Spark demo #0 - distribute hard computations.ipynb

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   "source": [
    "import os\n",
    "\n",
    "os.environ[\"PYSPARK_SUBMIT_ARGS\"]='--packages com.databricks:spark-csv_2.10:1.1.0 pyspark-shell'\n",
    "os.environ[\"SPARK_HOME\"]='/home/cheshire/spark/'\n",
    "\n",
    "import sys\n",
    "\n",
    "sys.path.append(os.environ.get('SPARK_HOME', None)+\"/python\")\n",
    "sys.path.append(os.environ.get('SPARK_HOME', None)+\"/python/lib/py4j-0.8.2.1-src.zip\")\n",
    "\n",
    "import py4j\n",
    "from pyspark import SparkContext,SparkConf,SQLContext\n",
    "\n",
    "conf = (SparkConf().setMaster(\"local[2]\")\n",
    "        .setAppName(\"ML demo\")\n",
    "        .set(\"spark.executor.memory\", \"2g\")\n",
    "        .set(\"spark.cores.max\", \"2\"))\n",
    "\n",
    "sc = SparkContext(conf=conf)\n",
    "\n",
    "sqlCtx = SQLContext(sc)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "u'1.5.0'"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "sc.version"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": [
    "params = [(1,5), (3,17), (2,25)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "dataset = range(100000)\n",
    "common_data = sc.broadcast(dataset)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def hard_function((a,b)):\n",
    "    return len( [x for x in common_data.value if x % b == 0] )"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "results = sc.parallelize(params).map(hard_function).collect()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[20000, 5883, 4000]"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "results"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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