Discount a Quantity Over Time. Should be a scalar if time is specified, a vector otherwise

Usage

discount(x, r, first = FALSE, period = 1, linear = FALSE, time)

Arguments

x: numeric. A quantity to discount.
r: discount rate.
first: logical. Should discounting start at the first value?
period: Number of cycle per unit of discount rate.
linear: logical. Should the discount rate vary linearly along the whole period?
time: The cycle number.

Value

A numeric vector of the same length as x.

Details

If the unit of discount rate is the year and a cycle duration is 1 month, period should be 12.

Examples


discount(rep(10, 5), .02)
#> [1] 10.000000  9.803922  9.611688  9.423223  9.238454
discount(rep(10, 5), .02, first = FALSE)
#> [1] 10.000000  9.803922  9.611688  9.423223  9.238454
 
discount(1000, .05, time = 10)
#> [1] 644.6089
discount(1000, .05, period = 2, time = 1:10)
#>  [1] 1000.0000 1000.0000  952.3810  952.3810  907.0295  907.0295  863.8376
#>  [8]  863.8376  822.7025  822.7025
discount(1000, .05, period = 2, time = 1:10, linear = TRUE)
#>  [1] 1000.0000  975.9001  952.3810  929.4286  907.0295  885.1701  863.8376
#>  [8]  843.0192  822.7025  802.8754