SUE: Stochastic User Equilibrium

In MartinLHazelton/transportation: What the Package Does (One Line, Title Case)

Stochastic User Equilibrium

Description

This function calculates stochastic user equilibrium (SUE) using the method of successive weighted averages. Output is a list of SUE route flows x and corresponding path costs u.

Usage

SUE(
  ODdemand,
  ODpair,
  A,
  Alpha,
  Beta,
  pow = 4,
  RUM = "logit",
  x.ini = NULL,
  theta = 1,
  tune.d = 1,
  tol = 1e-04,
  verbose = F
)

Arguments

ODdemand	Vector of origin-destination (OD) travel demands
ODpair	Vector indicating the OD pair serviced by each route (ordered by columns of the path-link incidence matrix, A).
A	Path-link incidence matrix
Alpha	Vector of free flow travel time parameters for each link
Beta	Vector of capacity parameters for each link
pow	Polynomial order of cost function for each link. Defaults to 4.
RUM	Choice of random utility model. Can be "logit" (the default) or "probit".
x.ini	Initialization route flows for SUE algorithm (optional).
theta	A dispersion parameter. For the logit model, a single value specifying the logit parameter. For the probit model, a vector of standard deviations for the individual link cost errors. Defaults to 1.
tune.d	Tuning parameter; tune.d=0 corresponds to the basic method of successive averages. Defaults to 1.
tol	Tolerance for convergence assessment (measured as route mean squared difference between current flow vector and the search direction). Defaults of 1e-4.
verbose	Should progress of algorithm be printed out? Defaults to FALSE.

Value

Output is a list of SUE route flows x, corresponding path costs u, and corresponding link cost k.

Examples

A <- matrix(c(0,1,0,0,1,0,0,0,0,1,1,0,0,0,1,0,0,0,0,1,1,0,0,0,0,0,0,1),ncol=4,byrow=T) 
Alpha <- rep(10,7)
Beta <- rep(50,7)
pow <- rep(4,7)
ODpair <- c(1,1,2,2)
ODdemand <- c(50,50)
theta <- 0.7
SUE(ODdemand,ODpair,A=A,Alpha=Alpha,Beta=Beta,pow=pow,theta=theta,verbose=F)

MartinLHazelton/transportation documentation built on Aug. 5, 2023, 10:28 a.m.