inlining of primitive operations and bring Clojure performance on primitive types (including arrays) on par with Java.

Below I also added the related IRC chat with some additional explanation.

You can consider this an extended comment to the work encompassing (roughly) git commit https://github.com/clojure/clojure/commit/5d9e87e8a30dfc99fe41c3be0a8ddc5ddd4e1d8d to

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# List of all the valid pdf URLs ever posted to the #Clojure IRC channel.
#
# Many of them are interesting CS papers others are not that useful. What I've done:
#
# 1. crawled an IRC history archive for the channel
# 2. extract pdf list in a file with: grep -riIohE 'https?://[^[:space:]]+pdf' * > pdf-links.txt
# 3. remove dupes: cat pdf-links.txt | sort | uniq > pdf-links-uniq.txt
# 4. filter only HTTP 200: cat pdf-links-uniq.txt | xargs curl -o /dev/null --connect-timeout 2 --silent --head --write-out '%{http_code} %{url_effective}\n' | grep "^200" > valid-pdf-links.txt
# 
# Now your choice to download them all or not. If you want, use: cat valid-pdf-links.txt | awk '{print $2}' | xargs wget

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;; An implementation of a lazy seq that given a graph in the form of a list
;; of edges (e.g. ["AB" "BC" "CD"] can be de-queued of any number
;; of valid paths (in the above example ["AB" "BC" "CD" "ABC" "BCD"] only). 
;; Returns nils for acyclic graphs after the number of all 
;; available paths have been exhausted. So if you take 100 from the above, 
;; the returned collection will have nils after 5 elements. For cyclic graphs
;; it will follow the cycles infintely. To prevent infinte loops, it will
;; exit after a threshold anyway.
;; The approach is definitely brute-force. Optimisations can be done by 
;; introducing weight for edges and operating on less costly paths first.

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;; with reference to http://www.learningclojure.com/2013/09/efficiency-and-progress-my-god-clojure.html

(ns cljperf.core
  (:use criterium.core))

;; assumptions: we are searching for raw clojure speed for some problem
;; that requires just performances. We can give up some of the Clojure simplicity
;; and expressivness because we connected a profiler and we know what we are doing. 
;; Second: we know how to measure. The time macro is too unreliable at this scale, 
;; we'll use criterium.

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export PROJECT_NAME=$1
export WORKING_DIR=/me/prj/$PROJECT_NAME
cd $WORKING_DIR;
 
# create the session
tmux start-server
tmux new-session -d -s $PROJECT_NAME -n work

# start vim in working dir
tmux select-window -t$PROJECT_NAME:1

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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ant sim ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;   Copyright (c) Rich Hickey. All rights reserved.
;   The use and distribution terms for this software are covered by the
;   Common Public License 1.0 (http://opensource.org/licenses/cpl.php)
;   which can be found in the file CPL.TXT at the root of this distribution.
;   By using this software in any fashion, you are agreeing to be bound by
;   the terms of this license.
;   You must not remove this notice, or any other, from this software.

;As shown in the presentation: http://blip.tv/clojure/clojure-concurrency-819147

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public static boolean isBlank(String str) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return true;
        }
        for (int i = 0; i < strLen; i++) {
            if ((Character.isWhitespace(str.charAt(i)) == false)) {
                return false;
            }
        }