decay_stepped {accessibility} | R Documentation |
Stepped decay function
Description
Returns a stepped 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_stepped(steps, weights)
Arguments
steps |
A |
weights |
A |
Details
When both steps
and weights
parameters are given list
s, their
content are matched element-wise to define each stepped weighting function
i.e. the first element of
steps
is matched to the first element ofweights
, the second element ofsteps
is matched to the second ofweights
, etc. When using a function created withdecay_stepped()
, the output is named after the combination of steps ("s"
) and weights ("w"
)e.g. given the steps
c(10, 20, 30)
and the weightsc(0.66, 0.33, 0)
, the output will be named"s(10,20,30);w(0.66,0.33,0)"
.
Value
A function
that takes a generic travel cost vector (numeric
) as
an input and returns a vector of weights (numeric
).
See Also
Other decay functions:
decay_binary()
,
decay_exponential()
,
decay_linear()
,
decay_logistic()
,
decay_power()
Examples
weighting_function <- decay_stepped(
c(10, 20, 30, 40),
weights = c(0.75, 0.5, 0.25, 0)
)
weighting_function(c(5, 25, 35, 45))
weighting_function <- decay_stepped(
list(c(10, 20, 30, 40), c(10, 20, 30, 40)),
weights = list(c(0.75, 0.5, 0.25, 0), c(0.8, 0.6, 0.4, 0.2))
)
weighting_function(c(5, 25, 35, 45))
# intervals are open on the right, so the values change exactly at each step
weighting_function(c(0, 10, 20, 30, 40))