Detailed description of the normalization of the transport equations employed in TRINITY: trin_norm.pdf

The transport equations are stiff, nonlinear partial differential equations. In order to take the large time steps desired of our multiscale scheme, we must treat them implicitly. We allow for a general, single-step time discretization, but we primarily use first-order backwards differences for steady-state systems and second order (multi-step) backwards differences for time-dependent systems. An adaptive time step is employed, allowing for accurate time evolution with large time steps. The nonlinear terms are treated implicitly by linearizing them using a standard, multi-iteration Newton's method. A detailed description of the equations solved and numerical algorithm employed by TRINITY is given here: short, long (see Ch. 7)

Input parameter namelists:
&geometry, &species, &time, &fluxes, &init, &sources, &physics.

Output files:
.nt, .plot, .info, .tmp, .balance, .pwr, .iter, .time, .geo