np_demo1.ipynb

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   "cell_type": "code",
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   "source": [
    "import numpy as np"
   ]
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    "n = 10"
   ]
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   "source": [
    "$$\n",
    "    D_{n,r}= \\frac{1}{n} \\sum_{j=1}^r \\frac{1}{n-j+1},  {\\rm for} \\; r=1,2,...n\n",
    "$$\n",
    "\n"
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     "text": [
      "[ 0.01        0.02111111  0.03361111  0.04789683  0.06456349  0.08456349\n",
      "  0.10956349  0.14289683  0.19289683  0.29289683]\n"
     ]
    }
   ],
   "source": [
    "x = np.arange(1, n + 1, 1)\n",
    "d = 1 / n * (1 / (n - x + 1)).cumsum()\n",
    "print(d)"
   ]
  },
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