Practica2.ipynb

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   "source": [
    "#Practicas SI\n",
    "\n",
    "#PRÁCTICA 2. Codificación Aritmética (expresión en decimal)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Importamos libreria de matemáticas\n",
    "\n",
    "from collections import Counter\n",
    "from fractions import Fraction\n",
    "from decimal import Decimal\n",
    "\n",
    "import operator\n",
    "import numpy as np"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " \n",
      "Letra:  E\n",
      "Limite Inferior:  4/29\n",
      "Limite Superior:  5/29\n",
      " \n",
      "Letra:  S\n",
      "Limite Inferior:  19/29\n",
      "Limite Superior:  20/29\n",
      " \n",
      "Letra:  T\n",
      "Limite Inferior:  20/29\n",
      "Limite Superior:  21/29\n",
      " \n",
      "Letra:  O\n",
      "Limite Inferior:  15/29\n",
      "Limite Superior:  16/29\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/29\n",
      "Limite Superior:  28/29\n",
      " \n",
      "Letra:  E\n",
      "Limite Inferior:  4/29\n",
      "Limite Superior:  5/29\n",
      " \n",
      "Letra:  S\n",
      "Limite Inferior:  19/29\n",
      "Limite Superior:  20/29\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/29\n",
      "Limite Superior:  28/29\n",
      " \n",
      "Letra:  U\n",
      "Limite Inferior:  21/29\n",
      "Limite Superior:  22/29\n",
      " \n",
      "Letra:  N\n",
      "Limite Inferior:  13/29\n",
      "Limite Superior:  14/29\n",
      " \n",
      "Letra:  A\n",
      "Limite Inferior:  0\n",
      "Limite Superior:  1/29\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/29\n",
      "Limite Superior:  28/29\n",
      " \n",
      "Letra:  P\n",
      "Limite Inferior:  16/29\n",
      "Limite Superior:  17/29\n",
      " \n",
      "Letra:  R\n",
      "Limite Inferior:  18/29\n",
      "Limite Superior:  19/29\n",
      " \n",
      "Letra:  U\n",
      "Limite Inferior:  21/29\n",
      "Limite Superior:  22/29\n",
      " \n",
      "Letra:  E\n",
      "Limite Inferior:  4/29\n",
      "Limite Superior:  5/29\n",
      " \n",
      "Letra:  B\n",
      "Limite Inferior:  1/29\n",
      "Limite Superior:  2/29\n",
      " \n",
      "Letra:  A\n",
      "Limite Inferior:  0\n",
      "Limite Superior:  1/29\n",
      " \n",
      "Letra:  .\n",
      "Limite Inferior:  28/29\n",
      "Limite Superior:  1\n",
      "\n",
      "Mensaje: ESTO ES UNA PRUEBA.\n"
     ]
    }
   ],
   "source": [
    "#Ejercicio 1:  calcula el mensaje\n",
    "\n",
    "alfabeto = \"ABCDEFGHIJKLMNÑOPQRSTUVWXYZ .\"\n",
    "cod = Fraction('0.1613657607216723798346110583')\n",
    "long_msj = 19;\n",
    "\n",
    "tam = len(alfabeto)\n",
    "contador = Counter(alfabeto)\n",
    "\n",
    "def metodoDecodificacion(long_msj,cod,contador):\n",
    "    aux=0\n",
    "    lista = [0]\n",
    "    listaLetras = []\n",
    "    freq_rel_acum = 0\n",
    "    msg=\"\"\n",
    "    \n",
    "    #Rellenamos la lista con los distitnos intervalos\n",
    "    for clave , valor in contador.items():\n",
    "            freq_rel_acum += Fraction(valor,tam)\n",
    "            lista.append(freq_rel_acum)\n",
    "\n",
    "    #print(lista)\n",
    "\n",
    "    while(aux<long_msj):\n",
    "        freq_rel_acum=0\n",
    "        for clave , valor in contador.items():\n",
    "            freq_rel_acum += Fraction(valor,tam)\n",
    "            if(freq_rel_acum >= cod):\n",
    "                caracter = clave\n",
    "                msg += caracter\n",
    "                break\n",
    "\n",
    "        limitInf = lista[lista.index(freq_rel_acum)-1]\n",
    "        print(\" \")\n",
    "        print(\"Letra: \",caracter)\n",
