- use std::string instead of c-string for the string constants
- centralize some definitions of resources into foamVersion.H
Now expose some of the hard-coded values used in foamEtcFiles()
so that they can be known or even overridden as required.
Relocate to src/OpenFOAM/include as a constant location.
- For compatibility, access to the old global names is provided via
macros
#define FOAMversion foamVersion::version
#define FOAMbuild foamVersion::build
#define FOAMbuildArch foamVersion::buildArch
- this isolation makes it easier to provide additional scoped methods
for dealing with version related information. Eg, printBuildInfo()
- centralizes IOobject handling and treatment of alternative locations.
If an alternative file location is specified, it will be used instead.
- provide decompositionMethod::canonicalName instead of using
"decomposeParDict" in various places.
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.
FoamFile
{
version 2.0;
format binary;
arch "LSB;label=32;scalar=64";
class vectorField;
object points;
}
There is otherwise no simple indication in any of the files as to the
sizes used (Int32 vs Int64, SP vs DP). This makes it difficult for the
end-user and also for any third-party consumers.
--
The architecture information contains three items in the following format:
(LSB|MSB);label=(32|64);scalar=(32|64)
- The endian value always appears first, without any leading space.
This make it trivial to check later. Either the first 3 letters (LSB
vs MSB) or even just the first letter ('L' vs 'M').
- Subsequent key=value pairs for 'label' and 'scalar' are separated
by semicolons. The ordering of label vs scalar is not specified.
Note that this 'arch' information is purely informational.
It is currently not used by the OpenFOAM input mechanism itself.
- regIOobject: don't re-register an unregister object on rename/assignment
- Hasher: split-off HasherInt with uint32_t specializations
- IOobject: writeBanner/writeDivider return Stream for easier chaining.
... also dropped some namespace bracketing while I was at it.
* new -srcDoc option to display doxygen-processed source code
* display standard options -help/-doc/-srcDoc at end of usage
* consolidate code when writing IOobject headers
* drop writeLogbanner and add optional bool to writeBanner
* minor formatting changes
