Changes between Version 257 and Version 258 of doc/app/initialization_parameters

Timestamp:

Mar 27, 2015 9:25:33 AM (10 years ago)

Author:

raasch

Comment:

--

doc/app/initialization_parameters

@@ -957 +957 @@
       With parallel runs, starting from a certain grid level the data of the subdomains are possibly gathered on PE0 in order to allow for a further coarsening of the grid. The grid level for gathering can be manually set by [#mg_switch_to_pe0_level mg_switch_to_pe0_level].\\\\
       By default, Neumann boundary conditions for the perturbation pressure are used at all wall boundaries. In case of [#masking_method masking_method] = ''.TRUE.'', the masking method is used instead (i.e. the solver ''runs'' through the topography).\\\\
+'' 'multigrid_fast' ''\\\\
+      Same as '' 'multigrid' '' but optimized for better performance. Data along the {{{k}}} index (vertical direction) is sorted from alternate even and odd indices into two blocks of completely even and odd indices respectively, which allows vectorization on INTEL processors of loops in the red/black scheme. Additionally, topography flags are completely ignored (i.e. not used) in case of [#masking_method masking_method] switched on. On fine grid levels only even or odd data are send for the lateral ghost point exchange. Speedup of the multigrid solver for medium sized cases (1024*1024*192 gridpoints) can be about 40%.
 '' 'sor' ''\\\\
       Successive over relaxation method (SOR). The convergence of this iterative scheme is steered with the parameters [#omega_sor omega_sor], [#nsor_ini nsor_ini] and [#nsor nsor].\\