[MOAB-dev] ElemUtil madness

[Tim Tautges]

Hi all,
   In various parts of MOAB, I see:

tools/mbcoupler/ElemUtil.hpp:
   namespace Element { class Map {...}; class LinearHex : public Map{...}; ...}
tools/mbcoupler/ElemUtil.cpp:
   namespace ElemUtil { class VolMap{...}; class LinearHexMap : public VolMap{...}; ...}
src/moab/point_locator/element_maps:
   namespace element_utility{ class Linear_hex_map{...} ...}

All with lots of duplicated functionality.  It appears to me that Coupler uses the 1st one above.  I'd like to clean all 
that out right after the release and consolidate down to one version of these things.  After thinking about templates 
vs. inheritance for elements, I've come to the conclusion that we need to use the inheritance model, since we'll never 
know at compile time what kind of elements we're dealing with, so there will always be function invokations via 
indirection, either through virtual function tables or pointer to implementation pattern.  Furthermore, I think 
inheritance gives us the ability to use and override default implementation, e.g. for specializing the tet jacobian and 
its inverse.

Comments?

If you're wondering, I need to sort all this out before tackling the tree searching stuff I'm about to start, since 
evaluating these various elements is the last step in tree searching.

- tim

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              Tim Tautges            Argonne National Laboratory
          (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
  phone (gvoice): (608) 354-1459      1500 Engineering Dr.
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