title: Good way to hash a float vector?
body: <p>I am well aware of all the problems involved in comparing floats. This is exactly the reason for this question.<br>
  I'm looking to create a fast hash table for values that are 3D vectors (3 floats - x,y,z). It can be assumed that the length of the vector is always 1.0 (<code>sqrt(x*x+y*y+z*z)</code> is 1.0)  </p>
  
  <p>Essentially this means that I'm looking for a hash function that takes values that are almost equal to the same unsigned int value and a corresponding equality operator that is true if the hash values are equal (not not necessarily only if they are equal)</p>
  
  <p><strong>Edit</strong> -<br>
  False positives (i.e. vectors that are different but map to the same bucket) are a given since this is a hash table.<br>
  False negatives (i.e. Vectors that are close but map to different buckets) are undesirable but it seems that there is no way to avoid them. In my case, they will not causes total breakage, just some data duplication which is something I'll have to live with.</p>