updated_rio_calc.rb

module PensionsCalculator
  class RioCalc

    def initialize(potsize)
      @potsize = potsize
    end

    def run_calc()
      person = PensionsCalculator::Person.new;
      person.salary = 50000;
      
      contributions = [100, 200, 300, 400, 500, 600, 700, 800, 900, 1000]
      terms = [1,3,5,10,15,20,30]

      contributions.each { |cont|

        print "#{@potsize}, #{cont},"

        terms.each { |term|
          pot = PensionsCalculator::Pot.new(current_pots: PensionsCalculator::CurrentPots.new(pot_1: @potsize), employee_contribution: PensionsCalculator::Contribution.new(salary: person.salary, value: cont*12), employer_contribution: PensionsCalculator::Contribution.new(salary: person.salary, value: 0));
          potvalue = pot.value_at(Date.new((2015+term), 02, 12))
          print  " #{potvalue}," 
        }
        
        print "\n"
        
      }

    end

    def get_slicing_numbers()
      person = PensionsCalculator::Person.new;
      person.salary = 50000;
      contribution = 0
      
      lump_sum_percentages = [0, 0.05, 0.1, 0.2, 0.25, 0.5]
      
      lump_sum_percentages.each { |percent|
        withdrawal = @potsize * percent
        tax_free_withdrawal = withdrawal * 0.25
        taxed_withdrawal = withdrawal * 0.75
        
        remainder = @potsize - withdrawal
        pot_in_ten = PensionsCalculator::Pot.new(current_pots: PensionsCalculator::CurrentPots.new(pot_1: remainder), employee_contribution: PensionsCalculator::Contribution.new(salary: person.salary, value: 0), employer_contribution: PensionsCalculator::Contribution.new(salary: person.salary, value: 0));
        pot_in_ten_value = pot_in_ten.value_at(Date.new((2025), 02, 12)) # assuming looking for value in 10 years time
        
        print "#{@potsize}, "
        print "#{percent*100}%, "
        print "#{withdrawal},  #{withdrawal*0.25}, #{withdrawal*0.75}, "
        print "#{pot_in_ten_value.round(2)}, "
        print "#{(pot_in_ten_value*0.25).round(2)}, "
        print "<<needs working out>>\n"
        
      }
      
    end

  end
end

To run the script
cd spec/dummy/
bundle exec rails c
Then once the ruby shell is running enter
test = PensionsCalculator::RioCalc.new(100000); test.get_slicing_numbers();