[mlpack-svn] [MLPACK] #167: Different solution for HRectBound::MinDistance(..., std::vector<>)

[MLPACK Trac]

#167: Different solution for HRectBound::MinDistance(..., std::vector<>)
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 Reporter:  rcurtin  |        Owner:  nslagle                           
     Type:  defect   |       Status:  new                               
 Priority:  major    |    Milestone:  MLPACK 1.0                        
Component:  MLPACK   |     Keywords:  bound tree policy template methods
 Blocking:           |   Blocked By:                                    
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 So I was looking at r10459 (actually, just trying to merge it into my own
 changes... SVN is so wonderful!) when I noticed it adds four calls to
 HRectBound:

 {{{
 double MinDistance(const HRectBound& other,
                    const std::vector<size_t>& indices);
 double MinDistance(const arma::vec& point,
                    const std::vector<size_t>& indices);
 double MaxDistance(const HRectBound& other,
                    const std::vector<size_t>& indices);
 double MaxDistance(const arma::vec& point,
                    const std::vector<size_t>& indices);
 }}}

 To me this seems to be application-specific (for KCDE, I guess?).  The
 HRectBound class (or any of the Bound classes) implements a pretty strict
 range of methods, in order to reduce the load of someone who would like to
 implement a new type of bound and know that it works with our code okay.

 I'm really hesitant to modify the generic Bound policy class for that
 reason and I think we should pursue an alternate solution for this
 problem.

 Could we design something like an HRectConditionalBound, where the list of
 allowed indices is given at constructor time and can be modified by the
 user?  Then, the regular MinDistance() and MaxDistance() would only work
 on the "good" indices by default.

 I don't know if that solution is applicable to the situation; maybe we can
 get the situation here in more detail and come up with a solution through
 that means?  My only goal is to avoid increasing the footprint of a
 generic template class though, so as to reduce the load on someone making
 a custom bound.  We split out HRectPeriodicBound from HRectBound for that
 reason (they used to be the same class).

-- 
Ticket URL: <http://trac.research.cc.gatech.edu/fastlab/ticket/167>
MLPACK <www.fast-lab.org>
MLPACK is an intuitive, fast, and scalable C++ machine learning library developed by the FASTLAB at Georgia Tech under Dr. Alex Gray.