title: Numpy Linalg norm behaving oddly (wrongly)
body: <p>I have a large vector F with a few million entries that gives this inconsistent behaviour when taking norms.</p>
  
  <pre><code>np.linalg.norm(F,2.000001)=3225.96..
  np.linalg.norm(F,2)=inf
  np.linalg.norm(F,1.999999)=3226.01..
  np.linalg.norm(F,1)=inf
  ---------
  np.linalg.norm(F)=inf
  np.linalg.norm(F/12)=inf
  np.linalg.norm(F/13)=246.25
  ---------
  np.sum(F*F)=inf
  np.sum(F*F/169)=60639
  np.sum(F*F/144)=inf
  ---------
  np.all(np.isfinite(F))=True
  np.max(np.abs(F))=11
  ---------
  F.dtype=dtype('float16')
  </code></pre>
  
  <p>Aside from some sort of hacky solution, does anyone have any idea what's going on?</p>