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.
Updated the tetrahedron and triangle classes to use the barycentric
primitives. Removed duplicate code for generating random positions in
tets and tris, and fixed bug in tri random position.
now possible with level-sets as well as planes. Removed tetPoints class
as this wasn't really used anywhere except for the old tet-cutting
routines. Restored tetPointRef.H to be consistent with other primitive
shapes. Re-wrote tet-overlap mapping in terms of the new cutting.
except turbulence and lagrangian which will also be updated shortly.
For example in the nonNewtonianIcoFoam offsetCylinder tutorial the viscosity
model coefficients may be specified in the corresponding "<type>Coeffs"
sub-dictionary:
transportModel CrossPowerLaw;
CrossPowerLawCoeffs
{
nu0 [0 2 -1 0 0 0 0] 0.01;
nuInf [0 2 -1 0 0 0 0] 10;
m [0 0 1 0 0 0 0] 0.4;
n [0 0 0 0 0 0 0] 3;
}
BirdCarreauCoeffs
{
nu0 [0 2 -1 0 0 0 0] 1e-06;
nuInf [0 2 -1 0 0 0 0] 1e-06;
k [0 0 1 0 0 0 0] 0;
n [0 0 0 0 0 0 0] 1;
}
which allows a quick change between models, or using the simpler
transportModel CrossPowerLaw;
nu0 [0 2 -1 0 0 0 0] 0.01;
nuInf [0 2 -1 0 0 0 0] 10;
m [0 0 1 0 0 0 0] 0.4;
n [0 0 0 0 0 0 0] 3;
if quick switching between models is not required.
To support this more convenient parameter specification the inconsistent
specification of seedSampleSet in the streamLine and wallBoundedStreamLine
functionObjects had to be corrected from
// Seeding method.
seedSampleSet uniform; //cloud; //triSurfaceMeshPointSet;
uniformCoeffs
{
type uniform;
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
to the simpler
// Seeding method.
seedSampleSet
{
type uniform;
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
which also support the "<type>Coeffs" form
// Seeding method.
seedSampleSet
{
type uniform;
uniformCoeffs
{
axis x; //distance;
// Note: tracks slightly offset so as not to be on a face
start (-1.001 -0.05 0.0011);
end (-1.001 -0.05 1.0011);
nPoints 20;
}
}
By default snappyHexMesh writes files relating to the hex-splitting process into
the polyMesh directory: cellLevel level0Edge pointLevel surfaceIndex
but by setting the noRefinement flag:
writeFlags
(
noRefinement
.
.
.
);
these optional files which are generally not needed are not written.
If you run the three stages of snappyHexMesh separately or run a dynamic mesh
solver supporting refinement and unrefinement these files are needed
and "noRefinement" should not be set.
unless the blockMeshDict is in the polyMesh directory or the "-noClean" option
is specified.
This avoids problems running snappyHexMesh without first clearing files from
polyMesh which interfere with the operation of snappyHexMesh.
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.
For example, to mesh a sphere with a single block the geometry is defined in the
blockMeshDict as a searchableSurface:
geometry
{
sphere
{
type searchableSphere;
centre (0 0 0);
radius 1;
}
}
The vertices, block topology and curved edges are defined in the usual
way, for example
v 0.5773502;
mv -0.5773502;
a 0.7071067;
ma -0.7071067;
vertices
(
($mv $mv $mv)
( $v $mv $mv)
( $v $v $mv)
($mv $v $mv)
($mv $mv $v)
( $v $mv $v)
( $v $v $v)
($mv $v $v)
);
blocks
(
hex (0 1 2 3 4 5 6 7) (10 10 10) simpleGrading (1 1 1)
);
edges
(
arc 0 1 (0 $ma $ma)
arc 2 3 (0 $a $ma)
arc 6 7 (0 $a $a)
arc 4 5 (0 $ma $a)
arc 0 3 ($ma 0 $ma)
arc 1 2 ($a 0 $ma)
arc 5 6 ($a 0 $a)
arc 4 7 ($ma 0 $a)
arc 0 4 ($ma $ma 0)
arc 1 5 ($a $ma 0)
arc 2 6 ($a $a 0)
arc 3 7 ($ma $a 0)
);
which will produce a mesh in which the block edges conform to the sphere
but the faces of the block lie somewhere between the original cube and
the spherical surface which is a consequence of the edge-based
transfinite interpolation.
Now the projection of the block faces to the geometry specified above
can also be specified:
faces
(
project (0 4 7 3) sphere
project (2 6 5 1) sphere
project (1 5 4 0) sphere
project (3 7 6 2) sphere
project (0 3 2 1) sphere
project (4 5 6 7) sphere
);
which produces a mesh that actually conforms to the sphere.
