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Chris, Sounds like you are having trouble composing WND from the components). Not sure why without seeing what your grid navigation and size is since the function you show works for me using current ETA data. Could be a problem with the stack size. Are these big grids (kxky)? If so, it could be that you don't have enough memory to load in all the grids (remember that you probably have a conversion from dwpc=sub(dwpk,273.15) and vecr(urel,vrel), before the mixr() computation and the resulting output grid. Presumably you have UREL and VREL at 925mb. What happens if you try using sdiv(mixr(dwpc,pres),vecr(urel,vrel))? If the result works with smaller grids, then you may have to do the computation in smaller pieces using gddiag. Similarly, your tmpc calculation is also undergoing a tmpc=tmpk-273.15. Otherwise, we'd have to recompile with a bigger heap defined for LLMDGG in $GEMPAK/include/GEMPRM.PRM Steve Chiswell >From: Chris Hennon <address@hidden> >Organization: UCAR/Unidata >Keywords: 200206182105.g5IL5L617501 >Steve - > >Can you tell me why these arguments: > >gddiag << EOF > GDFILE = /home/chennon/data/grib/mdivrepo_1998.grd > GDOUTF = /home/chennon/data/grib/mdiv_1998.grd > GFUNC = sdiv(mixr(dwpc,pres),wnd) > GDATTIM = 980501/0000 > GLEVEL = 925 > GVCORD = PRES > GRDNAM = MDIV > GPACK = >r > >e >EOF > >produce this error: > >[DG -7] Input grid WND ^980501/0000 @925 %PRES in SDIV cannot be found. > >I also have this problem when I try to add three scalar fields, for >example: > >add(add(tmpc+1,tmpc+2),tmpc+3) > >All grids that I need to compute moisture convergence exist in the >mdivrepo grid file. It isn't liking the nesting for some reason - I have >used this technique successfully in the past. I'm using version >5.6.e.1. Thanks. > >Chris > >================================================ >| Chris Hennon Ohio State University | >| Tropical Meteorology address@hidden | >| | >| Dept of Geography Office: 1155 Derby Hall | >| 1036 Derby Hall Phone : (614) 292-2704 | >| Columbus, OH 43210 Fax : (614) 292-6213 | >================================================ >