The surface mesh setPoints function resets the points without caching the old
points or swept areas so is the equivalent of the polyMesh::setPoints rather
than movePoints.
Replaces MeshObject, providing a formalised method for creating demand-driven
mesh objects, optionally supporting update functions called by the mesh
following mesh changes.
Class
Foam::DemandDrivenMeshObject
Description
Templated abstract base-class for demand-driven mesh objects used to
automate their allocation to the mesh database and the mesh-modifier
event-loop.
DemandDrivenMeshObject is templated on the type of mesh it is allocated
to, the type of the mesh object (TopologicalMeshObject, GeometricMeshObject,
MoveableMeshObject, DistributeableMeshObject, UpdateableMeshObject) and the
type of the actual object it is created for example:
\verbatim
class leastSquaresVectors
:
public DemandDrivenMeshObject
<
fvMesh,
MoveableMeshObject,
leastSquaresVectors
>
{
.
.
.
//- Delete the least square vectors when the mesh moves
virtual bool movePoints();
};
\endverbatim
MeshObject types:
- TopologicalMeshObject: mesh object to be deleted on topology change
- GeometricMeshObject: mesh object to be deleted on geometry change
- MoveableMeshObject: mesh object to be updated in movePoints
- UpdateableMeshObject: mesh object to be updated in topoChange or
movePoints
- PatchMeshObject: mesh object to be additionally updated patch changes
DemandDrivenMeshObject should always be constructed and accessed via the New
methods provided so that they are held and maintained by the objectRegistry.
To ensure this use constructors of the concrete derived types should be
private or protected and friendship with the DemandDrivenMeshObject
base-class declared so that the New functions can call the the constructors.
Additionally the mesh-object types (TopologicalMeshObject, GeometricMeshObject,
MoveableMeshObject, DistributeableMeshObject, UpdateableMeshObject) can now be
used as mix-in types for normally allocated objects providing the same interface
to mesh-change update functions, see the Fickian fluid
thermophysicalTransportModel or anisotropic solid thermophysicalTransportModel.
This new approach to adding mesh-update functions to classes will be applied to
other existing classes and future developments to simplify the support and
maintenance of run-time mesh changes, in particular mesh refinement/unrefinement
and mesh-to-mesh mapping.
The FOAM file format has not changed from version 2.0 in many years and so there
is no longer a need for the 'version' entry in the FoamFile header to be
required and to reduce unnecessary clutter it is now optional, defaulting to the
current file format 2.0.
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.
