community/aqua/shors.ipynb

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   "source": [
    "# _*Experiment with the Shor's Algorithm in Aqua*_\n",
    "\n",
    "This notebook demonstrates how to experiment with the `Shor`'s algorithm in `Qiskit Aqua`.\n",
    "\n",
    "We first import all necessary modules."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "from qiskit import BasicAer\n",
    "from qiskit.aqua import QuantumInstance\n",
    "from qiskit.aqua import run_algorithm\n",
    "from qiskit.aqua.algorithms import Shor"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The [Shor's Factoring Algorithm](https://en.wikipedia.org/wiki/Shor's_algorithm) is explained in more detail in the corresponding notebook located in the directory `community/algorithms`. With Aqua, we can create a `Shor` instance by simply providing the target integer to be factored and run it, as follows."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "The list of factors of 15 as computed by the Shor's algorithm is [3, 5].\n"
     ]
    }
   ],
   "source": [
    "N = 15\n",
    "shor = Shor(N)\n",
    "backend = BasicAer.get_backend('qasm_simulator')\n",
    "quantum_instance = QuantumInstance(backend, shots=1024)\n",
    "ret = shor.run(quantum_instance)\n",
    "print(\"The list of factors of {} as computed by the Shor's algorithm is {}.\".format(N, ret['factors'][0]))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The above step-by-step programatic approach can also be achieved by using a json configuration dictionary with the parameters for the algorithm and any other dependent objects it requires, as follows:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "scrolled": true
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The list of factors of 15 as computed by the Shor's algorithm is [3, 5].\n"
     ]
    }
   ],
   "source": [
    "params = {\n",
    "    'problem': {\n",
    "        'name': 'factoring',\n",
    "    },\n",
    "    'algorithm': {\n",
    "        'name': 'Shor',\n",
    "        'N': N,\n",
    "    },\n",
    "    'backend': {\n",
    "        'shots': 1024,\n",
    "    },\n",
    "}\n",
    "result_dict = run_algorithm(params, backend=backend)\n",
    "print(\"The list of factors of {} as computed by the Shor's algorithm is {}.\".format(N, result_dict['factors'][0]))"
   ]
  }
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