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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