title: Square/cubic root lookup table
body: <p>I'm wondering which is the best way to create two lookups table for square root and cubic root of float values in range <code>[0.0, 1.0)</code>.</p>
  
  <p>I already profiled the code and saw that this is quite a strong bottleneck of performances (because I need to compute them for several tenths of thousands of values each). Then I remembered about lookup tables and thought they would help me increasing the performance.</p>
  
  <p>Since my values are in a small range I was thinking about splitting the range with steps of, let's say, <code>0.0025</code> (hoping it's enough) but I'm unsure about which should be the most efficient way to retrieve them.</p>
  
  <p>I can easily populate the lookup table but I need a way to efficiently get the correct value for a given float (which is not discretized on any step). Any suggestions or well known approaches to this problem?</p>
  
  <p>I'm working with a mobile platform, just to specify.</p>
  
  <p>Thanks in advance</p>