# DecomposePar filterPatches copyUniform cellDist functionality

 Register Blogs Members List Search Today's Posts Mark Forums Read

 June 6, 2008, 07:45 Dear Forum Users Wish you #1 Senior Member   Join Date: Mar 2009 Posts: 248 Rep Power: 11 Sponsored Links 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:
-----------------------------------   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      );  --------------------------------------
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:
--------------------------------------  // 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");                  }              }          }
---------------------------------------- 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: ---------------
forAll (oldPatchSizes, patchI)          {              if (!filterEmptyPatches || oldPatchSizes[patchI] > 0)              {                  curBoundaryAddressing[nPatches] = patchI;                    curPatchSizes[nPatches] = oldPatchSizes[patchI];                    curPatchStarts[nPatches] = oldPatchStarts[patchI];                    nPatches++;              }          }
------------------------ I hope to get some feedback from the experts. With Best Regards Jaswi

 June 10, 2008, 13:59 1) is a slight perturbation so #2 Super Moderator   Mattijs Janssens Join Date: Mar 2009 Posts: 1,419 Rep Power: 18 1) is a slight perturbation so on a perfectly aligned testcase cells go either into the 'top' processor or in the 'bottom' one and not one up, one down, one up etc. 2) it copies the 'uniform' subdirectory of a time. This contains any data which does not need to be decomposed. For data-distributed running this needs to be copied to all processor directories. 3) some applications and boundary conditions require all patches to be present on all processors (and in the same order), even if they locally have no faces. Some solvers and boundary conditions however don't care so there you could compress out the zero-sized boundaries.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Novak S. J. Elliott CFX 1 August 30, 2013 11:11 Peter Main CFD Forum 0 February 14, 2009 16:14 kian OpenFOAM 0 September 5, 2008 11:50 sergio OpenFOAM 9 March 13, 2008 06:18 nancy FLUENT 0 October 9, 2003 15:44