[18425] | 1 | #
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| 2 | # BigDecimal utility library.
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| 3 | #
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| 4 | # To use these functions, require 'bigdecimal/util'
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| 5 | #
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| 6 | # The following methods are provided to convert other types to BigDecimals:
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| 7 | #
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| 8 | # String#to_d -> BigDecimal
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| 9 | # Float#to_d -> BigDecimal
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| 10 | # Rational#to_d -> BigDecimal
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| 11 | #
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| 12 | # The following method is provided to convert BigDecimals to other types:
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| 13 | #
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| 14 | # BigDecimal#to_r -> Rational
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| 15 | #
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| 16 | # ----------------------------------------------------------------------
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| 17 | #
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| 18 | class Float < Numeric
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| 19 | def to_d
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| 20 | BigDecimal(self.to_s)
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| 21 | end
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| 22 | end
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| 23 |
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| 24 | class String
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| 25 | def to_d
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| 26 | BigDecimal(self)
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| 27 | end
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| 28 | end
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| 29 |
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| 30 | class BigDecimal < Numeric
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| 31 | # Converts a BigDecimal to a String of the form "nnnnnn.mmm".
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| 32 | # This method is deprecated; use BigDecimal#to_s("F") instead.
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| 33 | def to_digits
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| 34 | if self.nan? || self.infinite? || self.zero?
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| 35 | self.to_s
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| 36 | else
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| 37 | i = self.to_i.to_s
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| 38 | s,f,y,z = self.frac.split
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| 39 | i + "." + ("0"*(-z)) + f
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| 40 | end
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| 41 | end
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| 42 |
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| 43 | # Converts a BigDecimal to a Rational.
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| 44 | def to_r
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| 45 | sign,digits,base,power = self.split
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| 46 | numerator = sign*digits.to_i
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| 47 | denomi_power = power - digits.size # base is always 10
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| 48 | if denomi_power < 0
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| 49 | Rational(numerator,base ** (-denomi_power))
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| 50 | else
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| 51 | Rational(numerator * (base ** denomi_power),1)
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| 52 | end
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| 53 | end
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| 54 | end
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| 55 |
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| 56 | class Rational < Numeric
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| 57 | # Converts a Rational to a BigDecimal
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| 58 | def to_d(nFig=0)
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| 59 | num = self.numerator.to_s
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| 60 | if nFig<=0
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| 61 | nFig = BigDecimal.double_fig*2+1
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| 62 | end
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| 63 | BigDecimal.new(num).div(self.denominator,nFig)
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| 64 | end
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| 65 | end
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