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openfoam/src/parallel/decompositionMethods/scotchDecomp/scotchDecomp.C
2010-01-15 17:14:42 +00:00

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C

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 1991-2009 OpenCFD Ltd.
\\/ M anipulation |
-------------------------------------------------------------------------------
License
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under the terms of the GNU General Public License as published by the
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From scotch forum:
By: Francois PELLEGRINI RE: Graph mapping 'strategy' string [ reply ]
2008-08-22 10:09 Strategy handling in Scotch is a bit tricky. In order
not to be confused, you must have a clear view of how they are built.
Here are some rules:
1- Strategies are made up of "methods" which are combined by means of
"operators".
2- A method is of the form "m{param=value,param=value,...}", where "m"
is a single character (this is your first error: "f" is a method name,
not a parameter name).
3- There exist different sort of strategies : bipartitioning strategies,
mapping strategies, ordering strategies, which cannot be mixed. For
instance, you cannot build a bipartitioning strategy and feed it to a
mapping method (this is your second error).
To use the "mapCompute" routine, you must create a mapping strategy, not
a bipartitioning one, and so use stratGraphMap() and not
stratGraphBipart(). Your mapping strategy should however be based on the
"recursive bipartitioning" method ("b"). For instance, a simple (and
hence not very efficient) mapping strategy can be :
"b{sep=f}"
which computes mappings with the recursive bipartitioning method "b",
this latter using the Fiduccia-Mattheyses method "f" to compute its
separators.
If you want an exact partition (see your previous post), try
"b{sep=fx}".
However, these strategies are not the most efficient, as they do not
make use of the multi-level framework.
To use the multi-level framework, try for instance:
"b{sep=m{vert=100,low=h,asc=f}x}"
The current default mapping strategy in Scotch can be seen by using the
"-vs" option of program gmap. It is, to date:
b
{
job=t,
map=t,
poli=S,
sep=
(
m
{
asc=b
{
bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
org=f{move=80,pass=-1,bal=0.005},
width=3
},
low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
type=h,
vert=80,
rat=0.8
}
| m
{
asc=b
{
bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
org=f{move=80,pass=-1,bal=0.005},
width=3
},
low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
type=h,
vert=80,
rat=0.8
}
)
}
\*---------------------------------------------------------------------------*/
#include "scotchDecomp.H"
#include "addToRunTimeSelectionTable.H"
#include "floatScalar.H"
#include "Time.H"
#include "cyclicPolyPatch.H"
#include "OFstream.H"
extern "C"
{
#include "scotch.h"
}
// Hack: scotch generates floating point errors so need to switch of error
// trapping!
#if defined(linux) || defined(linuxAMD64) || defined(linuxIA64)
# define LINUX
#endif
#if defined(LINUX) && defined(__GNUC__)
# define LINUX_GNUC
#endif
#ifdef LINUX_GNUC
# ifndef __USE_GNU
# define __USE_GNU
# endif
# include <fenv.h>
#endif
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
defineTypeNameAndDebug(scotchDecomp, 0);
addToRunTimeSelectionTable
(
decompositionMethod,
scotchDecomp,
dictionaryMesh
);
}
// * * * * * * * * * * * * * Private Member Functions * * * * * * * * * * * //
void Foam::scotchDecomp::check(const int retVal, const char* str)
{
if (retVal)
{
FatalErrorIn("scotchDecomp::decompose(..)")
<< "Call to scotch routine " << str << " failed."
<< exit(FatalError);
}
}
// Call scotch with options from dictionary.
Foam::label Foam::scotchDecomp::decompose
(
const List<int>& adjncy,
const List<int>& xadj,
const scalarField& cWeights,
List<int>& finalDecomp
)
{
// Dump graph
if (decompositionDict_.found("scotchCoeffs"))
{
const dictionary& scotchCoeffs =
decompositionDict_.subDict("scotchCoeffs");
if (scotchCoeffs.found("writeGraph"))
{
Switch writeGraph(scotchCoeffs.lookup("writeGraph"));
if (writeGraph)
{
OFstream str(mesh_.time().path() / mesh_.name() + ".grf");
Info<< "Dumping Scotch graph file to " << str.name() << endl
<< "Use this in combination with gpart." << endl;
label version = 0;
str << version << nl;
// Numer of vertices
str << xadj.size()-1 << ' ' << adjncy.size() << nl;
// Numbering starts from 0
label baseval = 0;
// Has weights?
label hasEdgeWeights = 0;
label hasVertexWeights = 0;
label numericflag = 10*hasEdgeWeights+hasVertexWeights;
str << baseval << ' ' << numericflag << nl;
for (label cellI = 0; cellI < xadj.size()-1; cellI++)
{
label start = xadj[cellI];
label end = xadj[cellI+1];
str << end-start;
for (label i = start; i < end; i++)
{
str << ' ' << adjncy[i];
}
str << nl;
}
}
}
}
// Strategy
// ~~~~~~~~
// Default.
SCOTCH_Strat stradat;
check(SCOTCH_stratInit(&stradat), "SCOTCH_stratInit");
if (decompositionDict_.found("scotchCoeffs"))
{
const dictionary& scotchCoeffs =
decompositionDict_.subDict("scotchCoeffs");
string strategy;
if (scotchCoeffs.readIfPresent("strategy", strategy))
{
if (debug)
{
Info<< "scotchDecomp : