Negative exponential decay function

Returns a negative exponential weighting function to be used inside accessibility calculating functions.

This function is generic over any kind of numeric travel cost, such as distance, time and money.

Usage

decay_exponential(decay_value)

Arguments

decay_value

A numeric vector. The calibration parameters that, when multiplied by the travel cost, are used as the exponent of e in the negative exponential function.

Value

A function that takes a generic travel cost vector (numeric) as an input and returns a list of weight vectors (a list of numeric vectors, named after the arguments passed to the decay function).

See also

Other decay functions: decay_binary(), decay_linear(), decay_logistic(), decay_power(), decay_stepped()

Examples

weighting_function <- decay_exponential(decay_value = 0.1)

weighting_function(c(20, 30))
#> $`0.1`
#> [1] 0.13533528 0.04978707
#> 

weighting_function <- decay_exponential(decay_value = c(0.1, 0.2))

weighting_function(c(20, 30))
#> $`0.1`
#> [1] 0.13533528 0.04978707
#> 
#> $`0.2`
#> [1] 0.018315639 0.002478752
#>