# Region definitions

Regions are used to define sections of the domain. They may be either boxes, planes or points. They are used in defining initial and boundary conditions.

| Description | Type | Default
--- | --- | --- | ---
mfix.regions | Names given to regions. | Strings | None
regions.[region_name].lo | Low corner of physical region (physical, not index space) | Reals | 0 0 0
regions.[region_name].hi | High corner of physical region (physical, not index space) | Reals | 0 0 0

Below is an example for specifying two regions.

    mfix.regions  = full-domain   riser

    regions.full-domain.lo = 0.0000  0.0000  0.0000
    regions.full-domain.hi = 3.7584  0.2784  0.2784

    regions.riser.lo       = 0.0000  0.0000  0.0000
    regions.riser.hi       = 0.1000  0.2784  0.2784