COMPSs_Manuals/source/Sections/09_PyCOMPSs_Notebooks/hands-on/12_Integral_PI_reduction.ipynb

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   "source": [
    "# Integral PI (with @reduction)\n",
    "\n",
    "## 1.1 Initialize PyCOMPSs"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import pycompss.interactive as ipycompss"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "********************************************************\n",
      "**************** PyCOMPSs Interactive ******************\n",
      "********************************************************\n",
      "*          .-~~-.--.           ______        ______    *\n",
      "*         :         )         |____  \\      /  __  \\   *\n",
      "*   .~ ~ -.\\       /.- ~~ .      __) |      | |  | |   *\n",
      "*   >       `.   .'       <     |__  |      | |  | |   *\n",
      "*  (         .- -.         )   ____) |   _  | |__| |   *\n",
      "*   `- -.-~  `- -'  ~-.- -'   |______/  |_| \\______/   *\n",
      "*     (        :        )           _ _ .-:            *\n",
      "*      ~--.    :    .--~        .-~  .-~  }            *\n",
      "*          ~-.-^-.-~ \\_      .~  .-~   .~              *\n",
      "*                   \\ \\ '     \\ '_ _ -~                *\n",
      "*                    \\`.\\`.    //                      *\n",
      "*           . - ~ ~-.__\\`.\\`-.//                       *\n",
      "*       .-~   . - ~  }~ ~ ~-.~-.                       *\n",
      "*     .' .-~      .-~       :/~-.~-./:                 *\n",
      "*    /_~_ _ . - ~                 ~-.~-._              *\n",
      "*                                     ~-.<             *\n",
      "********************************************************\n",
      "* - Starting COMPSs runtime...                         *\n",
      "* - Log path : /home/user/.COMPSs/Interactive_22/\n",
      "* - PyCOMPSs Runtime started... Have fun!              *\n",
      "********************************************************\n"
     ]
    }
   ],
   "source": [
    "import os\n",
    "if 'BINDER_SERVICE_HOST' in os.environ:\n",
    "    ipycompss.start(graph=True,                # trace=True\n",
    "                   project_xml='../xml/project.xml',\n",
    "                    resources_xml='../xml/resources.xml')\n",
    "else:\n",
    "    ipycompss.start(graph=True, monitor=1000, debug=True)  # trace=True"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 1.2 Required imports"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "from pycompss.api.api import compss_wait_on\n",
    "from pycompss.api.task import task\n",
    "from pycompss.api.reduction import reduction\n",
    "from pycompss.api.parameter import *"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 2 Tasks Declaration"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "@task(returns=float)\n",
    "def calculate_area(i, num_steps, number_of_batches, step_size):\n",
    "    partial_area_sum = 0\n",
    "    for i in range(i, num_steps, number_of_batches):\n",
    "        x = (i+0.5) * step_size\n",
    "        partial_area_sum += 4 / (1 + x**2)\n",
    "    return partial_area_sum"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "![title](pi_resources/pi_integral.png)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "@reduction(chunk_size=\"2\")\n",
    "@task(returns=float, batches_partial_areas=COLLECTION_IN)\n",
    "def sum_reduction(batches_partial_areas):\n",
    "    total_area = 0\n",
    "    for partial_area in batches_partial_areas:\n",
    "        total_area += partial_area\n",
    "    return total_area"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Run the algorithm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "num_steps = 100000\n",
    "number_of_batches = 10"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "step_size = 1 / num_steps"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Task definition detected.\n",
      "Found task: calculate_area\n",
      "Task definition detected.\n",
      "Found task: sum_reduction\n"
     ]
    }
   ],
   "source": [
    "batches_partial_areas = []\n",
    "for i in range(number_of_batches):\n",
    "    partial_area = calculate_area(i, num_steps, number_of_batches, step_size)\n",
    "    batches_partial_areas.append(partial_area)\n",
    "\n",
    "    \n",
    "total_area = sum_reduction(batches_partial_areas)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Wait for all tasks to finish and gather the result"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "total_area = compss_wait_on(total_area)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Calculate PI"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [],
   "source": [
    "pi = step_size * total_area"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "PI: 3.141592653598127 Error: 8.333778112046275e-12\n"
     ]
    }
   ],
   "source": [
    "print('PI:', pi, 'Error:', abs(np.pi-pi))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "scrolled": true
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "********************************************************\n",
      "*************** STOPPING PyCOMPSs ******************\n",
      "********************************************************\n",
      "Checking if any issue happened.\n",
      "Warning: some of the variables used with PyCOMPSs may\n",
      "         have not been brought to the master.\n",
      "********************************************************\n"
     ]
    }
   ],
   "source": [
    "ipycompss.stop()"
   ]
  }
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