FinancialMaths

more functions will be added soon

New in version 0.0.5

1. New functions for loan amortizations
2. New payments calculations
3. New unit tests

Pending

1. include more functions
2. add some unit tests

Installation

Add this line to your application's Gemfile:

gem 'financial_maths'

And then execute:

$ bundle

Or install it yourself as:

$ gem install financial_maths

Usage

require "financial_maths"

include FinancialMaths

The lists of the methods and their params

Variable amortization payment due

due_variable_payment_amortization (periods, amount, rate, payment)

$ due_variable_payment_amortization(5,10000,1.8,2000)
$ [{:period=>0, :monthly_payment=>nil, :interest=>nil, :payment=>nil, :balance=>10000},
 {:period=>1, :payment=>20000.0, :interest=>18000.0, :monthly_payment=>2000, :balance=>8000},
 {:period=>2, :payment=>16400.0, :interest=>14400.0, :monthly_payment=>2000, :balance=>6000},
 {:period=>3, :payment=>12800.0, :interest=>10800.0, :monthly_payment=>2000, :balance=>4000},
 {:period=>4, :payment=>9200.0, :interest=>7200.0, :monthly_payment=>2000, :balance=>2000},
 {:period=>5, :payment=>5600.0, :interest=>3600.0, :monthly_payment=>2000, :balance=>0}]

Variable payment amortization anticipated

anticipated_variable_payment_amortization (periods, amount, rate, payment)

$ anticipated_variable_payment_amortization(5,10000,1.8,2000)
$ [{:period=>0, :payment=>20000.0, :interest=>18000.0, :monthly_payment=>2000, :balance=>8000},
  {:period=>1, :payment=>16400.0, :interest=>14400.0, :monthly_payment=>2000, :balance=>6000},
  {:period=>2, :payment=>12800.0, :interest=>10800.0, :monthly_payment=>2000, :balance=>4000},
  {:period=>3, :payment=>9200.0, :interest=>7200.0, :monthly_payment=>2000, :balance=>2000},
  {:period=>4, :payment=>5600.0, :interest=>3600.0, :monthly_payment=>2000, :balance=>0}]

Amortization with fixed payment due

due_fixed_payment_amortization (periods, amount, rate, payment)

$ due_fixed_payment_amortization(5,10000,1.8,2109)
$ [{:period=>0, :monthly_payment=>nil, :interest=>nil, :payment=>nil, :balance=>10000},
  {:period=>1, :payment=>2109, :interest=>18000.0, :monthly_payment=>-15891.0, :balance=>25891.0},
  {:period=>2, :payment=>2109, :interest=>46603.8, :monthly_payment=>-44494.8, :balance=>70385.8},
  {:period=>3, :payment=>2109, :interest=>126694.44, :monthly_payment=>-124585.44, :balance=>194971.24},
  {:period=>4, :payment=>2109, :interest=>350948.232, :monthly_payment=>-348839.232, :balance=>543810.4720000001},
  {:period=>5, :payment=>2109, :interest=>978858.8496000002, :monthly_payment=>-976749.8496000002, :balance=>1520560.3216000004}]

Variable payment amortization anticipated

anticipated_fixed_payment_amortization (periods, amount, rate, payment)

Find future given the present value

future_given_present (present_value, interest, term)

$ future_given_present(10000,1.8,5)
$ 1721036.8

Find present given the future

present_given_future (future_value, interest, term)

$ present_given_future(10000,1.8,5)
$ 58.1045

Find annuity present value given

annuity_given_present (present_value, interest, term)

$ annuity_given_present(10000,1.8,5)
$ 18105.1994

Find the future value annuity given

annuity_given_future (future_value, interest, term)

Find present given the annuity

present_given_annuity (annuity, interest, term)

Find future given the annuity

future_given_annuity (annuity, interest, term)

Find effective rate given the nominal rate due

efective_given_nominal_due (nominal_rate, term)

Find effective rate given the nominal rate anticipated

efective_given_nominal_antipipated (nominal_rate, term)

Find effective nominal rate given anticipated

nominal_antipiated_given_efective (nominal_rate, term)

Find effective nominal rate given anticipated

nominal_due_given_efective (nominal_rate, term)

Find the fixed anticipated

anticipated_fixed_payment (present_value, rate, term)

Finding variable amount

variable_payment (amount, periods)

$ variable_payment(10000,5)
$ 2000.0

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request