{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "PXZouNKCnTLM"
   },
   "source": [
    "# SNT - TP Python 1 : Modélisation d'un réseau social"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "P7klja9m0LqK"
   },
   "source": [
    "<img src=\"https://www.4stars.it/blog/wp-content/uploads/2019/07/lavoro-su-i-social.jpg\" alt=\"Kitten\" title=\"social network\" />"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Za4SNnD02VP3"
   },
   "source": [
    "Pour commencer, exécutez le script suivant pour importer deux modules qui nous seront nécessaires pendant tout le TP."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "nwDAFtmp2DAG"
   },
   "outputs": [],
   "source": [
    "# importation du module \"matplotlib\" pour créer des graphiques\n",
    "import matplotlib.pyplot as plt\n",
    "# importation du module \"networkx\" pour simuler un réseau social\n",
    "import networkx as nx"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "3nPzAzNinfKM"
   },
   "source": [
    "## 1 Introduction"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "J67N7uX9nwxw"
   },
   "source": [
    "Exécuter plusieurs fois le script Python ci-dessous (sans chercher pour le moment à en comprendre le code) :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "fkztyiGsl9hh"
   },
   "outputs": [],
   "source": [
    "#import warnings\n",
    "G = nx.random_geometric_graph(200, 0.125)\n",
    "pos = nx.get_node_attributes(G, 'pos')\n",
    "dmin = 1\n",
    "ncenter = 0\n",
    "for n in pos:\n",
    "    x, y = pos[n]\n",
    "    d = (x - 0.5)**2 + (y - 0.5)**2\n",
    "    if d < dmin:\n",
    "        ncenter = n\n",
    "        dmin = d\n",
    "\n",
    "plt.clf()\n",
    "#with warnings.catch_warnings(record=True):\n",
    "p = dict(nx.single_source_shortest_path_length(G, ncenter))\n",
    "plt.figure(figsize=(8, 8))\n",
    "nx.draw_networkx_edges(G, pos, nodelist=[ncenter], alpha=0.4)\n",
    "nx.draw_networkx_nodes(G, pos, nodelist=list(p.keys()),\n",
    "                        node_size=80,\n",
    "                        node_color=list(p.values()),\n",
    "                        cmap=plt.cm.Reds_r)\n",
    "\n",
    "plt.xlim(-0.05, 1.05)\n",
    "plt.ylim(-0.05, 1.05)\n",
    "plt.axis('off')\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "JrDg5CSYn7Qk"
   },
   "source": [
    "**Exercice 1** : Expliquer pourquoi la figure générée nous permet de modéliser un réseau social."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Dv3CQXuaoLjx"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "dkxZQkV4qEKZ"
   },
   "source": [
    "## 2 Découverte du module networkx"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "CdbhEd5nwTfC"
   },
   "source": [
    "Simulons un réseau social avec le module Python `networkx`.\n",
    "\n",
    "Lire puis exécuter plusieurs fois le code suivant :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "DCosSw2DqWQQ"
   },
   "outputs": [],
   "source": [
    "# création d'un graphe vide non orienté appelé \"monReseau\"\n",
    "monReseau = nx.Graph()\n",
    "\n",
    "monReseau.add_node(\"Audrey\")\n",
    "monReseau.add_node(\"Nicolas\")\n",
    "monReseau.add_node(\"Alexis\")\n",
    "monReseau.add_node(\"Hélène\")\n",
    "\n",
    "plt.clf()\n",
    "# dessine (draw) et affiche (show) le graphe \"monReseau\"\n",
    "nx.draw(monReseau, with_labels=True)\n",
    "plt.show()\n",
    "\n",
    "print(\"Nombre de personnes =\", monReseau.number_of_nodes())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "pQi47nXvxG31"
   },
   "source": [
    "**Exercice 2** : Que fait le code de la ligne 6 : `monReseau.add_node(\"Alexis\")` ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "0l_L3Ij4wwAm"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "nbP5UDKaypo5"
   },
   "source": [
