class FinancialCalculator::Ppmt
Calculates the principal portion of a loan or annuity for a particular period
Attributes
@return [Numeric] The ending value of the annuity. Defaults to 0 @api public
@return [Numeric] The number of payments to be made @api public
@return [Boolean] Whether the payment is made at the beginning of the
period (true) or end of the period (false)
@api public
@return [Numeric] The amortization period @api public
@return [Numeric] The current value of the annuity @api public
@return [Numeric] The rate used for calculating the payment amount @api public
@return [DecNum] Result of the PMT calculation @api public
Public Class Methods
Create a new object for calculating the periodic payment of an ordinary annuity @param [Numeric] rate The discount (interest) rate @param [Numeric] period The amortization period @param [Numeric] num_periods
The number of payments to be made @param [Numeric] present_value
The current value of the annuity @param [Numeric] future_value
The ending value of the annuity @param [Boolean] pay_at_beginning. Whether the payment is made at the beginning
of the period (true) or end of the period (false)
@return [FinancialCalculator::Npv] An instance of a PMT calculation
# File lib/financial_calculator/ppmt.rb, line 44 def initialize(rate, period, num_periods, present_value, future_value = 0, pay_at_beginning = false) validate_numerics(rate: rate, period: period, num_periods: num_periods, present_value: present_value, future_value: future_value) @rate = Flt::DecNum(rate.to_s) @period = Flt::DecNum(period) @num_periods = Flt::DecNum(num_periods.to_s) @present_value = Flt::DecNum(present_value.to_s) @future_value = Flt::DecNum(future_value.to_s) @pay_at_beginning = pay_at_beginning @result = solve(@rate, @period, @num_periods, @present_value, @future_value, @pay_at_beginning) end
Public Instance Methods
# File lib/financial_calculator/ppmt.rb, line 62 def inspect "PPMT(#{result})" end
@return [Boolean] Whether the payments are made at the beginning of each period @api public
# File lib/financial_calculator/ppmt.rb, line 58 def pays_at_beginning? @pay_at_beginning end
Private Instance Methods
# File lib/financial_calculator/ppmt.rb, line 68 def solve(rate, period, nper, pv, fv, pay_at_beginning) payment = FinancialCalculator::Pmt.new(rate, nper, pv, fv, pay_at_beginning).result ipmt = FinancialCalculator::Ipmt.new(rate, period, nper, pv, fv, pay_at_beginning).result @result = payment - ipmt end