Module: PerfectShape::Math

Defined in:
lib/perfect_shape/math.rb

Overview

Perfect Shape Math utility methods

Mostly ported from java.lang.Math: docs.oracle.com/javase/8/docs/api/java/lang/Math.html

Also includes standard Ruby ::Math utility methods

Class Method Summary collapse

Class Method Details

.const_missing(constant) ⇒ Object 



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# File 'lib/perfect_shape/math.rb', line 108

def const_missing(constant)
  ::Math::const_get(constant)
end

.degrees_to_radians(degrees) ⇒ Object

converts angle from degrees to radians (normalizing to BigDecimal)



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# File 'lib/perfect_shape/math.rb', line 36

def degrees_to_radians(degrees)
  (Math::PI/BigDecimal('180'))*BigDecimal(degrees.to_s)
end

.ieee754_remainder(x, y) ⇒ Object Also known as: ieee_remainder

Computes the remainder operation on two arguments as prescribed by the IEEE 754 standard.

Algorithm is exactly: x – (round(x/y)*y)

The ‘round` part rounds to the nearest even number when it is a halfway between n & y (integer + 0.5 number)

The remainder value is mathematically equal to x - y × n, where n is the mathematical integer closest to the exact mathematical value of the quotient x/y, and if two mathematical integers are equally close to x/y, then n is the integer that is even. If the remainder is zero, its sign is the same as the sign of the first argument. Special cases:

If either argument is NaN, or the first argument is infinite, or the second argument is positive zero or negative zero, then the result is NaN.

If the first argument is finite and the second argument is infinite, then the result is the same as the first argument.

Parameters:

  • x —

    the dividend.

  • y —

    the divisor.

Returns:

  • the remainder when x is divided by y.



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# File 'lib/perfect_shape/math.rb', line 78

def ieee754_remainder(x, y)
  x = BigDecimal(x.to_s)
  y = BigDecimal(y.to_s)
  return BigDecimal::NAN if x.nan? || y.nan? || x.infinite? || y.zero?
  return x if x.finite? && y.infinite?
  division = x / y
  rounded_division_low = BigDecimal(division.floor)
  rounded_division_high = BigDecimal(division.ceil)
  rounded_division_half = rounded_division_low + 0.5
  rounded_division = if division == rounded_division_half
    rounded_division_low.to_i.even? ? rounded_division_low : rounded_division_high
  else
    BigDecimal(division.round)
  end
  (x - (rounded_division * y))
end

.method_missing(method_name, *args, &block) ⇒ Object 



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# File 'lib/perfect_shape/math.rb', line 100

def method_missing(method_name, *args, &block)
  if ::Math.respond_to?(method_name, true)
    ::Math.send(method_name, *args, &block)
  else
    super
  end
end

.normalize_degrees(angle) ⇒ Object

Normalizes the specified angle into the range -180 to 180.



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# File 'lib/perfect_shape/math.rb', line 41

def normalize_degrees(angle)
  angle = BigDecimal(angle.to_s)
  if angle > 180.0
    if angle <= (180.0 + 360.0)
      angle = angle - BigDecimal('360.0')
    else
      angle = Math.ieee_remainder(angle, 360.0)
      # IEEEremainder can return -180 here for some input values...
      angle = BigDecimal('180.0') if angle == -180.0
    end
  elsif angle <= -180.0
    if angle > (-180.0 - 360.0)
      angle = angle + BigDecimal('360.0')
    else
      angle = Math.ieee_remainder(angle, 360.0)
      # IEEEremainder can return -180 here for some input values...
      angle = BigDecimal('180.0') if angle == -180.0
    end
  end
  angle
end

.radians_to_degrees(radians) ⇒ Object

converts angle from radians to degrees (normalizing to BigDecimal)



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# File 'lib/perfect_shape/math.rb', line 31

def radians_to_degrees(radians)
  (BigDecimal('180')/Math::PI)*BigDecimal(radians.to_s)
end

.respond_to?(method_name, include_private = false) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/perfect_shape/math.rb', line 96

def respond_to?(method_name, include_private = false)
  super || ::Math.respond_to?(method_name, include_private)
end