    "Lire puis exécuter plusieurs fois le code suivant :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "ImUlXBDzw1EH"
   },
   "outputs": [],
   "source": [
    "plt.clf()\n",
    "\n",
    "monReseau = nx.Graph()\n",
    "\n",
    "monReseau.add_node(\"Audrey\")\n",
    "monReseau.add_node(\"Nicolas\")\n",
    "monReseau.add_node(\"Alexis\")\n",
    "monReseau.add_node(\"Hélène\")\n",
    "\n",
    "monReseau.add_edge(\"Audrey\", \"Nicolas\")\n",
    "monReseau.add_edge(\"Audrey\", \"Alexis\")\n",
    "monReseau.add_edge(\"Nicolas\", \"Alexis\")\n",
    "monReseau.add_edge(\"Hélène\", \"Audrey\")\n",
    "monReseau.add_edge(\"Hélène\", \"Nicolas\")\n",
    "\n",
    "nx.draw(monReseau, with_labels=True)\n",
    "plt.show()\n",
    "\n",
    "print(\"Nombre de personnes =\", monReseau.number_of_nodes())\n",
    "print(\"Nombre de liens =\", monReseau.number_of_edges())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "uxOAGCxNx98x"
   },
   "source": [
    "**Exercice 3** : Que fait le code de la ligne 8 : `monReseau.add_edge(\"Audrey\",\"Nicolas\")` ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "4oHzS1-9wvF2"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "cPo7VAkdEY4r"
   },
   "source": [
    "**Exercice 4** : Quelles sont les deux personnes qui ne sont pas directement en relation ? Que faudrait-il faire pour les mettre en relation ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Jh1p2r64EpXs"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "MwuOxgaCFm6F"
   },
   "source": [
    "## 3 Un graphe orienté"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "RN0DPh8f2yyD"
   },
   "source": [
    "Lire puis exécuter plusieurs fois le code suivant, qui est presque le même que le code précédent :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "IaPjWjY42Rwg"
   },
   "outputs": [],
   "source": [
    "plt.clf()\n",
    "\n",
    "monReseau = nx.DiGraph() # création d'un graphe orienté\n",
    "\n",
    "monReseau.add_node(\"Audrey\")\n",
    "monReseau.add_node(\"Nicolas\")\n",
    "monReseau.add_node(\"Alexis\")\n",
    "monReseau.add_node(\"Hélène\")\n",
    "\n",
    "monReseau.add_edge(\"Audrey\", \"Nicolas\")  # lien de Audrey vers Nicolas\n",
    "monReseau.add_edge(\"Audrey\", \"Alexis\")\n",
    "monReseau.add_edge(\"Nicolas\", \"Alexis\")\n",
    "monReseau.add_edge(\"Hélène\", \"Audrey\")\n",
    "monReseau.add_edge(\"Hélène\", \"Nicolas\")\n",
    "monReseau.add_edge(\"Alexis\", \"Audrey\")\n",
    "\n",
    "nx.draw(monReseau, with_labels=True)\n",
    "plt.show()\n",
    "\n",
    "print(\"Nombre de personnes =\", monReseau.number_of_nodes())\n",
    "print(\"Nombre de liens =\", monReseau.number_of_edges())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "LBbIhfK03kea"
   },
   "source": [
    "**Exercice 5** : Qu'est-ce qui a changé par rapport au graphe précédent ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Qd1Wyv4K34Jn"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "afK4phwCGCF-"
   },
   "source": [
    "**Exercice 6** : Pourquoi la relation entre Audrey et Alexis est-elle différente des autres ? Pourquoi voit-on 5 segments mais 6 liens ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "9v7atjS3GK5Q"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "kfR8oJj-Bmcz"
   },
   "source": [
    "**Exercice 7** : Ce dernier graphe est dit **orienté**, par opposition au graphe du paragraphe précédent qui est dit **non orienté**. Parmi Facebook, Twitter, Instagram, WhatsApp, Snapchat, citer un réseau social orienté et un réseau social non orienté."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "JN3ciF_ZC0Zv"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "hmYYAcYqyx6R"
   },
   "source": [
    "## 4 Mon petit réseau social"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Hg5RxXk8zS6o"
   },
