finance_rb
This package is a ruby native port of the numpy-financial package with some helpful additional functions.
The functions in this package are a scalar version of their vectorised counterparts in the numpy-financial library.
Currently, only some functions are ported,
which are as follows:
| numpy-financial function | ruby native function ported? | info |
|---|---|---|
| fv | ✅ | Computes the future value |
| ipmt | ✅ | Computes interest payment for a loan |
| pmt | ✅ | Computes the fixed periodic payment(principal + interest) made against a loan amount |
| ppmt | ✅ | Computes principal payment for a loan |
| nper | ✅ | Computes the number of periodic payments |
| pv | ✅ | Computes the present value of a payment |
| rate | ✅ | Computes the rate of interest per period |
| irr | ✅ | Computes the internal rate of return |
| npv | ✅ | Computes the net present value of a series of cash flow |
| mirr | ✅ | Computes the modified internal rate of return |
Things to be done:
- Xirr
- More specs for edge cases
- Fee, currency protection and other cool stuff for advanced usage
- Better errors
- A detailed documentation for all methods
Documentation
Detailed documentation is available at rubydoc.
Basic usage
There is no need to create a loan class to calculate some basic functions, such as npv, irr, or mirr. Simply call a needed method with required arguments using calculations class.
-
IRR (Internal Rate of Return)
Finance::Calculations.irr([-4000,1200,1410,1875,1050]) => 0.14299344106053188
-
MIRR (Modified Internal Rate of Return)
Finance::Calculations.mirr([100, 200, -50, 300, -200], 0.05, 0.06) => 0.3428233878421769
-
NPV (Net Present Value)
Finance::Calculations.net_present_value(0.1, [-100, 6, 6, 6]) => -85.07888805409468
Advanced Usage
Create a loan instance, and pass available parameters for nominal annual rate, duration (in months), and amount of loan.
loan = Finance::Loan.new(nominal_rate: 0.1, duration: 12, amount: 1000)
loan.pmt # => -87.9158872300099Available methods: pmt, ipmt, ppmt, nper, pv, fv, rate.
Installation
finance_rb is available as a gem, to install it just install the gem:
gem install finance_rb
If you're using Bundler, add the gem to Gemfile.
gem 'finance_rb'
Run bundle install.
Running tests
bundle exec rspec spec/
Available Functions
** Simple financial functions **
- fv(rate, nper, pmt, pv[, when]) Compute the future value.
- pv(rate, nper, pmt[, fv, when]) Compute the present value.
- npv(rate, values) Returns the NPV (Net Present Value) of a cash flow series.
- pmt(rate, nper, pv[, fv, when]) Compute the payment against loan principal plus interest.
- ppmt(rate, per, nper, pv[, fv, when]) Compute the payment against loan principal.
- ipmt(rate, per, nper, pv[, fv, when]) Compute the interest portion of a payment.
- irr(values) Return the Internal Rate of Return (IRR).
- mirr(values, finance_rate, reinvest_rate) Modified internal rate of return.
- nper(rate, pmt, pv[, fv, when]) Compute the number of periodic payments.
- nrate(nper, pmt, pv, fv[, when, guess, tol, …]) Compute the rate of interest per period.
Contributing
- Fork it ( https://github.com/wowinter13/finance_rb/fork )
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create a new Pull Request
License
MIT License. See LICENSE for details.