Floating divide by zero with X compset

[gmodica@aer_com]

The X compset defines a null grid for the wave model, with x- and y- dimensions equal to zero (see scripts/ccm_utils/Case.template/config_grid.xml). So maybe it shouldn't come as a surprise when this appears eventually to result in a floating divide by zero error in dead_mod on the line below were 'dx' is calculated:   deg2rad = shr_const_pi / 180.0_R8
   re = shr_const_rearth

   allocate(gbuf(lsize,dead_grid_total))
   gbuf = -888.0_R8
   if (mype == 0) &
      write(logunit,*) subname,' Decomp is ',decomp_type,' lsize = ',lsize

   n=0
   dx = 360.0_R8/nxg * deg2rad
   do n = 1,lsize
      ig = mod((gindex(n)-1),nxg) + 1
      jg =     (gindex(n)-1)/nxg  + 1
...Can anyone suggest what is likely going on? Thanks.George(snippet from cesm.log file):dead_setNewGrid decomp 2d            2        2900           1          50
          59         116
 dead_setNewGrid decomp 2d            3        2900          51         100
          59         116
 dead_setNewGrid decomp 2d            1        2900          51         100
           1          58
 dead_setNewGrid decomp 2d            1        2900          26          50
           1         116
 dead_setNewGrid decomp 2d            2        2900          51          75
           1         116
 dead_setNewGrid decomp 2d            3        2900          76         100
           1         116
 dead_setNewGrid decomp 2d            1         828          19          36
           1          46
 dead_setNewGrid decomp 2d            2         828          37          54
           1          46
 dead_setNewGrid decomp 2d            3         828          55          72
           1          46
 dead_setNewGrid decomp 2d            1           0           1           0
           1           0
 dead_setNewGrid decomp 2d            2           0           1           0
           1           0
 dead_setNewGrid decomp 2d            3           0           1           0
           1           0
forrtl: error (73): floating divide by zero
Image              PC                Routine            Line        Source
cesm.exe           000000000085CDA5  Unknown               Unknown  Unknown
cesm.exe           000000000085A9C7  Unknown               Unknown  Unknown
cesm.exe           00000000007FF694  Unknown               Unknown  Unknown
cesm.exe           00000000007FF4A6  Unknown               Unknown  Unknown
cesm.exe           000000000078C3A6  Unknown               Unknown  Unknown
cesm.exe           0000000000796586  Unknown               Unknown  Unknown
libpthread.so.0    00002B41F6576370  Unknown               Unknown  Unknown
cesm.exe           00000000004A77F2  dead_mod_mp_dead_         234  dead_mod.F90
cesm.exe           00000000004A5537  wav_comp_mct_mp_w         206  wav_comp_mct.F90
cesm.exe           00000000004341DF  ccsm_comp_mod_mp_        1205  ccsm_comp_mod.F90
cesm.exe           0000000000436B33  MAIN__                     90  ccsm_driver.F90
cesm.exe           00000000004119DE  Unknown               Unknown  Unknown
libc.so.6          00002B41F67A4B35  Unknown               Unknown  Unknown
cesm.exe           00000000004118E9  Unknown               Unknown  Unknown