Class: Fuzzyrb::FuzzySet

Inherits:
Object
  • Object
show all
Defined in:
lib/fuzzy_set.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(points) ⇒ FuzzySet

Returns a new instance of FuzzySet.



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# File 'lib/fuzzy_set.rb', line 14

def initialize(points)
  @points = points.sort.uniq_values
end

Instance Attribute Details

#points ⇒ Object (readonly)

Returns the value of attribute points.



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# File 'lib/fuzzy_set.rb', line 43

def points
  @points
end

Class Method Details

.trapezoid(array) ⇒ Object

Raises:

  • (Exception) 


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# File 'lib/fuzzy_set.rb', line 3

def self.trapezoid(array)
  raise Exception.new("Trapezoid must have array length 4") if array.length != 4
  raise Exception.new("Trapezoid arguments must be nondecreasing") unless array.non_decreasing
  points = []
  points << Point.new(array[0], 0) unless array[1] == array[0]
  points << Point.new(array[1], SCALE) 
  points << Point.new(array[2], SCALE) unless array[2] == array[1]
  points << Point.new(array[3], 0) unless array[3] == array[2]
  FuzzySet.new(points)
end

Instance Method Details

#&(other) ⇒ Object

Choose min of current and other set



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# File 'lib/fuzzy_set.rb', line 35

def &(other)
  points = [@points, crosspoints(other)].flatten.uniq_values.sort
  res = []
  points.each { |point|
    res << point if self[point.x]-EPSILON < point.y and self[point.x]+EPSILON > point.y and other[point.x]+EPSILON >= self[point.x]
  }
  FuzzySet.new(res)
end

#+(other) ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 18

def +(other)
  points = [@points, other.points, intersections(other)].flatten.uniq_values.sort
  res = points.reject { |point|
    self[point.x]-EPSILON > point.y or other[point.x]-EPSILON > point.y
  }
  FuzzySet.new(res)
end

#[](value) ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 84

def [](value)
  if value<@points[0].x
    return @points[0].y
  elsif value > @points.last.x
    return @points.last.y
  end
  idx = 0
  while (@points[idx].x < value)
    idx += 1
  end
  return @points[idx].y if @points[idx].x == value
  x1 = @points[idx-1].x
  x2 = @points[idx].x
  y1 = @points[idx-1].y
  y2 = @points[idx].y
  return 1.0*(y2 - y1)/(x2-x1) * (value - x1) + y1
end

#centerOfGravity ⇒ Object

Raises:

  • (Exception) 


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# File 'lib/fuzzy_set.rb', line 45

def centerOfGravity()
  nominator = 0.0
  denominator = 0.0
  # puts "Length: #{@points.length}"
  for i in 1..@points.length-1
    line = Line.new(@points[i], @points[i-1])
    # puts "#{nominator}, #{denominator}, #{line.a}, #{line.b}"
    # pp @points[i], @points[i-1]
    x2 = points[i].x
    x1 = points[i-1].x
    nominator += line.a * x2**3/3 + line.b * x2**2/2 - line.a * x1**3/3 - line.b * x1**2/2
    denominator += line.a * x2**2/2 + line.b * x2 - line.a * x1**2/2 - line.b * x1
  end

  return 0 if nominator.abs <= EPSILON
  raise Exception.new("Runtime exception: denominator cannot be null") if denominator == 0
  nominator/denominator
end

#firstMaximum ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 64

def firstMaximum()
  maxIdx = 0
  for i in 0..@points.length-1
    if @points[i].y > @points[maxIdx].y
      maxIdx = i
    end
  end
  @points[maxIdx].x
end

#min(value) ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 26

def min(value)
  line = Line.new(Point.new(0, value), Point.new(1, value))
  points = [@points, intersections(line)].flatten.uniq_values.sort.map { |p| Point.new(p.x, [p.y, value].min)}
  # reject all points that has higher membership than this fuzzy set
  res = points.reject { |p| self[p.x] - EPSILON > value }
  FuzzySet.new(res)
end

#scale(factor) ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 74

def scale(factor)
  fs = FuzzySet.new(@points.map { |p| p.clone() })
  fs.scale!(factor)
end

#scale!(factor) ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 79

def scale!(factor)
  @points.each { |point| point.y *= factor / SCALE }
  self
end

#toLines ⇒ Object 



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# File 'lib/fuzzy_set.rb', line 102

def toLines
  lines = []
  for i in 1..@points.length-1
    lines << Line.new(@points[i], @points[i-1])
  end
  lines
end