cuml/kmeans_demo.ipynb

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   "source": [
    "# K-Means Demo\n",
    "\n",
    "KMeans is a basic but powerful clustering method which is optimized via Expectation Maximization. It randomly selects K data points in X, and computes which samples are close to these points. For every cluster of points, a mean is computed, and this becomes the new centroid.\n",
    "\n",
    "cuML’s KMeans supports the scalable KMeans++ intialization method. This method is more stable than randomnly selecting K points.\n",
    "    \n",
    "The model can take array-like objects, either in host as NumPy arrays or in device (as Numba or cuda_array_interface-compliant), as well as cuDF DataFrames as the input.\n",
    "\n",
    "For information on converting your dataset to cuDF documentation: https://rapidsai.github.io/projects/cudf/en/latest/\n",
    "\n",
    "For additional information on cuML's k-means implementation: https://rapidsai.github.io/projects/cuml/en/latest/api.html#k-means-clustering"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "\n",
    "import pandas as pd\n",
    "import cudf as gd\n",
    "\n",
    "from cuml.datasets import make_blobs\n",
    "\n",
    "from sklearn.metrics import adjusted_rand_score\n",
    "\n",
    "%matplotlib inline\n",
    "import matplotlib.pyplot as plt\n",
    "\n",
    "from sklearn.cluster import KMeans as skKMeans\n",
    "from cuml.cluster import KMeans as cumlKMeans"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Define Parameters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "n_samples = 100000\n",
    "n_features = 2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Generate Data\n",
    "\n",
    "### Device"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "device_data, device_labels = make_blobs(\n",
    "   n_samples=n_samples, n_features=n_features, centers=5, random_state=7)\n",
    "\n",
    "device_data = gd.DataFrame.from_gpu_matrix(device_data)\n",
    "device_labels = gd.Series(device_labels)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Host"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "host_data = device_data.to_pandas()\n",
    "host_labels = device_labels.to_pandas()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Scikit-learn model"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "%%time\n",
    "kmeans_sk = skKMeans(n_clusters=5,\n",
    "                     n_jobs=-1)\n",
    "kmeans_sk.fit(host_data)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## cuML Model"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "%%time\n",
    "kmeans_cuml = cumlKMeans(n_clusters=5)\n",
    "kmeans_cuml.fit(device_data)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Visualize Centroids"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "fig = plt.figure(figsize=(16, 10))\n",
    "plt.scatter(host_data.iloc[:, 0], host_data.iloc[:, 1], c=host_labels, s=50, cmap='viridis')\n",
    "\n",
    "#plot the sklearn kmeans centers with blue filled circles\n",
    "centers_sk = kmeans_sk.cluster_centers_\n",
    "plt.scatter(centers_sk[:,0], centers_sk[:,1], c='blue', s=100, alpha=.5)\n",
    "\n",
    "#plot the cuml kmeans centers with red circle outlines\n",
    "centers_cuml = kmeans_cuml.cluster_centers_\n",
    "plt.scatter(centers_cuml['0'].values, centers_cuml['1'].values, facecolors = 'none', edgecolors='red', s=100)\n",
    "\n",
    "plt.title('cuml and sklearn kmeans clustering')\n",
    "\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Compare Results"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "%%time\n",
    "cuml_score = adjusted_rand_score(host_labels, kmeans_cuml.labels_)\n",
    "sk_score = adjusted_rand_score(host_labels, kmeans_sk.labels_)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "threshold = 1e-4\n",
    "\n",
    "passed = (cuml_score - sk_score) < threshold\n",
    "print('compare kmeans: cuml vs sklearn labels_ are ' + ('equal' if passed else 'NOT equal'))"
   ]
  }
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