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.
decay_exponential(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.
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).
Other decay functions:
decay_binary(),
decay_linear(),
decay_logistic(),
decay_power(),
decay_stepped()
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
#>