title: nteract disconnects when using sklearn KernelPCA
body: <p>Everything is working in my nteract notebook until I call scikit-learn's KernelPCA. At that point, the notebook disconnects. So I restart the kernel and run everything again and, again, it disconnects when it hits KernelPCA. It happens every single time. Does anyone know why this is happening and how to fix it?</p>
  <p>These are my imports:</p>
  <pre><code>import numpy as np
  import pandas as pd
  import seaborn as sns
  from sklearn.svm import SVC
  import matplotlib.pyplot as plt
  from sklearn.pipeline import make_pipeline
  from sklearn.decomposition import KernelPCA
  from sklearn.metrics import confusion_matrix
  from sklearn.preprocessing import MinMaxScaler
  from sklearn.model_selection import GridSearchCV
  from sklearn.model_selection import train_test_split
  </code></pre>
  <p>and this is the code where nteract disconnects:</p>
  <pre><code>kpca = KernelPCA(n_components = 2, kernel = 'rbf', gamma = 1 / (2 * (4.8 ** 2))).fit(X)
  kpcs = kpca.transform(X)
  kpcs[0:5, :]
  </code></pre>