title: 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: isfinite(coefficient)' crash
body: <p>I get this crash report of which I cannot get the line in my code by symbolicating:</p>
  
  <pre><code>*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason:
  'Invalid parameter not satisfying: isfinite(coefficient)'
  </code></pre>
  
  <p>I searched my code for both function isfinite and variable coefficient and of course I found none. The crash was attributed to System 7.1.2 on iPhone6,1</p>
  
  <p>What might have determined it?</p>