   "source": [
    "**Exercice 8** : Choisir six prénoms de votre choix et simuler graphiquement un réseau social **non orienté** entre ces personnes, à l'aide du code appris précédemment."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "q98gY_5qr0oN"
   },
   "outputs": [],
   "source": [
    "# votre code ici\n",
    "...\n",
    "pass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "zqPbPBz_5Bt2"
   },
   "source": [
    "## 5 Un réseau social où tout le monde est amis"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "kuyFwz1rGb68"
   },
   "source": [
    "Lire puis exécuter plusieurs fois le programme suivant."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "JLMauw_55H-s"
   },
   "outputs": [],
   "source": [
    "plt.clf()\n",
    "\n",
    "monRezo = nx.Graph()\n",
    "\n",
    "Liste = [\"Ronaldo\", \"Messi\", \"Totti\", \"Salah\", \"Mbappé\", \"Neymar\"]\n",
    "\n",
    "for a in Liste:\n",
    "    monRezo.add_node(a)\n",
    "\n",
    "for b in Liste:\n",
    "    for c in Liste:\n",
    "        monRezo.add_edge(b, c)\n",
    "\n",
    "nx.draw(monRezo, with_labels = True)\n",
    "plt.show()\n",
    "\n",
    "print(\"Nombre de personnes =\", monRezo.number_of_nodes())\n",
    "print(\"Nombre de liens =\", monRezo.number_of_edges())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "P5huorFeIGxU"
   },
   "source": [
    "**Exercice 9** : Expliquer ce que font les lignes 8, 9 et 10 du programme."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "CLNCYe4WIYJ6"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "ujqLQSVfKPxz"
   },
   "source": [
    "## 6 Un réseau social plus ou moins social"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Z5Rag5B61yDX"
   },
   "source": [
    "La fonction `random()` renvoie un nombre réel au hasard entre 0 et 1.\n",
    "\n",
    "Lire puis exécutez plusieurs fois de suite le programme suivant :"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "colab": {},
    "colab_type": "code",
    "id": "gVBk9JA95mEH"
   },
   "outputs": [],
   "source": [
    "from random import random\n",
    "\n",
    "plt.clf()\n",
    "\n",
    "monRezo = nx.Graph()\n",
    "\n",
    "Liste = [\"Ronaldo\", \"Messi\", \"Totti\", \"Salah\", \"Pogba\", \"Neymar\"]\n",
    "p = 0.3\n",
    "\n",
    "for a in Liste:\n",
    "    monRezo.add_node(a)\n",
    "\n",
    "for b in Liste:\n",
    "    for c in Liste:\n",
    "        if random() < p:\n",
    "            monRezo.add_edge(b, c)\n",
    "\n",
    "nx.draw(monRezo, with_labels = True)\n",
    "plt.show()\n",
    "\n",
    "print(\"Nombre de personnes =\", monRezo.number_of_nodes())\n",
    "print(\"Nombre de liens =\", monRezo.number_of_edges())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "HVzfqSdTJLrx"
   },
   "source": [
    "**Exercice 10** : Par défaut `p = 0.3` (ligne 6 du programme). Donnez à `p` la valeur `0.1` puis exécutez plusieurs fois le programme. Donnez à `p` la valeur `0.9` puis exécutez plusieurs fois le programme. Que constatez-vous ? Pourquoi ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Tf0jr-H6o1Xj"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "uUruzBzSo14E"
   },
   "source": [
    "## 7 D'autres réseaux ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "Yan5CMbk5hA8"
   },
   "source": [
    "**Bonus** : Nous venons de simuler un réseau social avec le module Python `networkx`. Quels autres types de réseaux pourrait-on modéliser avec `networkx` ?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "x5sF25-U561q"
   },
   "source": [
    "*---> votre réponse dans cette cellule...*"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "colab_type": "text",
    "id": "_QHg-GV7DCIZ"
   },
   "source": [
    "\n",
    "\n",
    "---\n",
    "\n"
   ]
  }
 ],
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