utilities: Travel Modeling Utility Functions

In travelr: Functions for Travel Demand Modeling

Description

Functions for Travel Model Development including Root Mean Square Error and a “gamma” function for trip distribution models.

Usage

rmse(v1, v2)
hwy.gamma.function(x,b,c)

Arguments

v1,v2	Vectors to be compared
x	Impedance values to which gamma function will be applied
b,c	Gamma function parameters

Details

rmse computes Root Mean Square Error between two vectors using the formula commonly applied in travel demand modeling. hwy.gamma.function computes friction factors from a vector or matrix of impedance values using the gamma function formula from NCHRP 365 and a scaling factor of 1.

Value

rmse returns a numeric scalar value. hwy.gamma.function returns a numeric object the same shape as x

Author(s)

Jeremy Raw

References

Martin, W.A., and McGuckin, N.A., 1998, NCHRP Report 365: Travel Estimation Techniques for Urban Planning, National Cooperative Highway Research Program / Transportation Research Board

See Also

example(skim.paths) for use of the gamma function.

Examples

v1<-rnorm(100,mean=100,sd=2)
v2<-rnorm(100,mean=100,sd=2)
rmse(v1,v2)

# see example(skim.paths) for use of gamma function

travelr documentation built on May 2, 2019, 5:17 p.m.