NnwEstimatorAvg.lua

-- NnwEstimatorAvg.lua
-- estimate value using simple average of k nearest neighbors

-- API overview
if false then
   eavg = NnwEstimatorAvg(xs, ys)
   ok, result = eavg:estimate(query, k)
end -- API overview


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-- CONSTRUCTION
--------------------------------------------------------------------------------

local _, parent = torch.class('NnwEstimatorAvg', 'NnwEstimator')

function NnwEstimatorAvg:__init(xs, ys)
   local v, isVerbose = makeVerbose(false, 'NnwEstimatorAvg:__init')
   parent.__init(self, xs, ys)
end -- NnNnwEstimatorAvg:__init

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-- PUBLIC METHODS
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function NnwEstimatorAvg:estimate(query, k)
   -- estimate y for a new query point using the Euclidean distance
   -- ARGS:
   -- query : 1D Tensor
   -- k     : integer > 0, number of neighbors
   -- RESULTS:
   -- true, estimate : estimate is the estimate for the query
   --                  estimate is a number
   -- false, reason  : no estimate was produced
   --                  reason is a string

   local v, isVerbose = makeVerbose(false, 'NnwEstimatorAvg:estimate')
   verify(v, isVerbose,
          {{query, 'query', 'isTensor1D'},
           {k, 'k', 'isIntegerPositive'}})

   local _, nearestIndices = Nnw.nearest(self._xs, query)
   v('nearestIndices', nearestIndices)
   local nObs = self._ys:size(1)

   local visible = torch.Tensor(nObs):fill(1)  -- all observations are visible

   local ok, result = Nnw.estimateAvg(self._xs,
                                      self._ys,
                                      nearestIndices,
                                      visible,
                                      k)
   return ok, result
end -- estimate()