Hello Hee Il,
All the utility codes (hdf5_merge, hdf5_extract, & hdf5_double_to_single) could be built on ET and could do someting e.g. merging chunked data but they don't seem to match with current Carpet HDF5 format. I couldn't open the combined file with Visit.
Did you perhaps try the following (or similar)?
hdf5_merge gxx.file_0.h5 gxx.file_1.h5 gxx.h5
That will not work since hdf5_merge does not adjust the field IOProcs in the files which tells the VisIt reader how many files to look for. What works is eg.
hdf5_merge restart1/gxx.file_0.h5 restart2/gxx.file_0.h5 combined/gxx.file_0.h5
Instead you can use
hdf5_slicer --match '.*' --out3d-cube gxx.file_0.h5 gxx.file_1.h5 gxx.h5
from carpetiohdf5. Neither one does any merging of patches, they simply copy datasets from one file to he other.
Yours, Roland