Class: Ecu::Interpolator

Inherits:
Object
  • Object
show all
Defined in:
lib/ecu/labels/interpolator.rb

Class Method Summary collapse

Class Method Details

.find_position(ref, x) ⇒ Object 



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# File 'lib/ecu/labels/interpolator.rb', line 37

def self.find_position(ref, x)
  x = x.to_f
  n = ref.size - 1
  return [0, 0, 0] if x < ref.first
  return [n, n, 0] if x > ref.last

  ref.each_cons(2).each do |lo, hi|
    if (lo..hi).cover?(x)
      f = (x - lo)/(hi - lo)
      return [ref.index(lo), ref.index(hi), f]
    end
  end
end

.interp(x, y, f) ⇒ Object 



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# File 'lib/ecu/labels/interpolator.rb', line 51

def self.interp(x, y, f)
  x*(1-f) + y*f
end

.interp1(x_ref, y_ref, x) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/ecu/labels/interpolator.rb', line 9

def self.interp1(x_ref, y_ref, x)
  raise ArgumentError unless x_ref.size == y_ref.size
  raise ArgumentError unless x_ref.strictly_mon_inc?

  return y_ref.first if x < x_ref.first
  return y_ref.last  if x > x_ref.last

  x1, x2, fx = find_position(x_ref, x)

  interp(y_ref[x1], y_ref[x2], fx)
end

.interp2(x_ref, y_ref, z_ref, x, y) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/ecu/labels/interpolator.rb', line 21

def self.interp2(x_ref, y_ref, z_ref, x, y)
  raise ArgumentError unless z_ref.size == y_ref.size
  raise ArgumentError unless z_ref.all? { |row| row.size == x_ref.size }
  raise ArgumentError unless x_ref.strictly_mon_inc?
  raise ArgumentError unless y_ref.strictly_mon_inc?

  x1, x2, fx = find_position(x_ref, x)
  y1, y2, fy = find_position(y_ref, y)

  interp(interp(z_ref[y1][x1], z_ref[y2][x1], fy),
         interp(z_ref[y1][x2], z_ref[y2][x2], fy),
         fx)
end