See OpenFOAM-dev/tutorials/mesh/blockMesh/sphere
This functionality is experimental and will undergo further development
and generalization in the future to support more complex surfaces,
feature edge specification and extraction etc. Please get involved if
you would like to see blockMesh become a more flexible block-structured
mesher.
Henry G. Weller, CFD Direct.
blockMesh -help
Usage: blockMesh [OPTIONS]
options:
-blockTopology write block edges and centres as .obj files
-case <dir> specify alternate case directory, default is the cwd
-dict <file> specify alternative dictionary for the blockMesh description
-noFunctionObjects
do not execute functionObjects
-region <name> specify alternative mesh region
-srcDoc display source code in browser
-doc display application documentation in browser
-help print the usage
Block description
For a given block, the correspondence between the ordering of
vertex labels and face labels is shown below.
For vertex numbering in the sequence 0 to 7 (block, centre):
faces 0 (f0) and 1 are left and right, respectively;
faces 2 and 3 are bottom and top;
and faces 4 and 5 are front the back:
4 ---- 5
f3 |\ |\ f5
| | 7 ---- 6 \
| 0 |--- 1 | \
| \| \| f4
f2 3 ---- 2
f0 ----- f1
Using: OpenFOAM-dev (see www.OpenFOAM.org)
Build: dev-9d3f407fc741
to have the prefix 'write' rather than 'output'
So outputTime() -> writeTime()
but 'outputTime()' is still supported for backward-compatibility.
Also removed the redundant secondary-writing functionality from Time
which has been superseded by the 'writeRegisteredObject' functionObject.
These new names are more consistent and logical because:
primitiveField():
primitiveFieldRef():
Provides low-level access to the Field<Type> (primitive field)
without dimension or mesh-consistency checking. This should only be
used in the low-level functions where dimensional consistency is
ensured by careful programming and computational efficiency is
paramount.
internalField():
internalFieldRef():
Provides access to the DimensionedField<Type, GeoMesh> of values on
the internal mesh-type for which the GeometricField is defined and
supports dimension and checking and mesh-consistency checking.
Non-const access to the internal field now obtained from a specifically
named access function consistent with the new names for non-canst access
to the boundary field boundaryFieldRef() and dimensioned internal field
dimensionedInternalFieldRef().
See also commit a4e2afa4b3
Given that the type of the dimensioned internal field is encapsulated in
the GeometricField class the name need not include "Field"; the type
name is "Internal" so
volScalarField::DimensionedInternalField -> volScalarField::Internal
In addition to the ".dimensionedInternalField()" access function the
simpler "()" de-reference operator is also provided to greatly simplify
FV equation source term expressions which need not evaluate boundary
conditions. To demonstrate this kEpsilon.C has been updated to use
dimensioned internal field expressions in the k and epsilon equation
source terms.
Contributed by Mattijs Janssens.
1. Any non-blocking data exchange needs to know in advance the sizes to
receive so it can size the buffer. For "halo" exchanges this is not
a problem since the sizes are known in advance but or all other data
exchanges these sizes need to be exchanged in advance.
This was previously done by having all processors send the sizes of data to
send to the master and send it back such that all processors
- had the same information
- all could work out who was sending what to where and hence what needed to
be received.
This is now changed such that we only send the size to the
destination processor (instead of to all as previously). This means
that
- the list of sizes to send is now of size nProcs v.s. nProcs*nProcs before
- we cut out the route to the master and back by using a native MPI
call
It causes a small change to the API of exchange and PstreamBuffers -
they now return the sizes of the local buffers only (a labelList) and
not the sizes of the buffers on all processors (labelListList)
2. Reversing the order of the way in which the sending is done when
scattering information from the master processor to the other
processors. This is done in a tree like fashion. Each processor has a
set of processors to receive from/ send to. When receiving it will
first receive from the processors with the least amount of
sub-processors (i.e. the ones which return first). When sending it
needs to do the opposite: start sending to the processor with the
most amount of sub-tree since this is the critical path.
Patch contributed by Bruno Santos:
- "etc/config.sh/CGAL":
- Indented the contents of the recently added if block.
- Added comment about using system versions.
- Library paths are now only added if the respective version is not "boost-system" and "cgal-system".
- "src/renumber/Allwmake":
It now relies on the previous file to get the version for
Boost (the same way as in "makeCGAL"). This is so that it will also
build "SloanRenumber" if "boost_version" is set to "boost-system".
- "applications/utilities/mesh/generation/Allwmake":
It now also relies on the script "config.sh/CGAL" to get the
version for CGAL. If "cgal_version" is set to "cgal-system", it
will now also build "foamy*Mesh" utilities and respective
libraries.
Resolves report http://www.openfoam.org/mantisbt/view.php?id=1232
