title: 3D sparse matrix implementation?
body: <p>I've found a quite good sparse matrix implementation for c# over <a href="http://www.blackbeltcoder.com/Articles/algorithms/creating-a-sparse-matrix-in-net" rel="nofollow">http://www.blackbeltcoder.com/Articles/algorithms/creating-a-sparse-matrix-in-net</a>.</p>
  
  <p>But as i work in 3d coordinate-system, i need a sparse-matrix implementation that i can use to map the 3d-coordinate system.</p>
  
  <p>Details: I'm storing large amounts of primitive shapes data in memory like cubes. I do have large amounts of them (around 30 million) and i've lots of null (zero) entries around. Given that my each entry costs 1-bytes of entry, i'd like to implement a sparse-matrix so that i can fairly save memory space.</p>
  
  <p>Note: Fast access to matrix cells is a fairly important factor for me, so i'd be trading speed over memory consumption.</p>