- make regionName an optional constructor parameter, which eliminates
a separate set of constructors and construction tables. Adjust
internals to treat a missing/empty regionName as a no-op.
- pass in fallback dictionary content via new IOdictionary constructor
with a pointer
ENH: further relax check for matching number of processor dirs
- if the "numberOfSubdomains" entry is missing (or even zero)
ignore checks of processor dirs as meaningless.
Within decomposeParDict, it is now possible to specify a different
decomposition method, methods coefficients or number of subdomains
for each region individually.
The top-level numberOfSubdomains remains mandatory, since this
specifies the number of domains for the entire simulation.
The individual regions may use the same number or fewer domains.
Any optional method coefficients can be specified in a general
"coeffs" entry or a method-specific one, eg "metisCoeffs".
For multiLevel, only the method-specific "multiLevelCoeffs" dictionary
is used, and is also mandatory.
----
ENH: shortcut specification for multiLevel.
In addition to the longer dictionary form, it is also possible to
use a shorter notation for multiLevel decomposition when the same
decomposition method applies to each level.
