Class: Valuation::CashFlows

Inherits:
Object
  • Object
show all
Defined in:
lib/valuation/cash_flows.rb

Instance Method Summary collapse

Constructor Details

#initialize(flows, options = {}) ⇒ CashFlows

Returns a new instance of CashFlows.



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# File 'lib/valuation/cash_flows.rb', line 5

def initialize(flows, options = {})
  @flows = flows
  @i = options[:i] || 0
end

Instance Method Details

#future_value ⇒ Object 



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# File 'lib/valuation/cash_flows.rb', line 18

def future_value
  value = 0
  @flows.reverse.each_index do |n|
    value += @flows[n] * ((1+@i)**n).to_f
  end
  value
end

#irr(significant_digits = 4) ⇒ Object 



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# File 'lib/valuation/cash_flows.rb', line 26

def irr(significant_digits=4)
  limit = 10**-(significant_digits)
  estimate = @flows.sum/(@flows.size-1.0)/75.0
  delta = estimate.abs
  n = npv(@flows,estimate)
  while n.abs > limit
    sign = n/n.abs
    if (delta.abs < limit/1000)
      delta=estimate.abs               #if we aren't getting anywhere, take a big jump
      return sign/0.0 if (n-@flows[0]).abs < limit
    end
    estimate += (delta/=2) * sign
    n = npv(@flows,estimate)
  end
  estimate
end

#present_value ⇒ Object 



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# File 'lib/valuation/cash_flows.rb', line 10

def present_value
  value = 0
  @flows.each_index do |n|
    value += @flows[n] / ((1+@i)**n).to_f
  end
  value
end