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      "start_time": "2018-05-29T16:30:46.563631Z"
   },
   "id": "eaGiz29cH2QM",
   "colab_type": "text"
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   "source": [
   "# HW Overview\n",
   "\n",
   "Please complete all core assignment tasks. For 50% bonus points please complete the optional stretech assignment tasks that will involve more theory and programming.\n",
   "\n",
   "The goals of this HW include the following:\n",
   "* master pipelines for regression prediction problems\n",
   " * Exploratory data analysis\n",
   " * Date preprocessing\n",
   " * Data standardization\n",
   " * Deal with missing data\n",
   " * Dealing with categorical input features via, say, OHE \n",
   " * Linear regression modeling (regularized or not)\n",
   " * Various performance metrics\n",
   " \n",
   " \n",
   "Please consult Canvas for the grading rubric (check Module 05 -> HW 05).\n"
   ]
},
{
   "cell_type": "markdown",
   "metadata": {
   "id": "I7jipqcJH2QQ",
   "colab_type": "text"
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   "source": [
   "# Linear Regression Basics"
   ]
},
{
   "cell_type": "markdown",
   "metadata": {
   "id": "4zKhKLuiH2QR",
   "colab_type": "text"
   },
   "source": [
   "## Batch Gradient Descent"
   ]
},
{
   "cell_type": "markdown",
   "metadata": {
   "id": "IQhPQJRHH2QT",
   "colab_type": "text"
   },
   "source": [
   "Use the starter code below to calculate the first iteration of gradient descent to minimize the objective function \n",
   "$2x^2+ 4x$. We assume that the initial guess is $x=2$ of  and a stepsize of 0.1 "
   ]
},
{
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      "height": 34
   },
   "outputId": "e89fb8ff-0c2c-47ac-fa60-b4459e0672e4"
   },
   "source": [
   "#==================================================#\n",
   "#             Your code starts here          #\n",
   "#==================================================#\n",
   "\n",
   "# TODO - change above to :\n",
   "def step(x, eta):\n",
   " update = eta * 4*x+4 #Insert f prime here\n",
   " return x - update\n",
   "\n",
   "step(x=2, eta=0.1)\n",
   "#==================================================#\n",
   "#             Your code ends here             #\n",
   "#==================================================#"
   ],
   "execution_count": 63,
   "outputs": [
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      "data": {
         "text/plain": [
         "-2.8"
         ]
      },
      "metadata": {
         "tags": []
      },
      "execution_count": 63
   }
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{
   "cell_type": "markdown",
   "metadata": {
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   "source": [
   "## Stochastic Gradient Descent"
   ]
},
{
   "cell_type": "markdown",
   "metadata": {
   "id": "DTlOzJ4pH2Qd",
   "colab_type": "text"
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   "source": [
   "Assume you are learning a linear regression model (using the mean squared error objective loss function) via stochastic gradient descent with the following setting:\n",
   "* X = [2, 3], y = 6, (single training example)\n",
   "* a learning rate, α= 0.1 \n",
   "* the current model weight vector is  W = [1, 0, 1], where W[0] denotes the bias term.\n",
   "* Assume the gradient is defined as follows: d E / d W = (y^ - y) X\n",
   "* Use the code below to determine the value of W after applying one iteration of gradient descent?\n"
   ]
},
{
   "cell_type": "code",
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      "height": 34
   },
   "outputId": "bedaee06-e3b6-44da-c71a-6da0de1c0e3c"
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   "source": [
   "import numpy as np\n",
   "#==================================================#\n",
   "#             Your code starts here          #\n",
   "#==================================================#\n",
   "\n",
   "# TODO - change above to :\n",
   "X= [1,2,3]\n",
   "W = [1, 0, 1]\n",
   "y=[6]\n",
   "alpha= 0.1\n",
   "y_hat = sum(np.multiply(W, X))-y\n",
   "gradient= np.multiply(y_hat, X)\n",
   "newW= W - alpha*gradient\n",
   "print (newW)\n",
   "#==================================================#\n",
   "#             Your code ends here             #\n",
   "#==================================================#"
   ],
   "execution_count": 64,
   "outputs": [
   {

Machine Learning - Collaborative Filtering (Recommenders) This...