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Limits on memory for pathfinding algorithms vs lookup tables 
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Joined: Sat May 24, 2014 3:32 pm
Posts: 4
Post Limits on memory for pathfinding algorithms vs lookup tables
I'm writing a C code generator geared toward RobotC and complex tasks for an FTC team, and was wondering about some performance and storage concerns:

  1. How much memory is available for my program's data? It'll be mostly pre-defined lookup tables, generally in the form of multidimensional arrays.
  2. How much NXT memory is available for my program itself? As in, roughly how much code can I expect to fit into a single RobotC compiled program?
  3. How quickly do programs execute, generally? Looking at disassembly most of my generated lines correspond to 2-4 opcodes.

I'm using NXT/Tetrix. My major interest at this point with these questions is for pathfinding. I plan to have a 64x64 grid and be running Djisktra's A* algorithm with a heuristic function that assigns a penalty to turns and is as close to consistent as possible (not sure if consistency/monotonicity is doable with the turn penalty).

Roughly 8 paths would be cached if I decide to use the pre-cached lookup tables.

Instead of a set, I'll probably use a boolean array for the set of nodes visited. The fact that I'm working with a square layout will allow me to use a 2D array for the map needed to reconstruct the path.

I'd love some feedback and answers to my question if anyone has any. Thanks!

Sat May 24, 2014 3:48 pm
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