File Coverage

lib/Spreadsheet/Engine/Function/RATE.pm

Criterion	Covered	Total	%
statement	23	23	100.0
branch	4	4	100.0
condition	4	4	100.0
subroutine	9	9	100.0
pod	4	4	100.0
total	44	44	100.0

package Spreadsheet::Engine::Function::RATE;

use strict;
use warnings;

use base 'Spreadsheet::Engine::Fn::investment';

use Spreadsheet::Engine::Fn::Approximator 'iterate';

sub argument_count { -3 => 6 }
sub signature { 'n', 'n', 'n', 'n', 'n', 'n' }
sub result_type { Spreadsheet::Engine::Value->new(type => 'n%') }

sub calculate {
  my ($self, $n, $payment, $pv, $fv, $paytype, $guess) = @_;
  $fv ||= 0;
  $paytype = $paytype ? 1 : 0;

  my $rate = iterate(
    max_iterations => 100,
    initial_guess  => $guess || 0.1,
    function       => sub {
      my $rate = shift;
      return $fv + $pv * (1 + $rate)**$n + $payment * (1 + $rate * $paytype) *
        ((1 + $rate)**$n - 1) / $rate;
    },
  );
  die Spreadsheet::Engine::Error->num unless defined $rate;
  return $rate;
}

1;

__END__