compareFiles

Compare two MOAB .h5m files that represent the same mesh and emit a third file that carries the per-tag differences. The inputs must share GLOBAL_ID values on their elements, but their EntityHandle values can differ arbitrarily (e.g. because the two files were partitioned differently or saved by different MPI rank counts).

Output is an .h5m file derived from one of the inputs, with an extra tag per compared tag whose value is the difference (file1_value − file2_value) per entity.

Synopsis

mbcmpfiles -i <file1.h5m> -j <file2.h5m> -o <out.h5m> [options]

Binary name on disk is mbcmpfiles.

Options

Flag	Default	Description
-i <file1.h5m>, --input1 <file1.h5m>	—	First input mesh.
-j <file2.h5m>, --input2 <file2.h5m>	—	Second input mesh.
-o <out.h5m>, --outfile <out.h5m>	—	Output file with the per-tag difference fields added.
-n <tag>, --tagname <tag>	*(all tags)*	Restrict the comparison to a single tag. If unset, every tag found on both files is compared.
-d <dim>, --dimension <dim>	—	Topological dimension of entities to compare (0 vertices, 1 edges, 2 faces, 3 cells).

What it does

1. Loads both files independently.
2. Builds a map keyed on GLOBAL_ID so corresponding entities can be matched across the two files even when their EntityHandle values differ.
3. For each compared tag, computes file1 − file2 per entity and stores the result as a new tag on the chosen entity range.
4. Writes the result to <out.h5m>. The output preserves the topology of file 1 plus the new difference tags.

Examples

# Compare a single tag (e.g. a projected scalar field), only on cells
mbcmpfiles -i serial_run.h5m -j parallel_run.h5m  \
           -n AnalyticalSoln -d 2  -o diff.h5m
 
# Compare every shared tag, defaults to all entity dimensions
mbcmpfiles -i baseline.h5m -j candidate.h5m  -o all_diffs.h5m

After the run, open diff.h5m in your favorite viewer (ParaView via the MOAB plugin, VisIt) and look at the new difference tag — anywhere it's non-zero is where the two files disagree.

Notes

• The two files must reference the same mesh topology — same GLOBAL_ID set on the elements being compared. Entity counts must match per-dimension.
• Tags that are present on only one of the two files are skipped (with a warning).
• Tag types must match between the two files (e.g. you can't compare a DOUBLE tag in file 1 against an INTEGER tag of the same name in file 2).

See also

• `compareMaps` — for diffing remap-weight files in SCRIP format