{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This notebook documents how to solve the famous [zebra puzzle](http://en.wikipedia.org/wiki/Zebra_puzzle) by A. Einstein with the help of semantic web tools for python.\n",
    "\n",
    "\n",
    "It is based on theses Links/Projects\n",
    "\n",
    "- https://pythonhosted.org/Owlready2/index.html\n",
    "- https://github.com/RDFLib/OWL-RL/issues/3 \"Solving Einstein's riddle (zebra puzzle\"\n",
    "    - Linked owl-files:\n",
    "    - https://github.com/RDFLib/OWL-RL/files/1533408/einsteins_riddle.owl.txt ← works\n",
    "        - created by [D. Ponomaryov](https://persons.iis.nsk.su/en/ponom/ontologies)\n",
    "\n",
    "For installation I did:\n",
    "\n",
    "```bash\n",
    "pip install owlready\n",
    "``` \n",
    "\n",
    "Note there is also https://github.com/RDFLib/OWL-RL/files/1533409/zebra.n3.txt but the N3-Format is not supported by Owlready.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import os\n",
    "import owlready2 as owl2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Solution\n",
    "\n",
    "Assumption: ontology file has been downloaded to `./ontology_data/<filename>`. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "data_path = \"ontology_data\"\n",
    "path1 = os.path.join(data_path, \"einsteins_riddle.owl.txt\")\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "classes (concepts):\n",
      " [owl.Nothing, einsteins_riddle.owl.txt.Beverage, einsteins_riddle.owl.txt.Man, einsteins_riddle.owl.txt.Color, einsteins_riddle.owl.txt.House, einsteins_riddle.owl.txt.Pet, einsteins_riddle.owl.txt.Cigarette] \n",
      "\n",
      "\n",
      "properties (roles):\n",
      " [einsteins_riddle.owl.txt.drinks, einsteins_riddle.owl.txt.has_color, einsteins_riddle.owl.txt.lives_in, einsteins_riddle.owl.txt.owns, einsteins_riddle.owl.txt.right_to, einsteins_riddle.owl.txt.smokes, 1.1.description, 1.1.date, 1.1.creator] \n",
      "\n",
      "\n",
      "individuals:\n",
      " [einsteins_riddle.owl.txt.orange_juice, einsteins_riddle.owl.txt.tea, einsteins_riddle.owl.txt.water, einsteins_riddle.owl.txt.coffee, einsteins_riddle.owl.txt.milk, einsteins_riddle.owl.txt.Kools, einsteins_riddle.owl.txt.Lucky_Strike, einsteins_riddle.owl.txt.Parliaments, einsteins_riddle.owl.txt.Chesterfields, einsteins_riddle.owl.txt.Old_Gold, einsteins_riddle.owl.txt.green, einsteins_riddle.owl.txt.red, einsteins_riddle.owl.txt.blue, einsteins_riddle.owl.txt.yellow, einsteins_riddle.owl.txt.ivory, einsteins_riddle.owl.txt.house_2, einsteins_riddle.owl.txt.house_3, einsteins_riddle.owl.txt.house_1, einsteins_riddle.owl.txt.house_4, einsteins_riddle.owl.txt.house_5, einsteins_riddle.owl.txt.Ukrainian, einsteins_riddle.owl.txt.Spaniard, einsteins_riddle.owl.txt.Norwegian, einsteins_riddle.owl.txt.Englishman, einsteins_riddle.owl.txt.Japanese, einsteins_riddle.owl.txt.zebra, einsteins_riddle.owl.txt.horse, einsteins_riddle.owl.txt.snails, einsteins_riddle.owl.txt.dog, einsteins_riddle.owl.txt.fox]\n"
     ]
    }
   ],
   "source": [
    "# get an overview what is inside the Ontology\n",
    "onto = owl2.get_ontology(path1).load()\n",
    "print(\"classes (concepts):\\n\", list(onto.classes()), \"\\n\"*2)\n",
    "print(\"properties (roles):\\n\", list(onto.properties()), \"\\n\"*2)\n",
    "print(\"individuals:\\n\", list(onto.individuals()))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Relations before calling the reasoner"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[(einsteins_riddle.owl.txt.Norwegian, einsteins_riddle.owl.txt.house_1)]"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(onto.lives_in.get_relations())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[(einsteins_riddle.owl.txt.Spaniard, einsteins_riddle.owl.txt.dog)]"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(onto.owns.get_relations())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Calling the reasoner and inspect relations again"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "CPU times: user 30.8 ms, sys: 4.35 ms, total: 35.2 ms\n",
      "Wall time: 4.68 s\n"
     ]
    }
   ],
   "source": [
    "%time owl2.sync_reasoner_pellet(infer_property_values=True, infer_data_property_values=True, debug=0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[(einsteins_riddle.owl.txt.Norwegian, einsteins_riddle.owl.txt.house_1), (einsteins_riddle.owl.txt.Englishman, einsteins_riddle.owl.txt.house_3), (einsteins_riddle.owl.txt.Japanese, einsteins_riddle.owl.txt.house_5), (einsteins_riddle.owl.txt.Ukrainian, einsteins_riddle.owl.txt.house_2), (einsteins_riddle.owl.txt.Spaniard, einsteins_riddle.owl.txt.house_4)]\n"
     ]
    }
   ],
   "source": [
    "rels = list(onto.lives_in.get_relations())\n",
    "print(rels)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "scrolled": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[(einsteins_riddle.owl.txt.Spaniard, einsteins_riddle.owl.txt.dog), (einsteins_riddle.owl.txt.Englishman, einsteins_riddle.owl.txt.snails), (einsteins_riddle.owl.txt.Japanese, einsteins_riddle.owl.txt.zebra), (einsteins_riddle.owl.txt.Norwegian, einsteins_riddle.owl.txt.fox), (einsteins_riddle.owl.txt.Ukrainian, einsteins_riddle.owl.txt.horse)]\n"
     ]
    }
   ],
   "source": [
    "rels = list(onto.owns.get_relations())\n",
    "print(rels)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "n.Spaniard.owns: n.dog\n",
      "n.Englishman.owns: n.snails\n",
      "n.Japanese.owns: n.zebra\n",
      "n.Norwegian.owns: n.fox\n",
      "n.Ukrainian.owns: n.horse\n"
     ]
    }
   ],
   "source": [
    "for r in rels:\n",
    "    print(f\"n.{r[0].name}.owns: n.{r[1].name}\")\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Conclusion\n",
    "\n",
    "The puzzle could be solved easily by the reasoner\n",
    "\n",
    "---\n",
    "\n",
    "Note: This Puzzle is also an example of [yamlpyowl](https://github.com/cknoll/yamlpyowl) – an experimental package to represent OWL-Ontologies in YAML:\n",
    "\n",
    "<https://github.com/cknoll/yamlpyowl/blob/main/doc/demo_notebooks/zebra_puzzle.ipynb>\n",
    "\n"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.8.6"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}