- expose the names of write and stopAt controls for reuse elsewhere and
provide a stopAtControls enum for 'unknown'
- track the requested number of sub-cycles (was previously a bool)
Original commit message:
------------------------
Parallel IO: New collated file format
When an OpenFOAM simulation runs in parallel, the data for decomposed fields and
mesh(es) has historically been stored in multiple files within separate
directories for each processor. Processor directories are named 'processorN',
where N is the processor number.
This commit introduces an alternative "collated" file format where the data for
each decomposed field (and mesh) is collated into a single file, which is
written and read on the master processor. The files are stored in a single
directory named 'processors'.
The new format produces significantly fewer files - one per field, instead of N
per field. For large parallel cases, this avoids the restriction on the number
of open files imposed by the operating system limits.
The file writing can be threaded allowing the simulation to continue running
while the data is being written to file. NFS (Network File System) is not
needed when using the the collated format and additionally, there is an option
to run without NFS with the original uncollated approach, known as
"masterUncollated".
The controls for the file handling are in the OptimisationSwitches of
etc/controlDict:
OptimisationSwitches
{
...
//- Parallel IO file handler
// uncollated (default), collated or masterUncollated
fileHandler uncollated;
//- collated: thread buffer size for queued file writes.
// If set to 0 or not sufficient for the file size threading is not used.
// Default: 2e9
maxThreadFileBufferSize 2e9;
//- masterUncollated: non-blocking buffer size.
// If the file exceeds this buffer size scheduled transfer is used.
// Default: 2e9
maxMasterFileBufferSize 2e9;
}
When using the collated file handling, memory is allocated for the data in the
thread. maxThreadFileBufferSize sets the maximum size of memory in bytes that
is allocated. If the data exceeds this size, the write does not use threading.
When using the masterUncollated file handling, non-blocking MPI communication
requires a sufficiently large memory buffer on the master node.
maxMasterFileBufferSize sets the maximum size in bytes of the buffer. If the
data exceeds this size, the system uses scheduled communication.
The installation defaults for the fileHandler choice, maxThreadFileBufferSize
and maxMasterFileBufferSize (set in etc/controlDict) can be over-ridden within
the case controlDict file, like other parameters. Additionally the fileHandler
can be set by:
- the "-fileHandler" command line argument;
- a FOAM_FILEHANDLER environment variable.
A foamFormatConvert utility allows users to convert files between the collated
and uncollated formats, e.g.
mpirun -np 2 foamFormatConvert -parallel -fileHandler uncollated
An example case demonstrating the file handling methods is provided in:
$FOAM_TUTORIALS/IO/fileHandling
The work was undertaken by Mattijs Janssens, in collaboration with Henry Weller.
- disable automatically upgrading copyrights in files since changes to
not automatically imply a change in copyright. Eg, fixing a typo in
comments, or changing a variable from 'loopI' to 'loopi' etc.
- this shifts responsibility away from caller to the individual writers
for knowing which file formats are supported and which file ending is
appropriate. When the writer receives the output format request,
it can elect to downgrade or otherwise adjust it to what it can
actually manage (eg, legacy vs xml vs xml-append).
But currently still just with legacy format backends.
- Remove the unused enums() method since it delivers wholly unreliable
results. It is not guaranteed to cover the full enumeration range,
but only the listed names.
- Remove the unused strings() method.
Duplicated functionality of the words(), but was never used.
- Change access of words() method from static to object.
Better code isolation. Permits the constructor to take over
as the single point of failure for bad input.
- Add values() method
- do not expose internal (HashTable) lookup since it makes it more
difficult to enforce constness and the implementation detail should
not be exposed. However leave toc() and sortedToc() for the interface.
STYLE: relocated NamedEnum under primitives (was containers)
- internal typedef as 'value_type' for some consistency with STL conventions
- make construct from UList explicit and provide corresponding
assignment operator.
- add construct,insert,set,assignment from FixedList.
This is convenient when dealing with things like edges or triFaces.
e.g. in tutorials/heatTransfer/buoyantSimpleFoam/externalCoupledCavity/0/T
hot
{
type externalCoupledTemperature;
commsDir "${FOAM_CASE}/comms";
file "data";
initByExternal yes;
log true;
value uniform 307.75; // 34.6 degC
}
Previously both 'file' and 'fileName' were used inconsistently in different
classes and given that there is no confusion or ambiguity introduced by using
the simpler 'file' rather than 'fileName' this change simplifies the use and
maintenance of OpenFOAM.
defined by functionObjects, e.g. wallHeatFlux, wallShearStress and yPlus.
Patch contributed by Bruno Santos
Resolves bug-report http://bugs.openfoam.org/view.php?id=2353
