Example comm split

Add an example to show that Chameleon can be used with custom MPI communicators (different from MPI_COMM_WORLD).

Two different algorithms (potrf and getrf_nopiv) are called at the same time on two different communicators A (0, 2) and B (1, 3).

added 2 commits

• b81b5b64 - Fix example lapack_to_chameleon step7: descB instead of descA in the plrnt_cpu function
• 482011cb - Add an example + utest for using MPI subcommunicators

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approved this merge request

added 5 commits

• 482011cb...9b9b6d1a - 3 commits from branch solverstack:master
• bd7d2bf0 - Fix example lapack_to_chameleon step7: descB instead of descA in the plrnt_cpu function
• 16b7c4ef - Add an example + utest for using MPI subcommunicators

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enabled an automatic merge when the pipeline for 16b7c4ef succeeds

merged

mentioned in commit f7f321ab

changed milestone to %Chameleon 1.3.0