Default partition strategy seems broken (master)

We recently noticed that UG seems to have changed the partitioning strategy from release/2.6 to master.

  • As an example this is what 2.6 did with a sample grid:
ug_release2_6_paritioning
  • This is what master does:
ug_master_paritioning
  • It really gets bad when you use more processes, like in this example (a lot of long processor borders), master:
ug_partition_geothermal
  • Compare the partition with ParMETIS+UG which minimizes graph edge cuts (with master+ParMETIS user provided load balancing):
parmetis_partition_geothermal

Any idea if this is simply a bug? Or has some strategy been changed on purpose?

Edited by Timo Koch