    "        print(\"Limite Inferior: \",limitInf)\n",
    "        print(\"Limite Superior: \",freq_rel_acum)\n",
    "        \n",
    "        cod = Fraction((cod-limitInf),(freq_rel_acum-limitInf))\n",
    "        aux +=1\n",
    "\n",
    "    print(\"\\nMensaje:\",msg)\n",
    "    \n",
    "metodoDecodificacion(long_msj,cod,contador)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
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    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " \n",
      "Letra:  e\n",
      "Limite Inferior:  44/265\n",
      "Limite Superior:  67/265\n",
      " \n",
      "Letra:  l\n",
      "Limite Inferior:  49/53\n",
      "Limite Superior:  256/265\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  67/265\n",
      "Limite Superior:  117/265\n",
      " \n",
      "Letra:  t\n",
      "Limite Inferior:  33/265\n",
      "Limite Superior:  44/265\n",
      " \n",
      "Letra:  i\n",
      "Limite Inferior:  4/265\n",
      "Limite Superior:  18/265\n",
      " \n",
      "Letra:  e\n",
      "Limite Inferior:  44/265\n",
      "Limite Superior:  67/265\n",
      " \n",
      "Letra:  m\n",
      "Limite Inferior:  39/53\n",
      "Limite Superior:  206/265\n",
      " \n",
      "Letra:  p\n",
      "Limite Inferior:  223/265\n",
      "Limite Superior:  232/265\n",
      " \n",
      "Letra:  o\n",
      "Limite Inferior:  171/265\n",
      "Limite Superior:  39/53\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  67/265\n",
      "Limite Superior:  117/265\n",
      " \n",
      "Letra:  e\n",
      "Limite Inferior:  44/265\n",
      "Limite Superior:  67/265\n",
      " \n",
      "Letra:  s\n",
      "Limite Inferior:  18/265\n",
      "Limite Superior:  33/265\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  67/265\n",
      "Limite Superior:  117/265\n",
      " \n",
      "Letra:  v\n",
      "Limite Inferior:  257/265\n",
      "Limite Superior:  258/265\n",
      " \n",
      "Letra:  i\n",
      "Limite Inferior:  4/265\n",
      "Limite Superior:  18/265\n",
      " \n",
      "Letra:  d\n",
      "Limite Inferior:  232/265\n",
      "Limite Superior:  48/53\n",
      " \n",
      "Letra:  a\n",
      "Limite Inferior:  137/265\n",
      "Limite Superior:  161/265\n",
      "\n",
      "Mensaje: el tiempo es vida\n",
      " \n",
      "La entropía de la fuente de texto es:  4.09689\n"
     ]
    }
   ],
   "source": [
    "#Ejercicio 2:  calcula el mensaje\n",
    "\n",
    "texto = \"Existe una cosa muy misteriosa, pero muy cotidiana. Todo el mundo participa de ella,  todo el mundo la conoce, pero muy pocos se paran a pensar en ella.  Casi todos se limitan a tomarla como viene, sin hacer preguntas.  Esta cosa es el tiempo.  (Momo, Michael Ende)\"\n",
    "cod = Fraction('0.247276109705412160222')\n",
    "long_msj = 17;\n",
    "\n",
    "tam = len(texto)\n",
    "contador = Counter(texto)\n",
    "\n",
    "metodoDecodificacion(long_msj,cod,contador)\n",
    "\n",
    "print(\" \")\n",
    "\n",
    "def metodoEntropia(tam):\n",
    "    entropia = 0\n",
    "    for clave , valor in contador.items():\n",
    "        prob = valor/tam\n",
    "        entropia += prob*np.log2(1/prob)\n",
    "    print(\"La entropía de la fuente de texto es: \",\"{0:.5f}\".format(entropia)) \n",
    "\n",
    "metodoEntropia(tam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
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    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " \n",
      "Letra:  (\n",
      "Limite Inferior:  438/455\n",
      "Limite Superior:  439/455\n",
      " \n",
      "Letra:  p\n",
      "Limite Inferior:  22/35\n",
      "Limite Superior:  291/455\n",
      " \n",
