GGEN_Remarks:

In the simplest case, the number designated by "NBL" in each GGEN namelist is simply the total number of zones in the global problem domain along the appropriate coordinate axis. In a parallel calculation, the following equalities would apply:

1. NBL(GGEN1) = NTILES(1) x I_ZONES
2. NBL(GGEN2) = NTILES(2) x J_ZONES
3. NBL(GGEN3) = NTILES(3) x K_ZONES

ZEUS-MP has the ability to adopt ratioed zoning according to parameters such as IGRID, X(1,2,3)RAT, and DX(1,2,3)MIN. A given zoning prescription (including uniforming zoning) can be applied to a sub-portion of the global axis, in which case NBL becomes the number of zones over which a given zoning prescription is employed. For example, if we wished to use uniform zoning along the inner half of the 1-axis and ratioed zoning along the outer half, our copy of ZMP_INP would contain two consecutive entries for GGEN1, in which the grid parameters for each block are chosen appropriately. Notice that in the first instance of GGEN1, the parameter LGRID is set to .FALSE., whereas in the second instance it is .TRUE. The value of .TRUE. tells ZEUS-MP that no further blocks of zones are to be read for this coordinate axis.