title: Strange results being returned from vDSP_conv
body: <p>I've been using the Accelerate framework to do some audio signal processing and I've been using the <code>vDSP_conv</code> function to perform some cross-correlations. Usually, the values returned look like this (left column is the array index, and right column is the value of the array at that index after being returned from <code>vDSP_conv</code>):</p>
  
  <pre><code>125001  1.576556  
  125002  1.523622  
  125003  1.439102  
  125004  1.593097  
  125005  1.171977  
  125006  0.020228  
  125007  -0.988876  
  125008  -1.526720  
  125009  -1.056652  
  125010  -0.181521  
  125011  -0.029592  
  125012  0.077848  
  125013  0.319371  
  125014  0.080034  
  125015  -0.629983
  </code></pre>
  
  <p>But sometimes the results look like this, for no discernible reason:</p>
  
  <pre><code>125001  65531903404620711577128764702720.000000  
  125002  271523249688835947415863891591168.000000  
  125003  253191001846134141440285462233088.000000  
  125004  197376212065818453160643396632576.000000  
  125005  247836891833411757917279954665472.000000  
  125006  203601464352748581549908776976384.000000  
  125007  193256115501319341596977567629312.000000  
  125008  55431884287617507551879029063680.000000  
  125009  -242471930502532513482802284462080.000000  
  125010  -259877560883016098488551924039680.000000  
  125011  -201496656800953613737511541014528.000000  
  125012  -240627419186810410707269384667136.000000  
  125013  -241660441463967832878539113234432.000000  
  125014  -169626548145197368918504628027392.000000  
  125015  -157041504634723839288379166425088.000000  
  </code></pre>
  
  <p>I ran the program again after getting these results, and they went back to the original (correct) results. Has anyone else experienced this or have any ideas as to why it's happening?</p>