      "Letra:  r\n",
      "Limite Inferior:  167/455\n",
      "Limite Superior:  192/455\n",
      " \n",
      "Letra:  i\n",
      "Limite Inferior:  21/65\n",
      "Limite Superior:  167/455\n",
      " \n",
      "Letra:  m\n",
      "Limite Inferior:  237/455\n",
      "Limite Superior:  251/455\n",
      " \n",
      "Letra:  e\n",
      "Limite Inferior:  192/455\n",
      "Limite Superior:  237/455\n",
      " \n",
      "Letra:  r\n",
      "Limite Inferior:  167/455\n",
      "Limite Superior:  192/455\n",
      " \n",
      "Letra:  a\n",
      "Limite Inferior:  101/455\n",
      "Limite Superior:  21/65\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/455\n",
      "Limite Superior:  101/455\n",
      " \n",
      "Letra:  p\n",
      "Limite Inferior:  22/35\n",
      "Limite Superior:  291/455\n",
      " \n",
      "Letra:  a\n",
      "Limite Inferior:  101/455\n",
      "Limite Superior:  21/65\n",
      " \n",
      "Letra:  r\n",
      "Limite Inferior:  167/455\n",
      "Limite Superior:  192/455\n",
      " \n",
      "Letra:  t\n",
      "Limite Inferior:  373/455\n",
      "Limite Superior:  383/455\n",
      " \n",
      "Letra:  e\n",
      "Limite Inferior:  192/455\n",
      "Limite Superior:  237/455\n",
      " \n",
      "Letra:  ,\n",
      "Limite Inferior:  276/455\n",
      "Limite Superior:  22/35\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/455\n",
      "Limite Superior:  101/455\n",
      " \n",
      "Letra:  c\n",
      "Limite Inferior:  349/455\n",
      "Limite Superior:  373/455\n",
      " \n",
      "Letra:  a\n",
      "Limite Inferior:  101/455\n",
      "Limite Superior:  21/65\n",
      " \n",
      "Letra:  p\n",
      "Limite Inferior:  22/35\n",
      "Limite Superior:  291/455\n",
      " \n",
      "Letra:  í\n",
      "Limite Inferior:  431/455\n",
      "Limite Superior:  432/455\n",
      " \n",
      "Letra:  t\n",
      "Limite Inferior:  373/455\n",
      "Limite Superior:  383/455\n",
      " \n",
      "Letra:  u\n",
      "Limite Inferior:  387/455\n",
      "Limite Superior:  398/455\n",
      " \n",
      "Letra:  l\n",
      "Limite Inferior:  398/455\n",
      "Limite Superior:  83/91\n",
      " \n",
      "Letra:  o\n",
      "Limite Inferior:  251/455\n",
      "Limite Superior:  276/455\n",
      " \n",
      "Letra:   \n",
      "Limite Inferior:  27/455\n",
      "Limite Superior:  101/455\n",
      " \n",
      "Letra:  1\n",
      "Limite Inferior:  89/91\n",
      "Limite Superior:  447/455\n",
      " \n",
      "Letra:  )\n",
      "Limite Inferior:  454/455\n",
      "Limite Superior:  1\n",
      "\n",
      "Mensaje: (primera parte, capítulo 1)\n",
      " \n",
      "La entropía de la fuente de texto es:  4.35915\n"
     ]
    }
   ],
   "source": [
    "#Ejercicio 3:  calcula el mensaje\n",
    "\n",
    "texto = \"Un aire marino, pesado y fresco, entró en mis pulmones con la primera  sensación confusa de la ciudad: una masa de casas dormidas; de establecimientos  cerrados; de faroles como centinelas borrachos de soledad. Una respiración  grande, dificultosa, venía con el cuchicheo de la madrugada. Muy cerca, a mi  espalda, enfrente de las callejuelas misteriosas que conducen al Borne, sobre mi  corazón excitado, estaba el mar.  (NADA, Carmen Laforet, 1921-2004)\"\n",
    "cod = Fraction('0.96402816270036736770957975564255630564009')\n",
    "long_msj = 27;\n",
    "tam = len(texto)\n",
    "contador = Counter(texto)\n",
    "\n",
    "metodoDecodificacion(long_msj,cod,contador)\n",
    "print(\" \")\n",
    "metodoEntropia(tam)"
   ]
  },
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   "execution_count": null,
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