return global element indices of the local region (excluding ghost points)
dm - the DMStag object
x - starting element index in first direction
y - starting element index in second direction
z - starting element index in third direction
m - element width in first direction
n - element width in second direction
p - element width in third direction
nExtrax - number of extra partial elements in first direction
nExtray - number of extra partial elements in second direction
nExtraz - number of extra partial elements in third direction
Arguments corresponding to higher dimensions are ignored for 1D and 2D grids. These arguments may be set to NULL in this case.
The number of extra partial elements is either 1 or 0. The value is 1 on right, top, and front non-periodic domain (“physical”) boundaries, in the x, y, and z directions respectively, and otherwise 0.