bitwise_operation_for_SparseLDA.ipynb

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   "source": [
    "n_book_1 = 3\n",
    "n_book_16 = 10\n",
    "m = 6\n",
    "book = []"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "book.append(int(bin((n_book_1<<m)+1), 2)) # bookにトピック1が3回割り当てられたときの値"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
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   "source": [
    "book.append(int(bin((n_book_16<<m)+16), 2)) # bookにトピック16が10割り当てられたときの値"
   ]
  },
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   "cell_type": "code",
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       "[193, 656]"
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     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "book # n_{w|t}を計算する時はこれを降順にソート"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
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   "outputs": [
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       "3"
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     "execution_count": 5,
     "metadata": {},
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   ],
   "source": [
    "# 復元\n",
    "book[0]>>m #n_book_1と一致"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
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       "1"
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     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "book[0] & pow(2,m)-1 # マスクとの論理積でトピック番号を取り出す"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "10"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "book[1]>>m #n_book_2と一致"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "16"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "book[1] & pow(2,m)-1 # マスクとの論理積でトピック番号を取り出す"
   ]
  }
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