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#
# BigDecimal utility library.
# ----------------------------------------------------------------------
# Contents:
#
# String#
# to_d ... to BigDecimal
#
# Float#
# to_d ... to BigDecimal
#
# BigDecimal#
# to_r ... to Rational
#
# Rational#
# to_d ... to BigDecimal
#
# ----------------------------------------------------------------------
#
class Float < Numeric
def to_d
BigDecimal(self.to_s)
end
end
class String
def to_d
BigDecimal(self)
end
end
class BigDecimal < Numeric
# to "nnnnnn.mmm" form digit string
# Use BigDecimal#to_s("F") instead.
def to_digits
if self.nan? || self.infinite? || self.zero?
self.to_s
else
i = self.to_i.to_s
s,f,y,z = self.frac.split
i + "." + ("0"*(-z)) + f
end
end
# Convert BigDecimal to Rational
def to_r
sign,digits,base,power = self.split
numerator = sign*digits.to_i
denomi_power = power - digits.size # base is always 10
if denomi_power < 0
denominator = base ** (-denomi_power)
else
denominator = base ** denomi_power
end
Rational(numerator,denominator)
end
end
class Rational < Numeric
# Convert Rational to BigDecimal
def to_d(nFig=0)
num = self.numerator.to_s
if nFig<=0
nFig = BigDecimal.double_fig*2+1
end
BigDecimal.new(num).div(self.denominator,nFig)
end
end
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