Class: XRVG::RandomFilter

Inherits:
Filter show all
Includes:
Attributable
Defined in:
lib/samplation.rb

Overview

RandomFilter class, to resample randomly

Attributes

attribute :mindiff, 0.0
attribute :sort, false

:mindiff specifies which minimum interval must be preserved between random values. Of course, the number of sampling must then be above a given value so that this constraint can be verified.

Instance Method Summary collapse

Methods included from Attributable

included, #initialize

Methods inherited from Filter

#initialize, #transform, with

Methods included from Samplable

#apply_sample, #apply_samples, build, #mean, #rand, #sample, #samples

Methods included from FloatFunctor

#addfilter, #alternate, #apply, #applyhash, #compute, #filter, #generate, #geo, #geofull, #modify, #process, #random, #shuffle, #sin, #ssort, #transform, #trigger

Instance Method Details

#basictransform(v) ⇒ Object

do (0.0..1.0).rand to speed up computation if @mindiff is 0.0



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# File 'lib/samplation.rb', line 445

def basictransform( v )
  return (0.0..1.0).rand
end

#rawtransforms(nsamples) ⇒ Object

make sampling by trying to check :mindiff constraint

generate an exception if not possible



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# File 'lib/samplation.rb', line 407

def rawtransforms(nsamples)
  size  = 1.0
  nsplit = nsamples - 1
  rsize = size - nsplit * @mindiff
  if rsize < 0.0
    raise("RandomFilter rawtransforms error: nsamples #{nsamples} mindiff #{@mindiff} are incompatible")
  end
  
  mindiffs = Array.new( nsplit, @mindiff )
  
  # compute now nsplit values whose sum is <= to rsize
  randarray = [0.0]
  subarray = (0.0..rsize).rand( nsplit-1 )
  if not subarray.is_a? Array
    subarray = [subarray]
  end
  randarray += subarray
  randarray.push( rsize )
  randarray.sort!

  rsizes = Array.new
  randarray.each_cons(2) { |min, max| rsizes.push( (0.0..max-min).rand ) }

  rsum = rsizes.sum
  root = (0.0..(rsize-rsum)).rand

  # Trace("mindiffs #{mindiffs.inspect} rsizes #{rsizes.inspect} rsize #{rsize} rsum #{rsum} root #{root}")

  preresult = []
  mindiffs.zip( rsizes ) {|mindiff, rsize| preresult.push( mindiff + rsize )}

  result = [root]
  preresult.each {|v| newv = result[-1] + v; result << newv }

  return result
end

#transforms(inputs, type) ⇒ Object

:nodoc:



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# File 'lib/samplation.rb', line 449

def transforms( inputs, type )  #:nodoc:
  if type == :split
    @sort = true
  end
  if @mindiff == 0.0
    result = inputs.map { |v| self.basictransform( v ) }
    if @sort
	result = result.sort
    end
    if type == :split
	result[0]  = 0.0
	result[-1] = 1.0
    end
  else
    result = self.rawtransforms( inputs.size )
    if not @sort
	result = result.shuffle
    end
  end
  if self.withboundaries
    result[0] = inputs[0]
    result[-1] = inputs[-1]
  end
  return result
end