get.UD {ctmcmove} | R Documentation |
Finds the stationary distribution (proportional utilization distribution) implied by a CTMC movement model with a given rate matrix.
get.UD(R,method="lu",maxiter, start, tol)
R |
Rate matrix with R[i,j] equal to the CTMC rate of movement from raster cell i to neighboring raster cell j. R[i,j]=0 implies that cells i and j are not first order neighbors. |
method |
Either "lu" (default) or "limit". See Details for a description of the two methods. |
start |
A value for the starting distribution for the 'limit' method. Defaults to 1/num. cells. Ignored for method='lu'. |
maxiter |
Total number of iterations for limit method if tolerance not reached first. Defaults to 100. Ignored for method='lu'. |
tol |
Value used to assess convergence for limit method. If max(abs(pi1-pi0))<tol, limit method has converged. Defaults to sqrt(.Machine$double.eps) |
This calculates the stationary distribution of the CTMC. If method="lu", then the method used is the method on pg. 455 of Harrod and Plemmons (1984). If method="limit", then the stationary distribution is approximated by brute-force simulation. If R is a sparse Matrix object, then sparse matrix methods are used, making this calculation extremely efficient.
Vector of the stationary distribution at each raster grid cell
Ephraim M. Hanks
Harrod, W. J. & Plemmons, R. J. Comparison of some direct methods for computing stationary distributions of Markov chains. SIAM Journal on Scientific and Statistical Computing, 1984, 5, 453-469
## For example code, do ## ## > help(ctmcMove)