nuttycom/aftok - Change A2J7B4SCCJYKQV3G2LDHEFNE2GUICO3N3Y5FKF4EUZW5AG7PTDWAC

Initial impl of depreciation function.

Created by Kris Nuttycombe on March 25, 2014

A2J7B4SCCJYKQV3G2LDHEFNE2GUICO3N3Y5FKF4EUZW5AG7PTDWAC

Dependencies

In channels

main

Change contents

Insertion in src/Ananke/TimeLog.hs at line 20 [4.846]
[3.119]
[4.1028]
```
import Data.Ratio
```

Insertion in src/Ananke/TimeLog.hs at line 107 [4.846]

[5.970]

[5.970]


newtype Months = Months Integer 
monthsLength :: Months -> NominalDiffTime
monthsLength (Months i) = fromInteger $ 60 * 60 * 24 * 30 * i
linearDepreciation :: Months -> Months -> Depreciation
linearDepreciation undepPeriod depPeriod = 
  let maxDepreciable :: NominalDiffTime
      maxDepreciable = monthsLength undepPeriod + monthsLength depPeriod

Replacement in src/Ananke/TimeLog.hs at line 118 [4.846]

B:BD[5.971] → [2.49:149]

linearDepreciation :: Depreciation
linearDepreciation = 
  let depf = undefined
  Depreciation depf

[5.971]

      zeroTime :: NominalDiffTime
      zeroTime = fromInteger 0
      depf :: NominalDiffTime -> Rational
      depf dt = if dt < monthsLength undepPeriod 
        then 1
        else toRational (max zeroTime (maxDepreciable - dt)) / toRational maxDepreciable
  in Depreciation depf