title: ValueError: Floating point image RGB values must be in the 0..1 range. while using matplotlib
body: <p>I want to visualize weights of the layer of a neural network. I'm using pytorch.</p>
  
  <pre><code>import torch
  import torchvision.models as models
  from matplotlib import pyplot as plt
  
  def plot_kernels(tensor, num_cols=6):
      if not tensor.ndim==4:
          raise Exception("assumes a 4D tensor")
      if not tensor.shape[-1]==3:
          raise Exception("last dim needs to be 3 to plot")
      num_kernels = tensor.shape[0]
      num_rows = 1+ num_kernels // num_cols
      fig = plt.figure(figsize=(num_cols,num_rows))
      for i in range(tensor.shape[0]):
          ax1 = fig.add_subplot(num_rows,num_cols,i+1)
          ax1.imshow(tensor[i])
          ax1.axis('off')
          ax1.set_xticklabels([])
          ax1.set_yticklabels([])
  
      plt.subplots_adjust(wspace=0.1, hspace=0.1)
      plt.show()
  vgg = models.vgg16(pretrained=True)
  mm = vgg.double()
  filters = mm.modules
  body_model = [i for i in mm.children()][0]
  layer1 = body_model[0]
  tensor = layer1.weight.data.numpy()
  plot_kernels(tensor)
  </code></pre>
  
  <p>The above gives this error <code>ValueError: Floating point image RGB values must be in the 0..1 range.</code> </p>
  
  <p>My question is should I normalize and take absolute value of the weights to overcome this error or is there anyother way ? 
  If I normalize and use absolute value I think the meaning of the graphs change. </p>
  
  <pre><code>[[[[ 0.02240197 -1.22057354 -0.55051649]
     [-0.50310904  0.00891289  0.15427093]
     [ 0.42360783 -0.23392732 -0.56789106]]
  
    [[ 1.12248898  0.99013627  1.6526649 ]
     [ 1.09936976  2.39608836  1.83921957]
     [ 1.64557672  1.4093554   0.76332706]]
  
    [[ 0.26969245 -1.2997849  -0.64577204]
     [-1.88377869 -2.0100112  -1.43068039]
     [-0.44531786 -1.67845118 -1.33723605]]]
  
  
   [[[ 0.71286005  1.45265901  0.64986968]
     [ 0.75984162  1.8061738   1.06934202]
     [-0.08650422  0.83452386 -0.04468433]]
  
    [[-1.36591709 -2.01630116 -1.54488969]
     [-1.46221244 -2.5365622  -1.91758668]
     [-0.88827479 -1.59151018 -1.47308767]]
  
    [[ 0.93600738  0.98174071  1.12213969]
     [ 1.03908169  0.83749604  1.09565806]
     [ 0.71188802  0.85773659  0.86840987]]]
  
  
   [[[-0.48592842  0.2971966   1.3365227 ]
     [ 0.47920835 -0.18186836  0.59673625]
     [-0.81358945  1.23862112  0.13635623]]
  
    [[-0.75361633 -1.074965    0.70477796]
     [ 1.24439156 -1.53563368 -1.03012812]
     [ 0.97597247  0.83084011 -1.81764793]]
  
    [[-0.80762428 -0.62829626  1.37428832]
     [ 1.01448071 -0.81775147 -0.41943246]
     [ 1.02848887  1.39178836 -1.36779451]]]
  
  
   ..., 
   [[[ 1.28134537 -0.00482408  0.71610934]
     [ 0.95264435 -0.09291686 -0.28001019]
     [ 1.34494913  0.64477581  0.96984017]]
  
    [[-0.34442815 -1.40002513  1.66856039]
     [-2.21281362 -3.24513769 -1.17751861]
     [-0.93520379 -1.99811196  0.72937071]]
  
    [[ 0.63388056 -0.17022935  2.06905985]
     [-0.7285465  -1.24722099  0.30488953]
     [ 0.24900314 -0.19559766  1.45432627]]]
  
  
   [[[-0.80684513  2.1764245  -0.73765725]
     [-1.35886598  1.71875226 -1.73327696]
     [-0.75233924  2.14700699 -0.71064663]]
  
    [[-0.79627383  2.21598244 -0.57396138]
     [-1.81044972  1.88310981 -1.63758397]
     [-0.6589964   2.013237   -0.48532376]]
  
    [[-0.3710472   1.4949851  -0.30245575]
     [-1.25448656  1.20453358 -1.29454732]
     [-0.56755757  1.30994892 -0.39370224]]]
  
  
   [[[-0.67361742 -3.69201088 -1.23768616]
     [ 3.12674141  1.70414758 -1.76272404]
     [-0.22565465  1.66484773  1.38172317]]
  
    [[ 0.28095332 -2.03035069  0.69989491]
     [ 1.97936332  1.76992691 -1.09842575]
     [-2.22433758  0.52577412  0.18292744]]
  
    [[ 0.48471382 -1.1984663   1.57565165]
     [ 1.09911084  1.31910467 -0.51982772]
     [-2.76202297 -0.47073677  0.03936549]]]]
  </code></pre>