RosettaCodeData/Task/Approximate-equality/Ruby/approximate-equality.rb

28 lines
1.1 KiB
Ruby

require "bigdecimal"
testvalues = [[100000000000000.01, 100000000000000.011],
[100.01, 100.011],
[10000000000000.001 / 10000.0, 1000000000.0000001000],
[0.001, 0.0010000001],
[0.000000000000000000000101, 0.0],
[(2**0.5) * (2**0.5), 2.0],
[-(2**0.5) * (2**0.5), -2.0],
[BigDecimal("3.14159265358979323846"), 3.14159265358979324],
[Float::NAN, Float::NAN,],
[Float::INFINITY, Float::INFINITY],
]
class Numeric
def close_to?(num, tol = Float::EPSILON)
return true if self == num
return false if (self.to_f.nan? or num.to_f.nan?) # NaN is not even close to itself
return false if [self, num].count( Float::INFINITY) == 1 # Infinity is only close to itself
return false if [self, num].count(-Float::INFINITY) == 1
(self-num).abs <= tol * ([self.abs, num.abs].max)
end
end
testvalues.each do |a,b|
puts "#{a} #{a.close_to?(b) ? '≈' : '≉'} #{b}"
end