title: Real-time updating framework
body: <p>I am trying to implement a real-time updating framework, where changing input data automatically leads to recalculating all dependent results. So I need a kind of subscription mechanism, but a clever one, as I have to handle enormous amounts of data. I like to think about the mechanism as a "calculation tree" or directed graph, with the nodes representing the results, and the edges representing the functions.</p>
  
  <p>Something similar must have been implemented in MS Excel, with the cells being the nodes, but Excel will not fulfill my needs as it is not able to handle large amounts of data, and is not flexible enough.</p>
  
  <p>While in principle I want to be able to browse through the complete calculation tree (including all results in the complete depth of the tree), I know that this could mean storing several Terabytes of data. So I need to be able to forget or skip nodes if the computer runs out of memory, and then recalculate them as needed. And not to forget: while programming the (short!) functions, I don't want to be bothered with endless technical subscribe stuff (ideally this should be taken care of automatically in the framework).</p>
  
  <p>Do you think it's doable, and if so, how would you attack it? Do you know of any component / library which one could use for this type of things? I have thought about publish/subscribe mechanisms and message brokers, but fear they are going to slow down my calculations.</p>
  
  <p>Thx in advance for your responses!</p>
  
  <p>Calle</p>