title: Connection between A-star search and integer programming, extending A-star
body: <p>Does anyone have a good reference for the connections between A-star search and more general integer programming formulations for a Euclidean shortest path problem?</p>
  
  <p>In particular I'm interested in how one modifies A-star to cope with additional (perhaps path-dependent) constraints, if it makes sense to use a general-purpose LP/IP solver to tackle constrained shortest path problems like this or if something more specialised is required to achieve the same kind of performance obtained by A-star together with a good heuristic.</p>
  
  <p>Not afraid of maths, but most of the references I'm finding for more complex shortest path problems aren't very explicit about how they relate to heuristic-guided algorithms like A* (perhaps because 'A*' is hard to google for...)</p>