[jaswi]

Dear Forum Users

Wish you all good FOAMing today :-)

Need some help to figure out the proper usage of decomposePar. Here are some related queries:

1) What is the significance of "delta" being used for the geometrical decomposition options. In the constructor of geomDecomp a tensor is being defined this way:

<pre>
-----------------------------------
scalar d = 1 - 0.5*delta_*delta_;
scalar d2 = sqr(d);

scalar a = delta_;
scalar a2 = sqr(a);

rotDelta_ = tensor
(
d2, -a*d, a,
a*d - a2*d, a*a2 + d2, -2*a*d,
a*d2 + a2, a*d - a2*d, d2 - a2
);
--------------------------------------
</pre>

which is later used to do a rotation of pointField in the derived classes simpleGeomDecomp and hierarchGeomDecomp. This operation is done in the
labelList decompose(const pointField&); member function of the respective derived classes
.....
....
pointField rotatedPoints = rotDelta_ & points;
....
...

2) what is the effect of the option -copyUniform.
The code corresponding to this option is in
decomposePar.c (lines 575 - 600). This action is done when this option is selected:
<pre>
--------------------------------------
// Any non-decomposed data to copy?
if (uniformDir.size() > 0)
{
if (copyUniform || mesh.distributed())
{
cp(uniformDir, processorDb.timePath()/"uniform");
}
else
{
fileName timePath = processorDb.timePath();

if (timePath[0] != '/')
{
// Adapt uniformDir and timePath to be relative paths.
string parentPath(string("..")/"..");
fileName currentDir(cwd());
chDir(timePath);
ln(parentPath/uniformDir, parentPath/timePath/"uniform");
chDir(currentDir);
}
else
{
ln(uniformDir, timePath/"uniform");
}
}
}

</pre>
----------------------------------------

but I couldn't understand it , so please comment on this one .

3) the last query is of similar nature regarding the option -filterPatches. This option is passed on to the mesh.decomposeMesh(filterPatches); and
in decomposeMesh.C (lines 634-647) the corresponding code is:
---------------
<pre>

forAll (oldPatchSizes, patchI)
{
if (!filterEmptyPatches || oldPatchSizes[patchI] > 0)
{
curBoundaryAddressing[nPatches] = patchI;

curPatchSizes[nPatches] = oldPatchSizes[patchI];

curPatchStarts[nPatches] = oldPatchStarts[patchI];

nPatches++;
}
}
</pre>
------------------------

I hope to get some feedback from the experts.

With Best Regards
Jaswi