Ph. Hauschildt et al., CONVERGENCE PROPERTIES OF THE ACCELERATED LAMBDA-ITERATION METHOD FORTHE SOLUTION OF RADIATIVE-TRANSFER PROBLEMS, Journal of quantitative spectroscopy & radiative transfer, 51(6), 1994, pp. 875-891
We investigate the convergence properties and the computational speed
of the accelerated LAMBDA-iteration method for the solution of a wide
variety of radiative transfer problems. The formal solution of the tra
nsfer equation is done using the short characteristics method. As the
approximate LAMBDA-operator we use bands or the discretized LAMBDA-ope
rator and derive the formulae for computing operators with arbitrary b
andwidth. We define the optimum bandwidth of the approximate LAMBDA-op
erator as the bandwidth for which the CPU time used for the solution o
f any particular radiative transfer problems is minimum. The radiative
transfer equation is solved for a number of continuum and line transf
er problems in spherical symmetry and for static to very rapidly expan
ding media. We find the optimum bandwidth is around 5-15 for workstati
on class computers whereas it is around 1-2 for supercomputers.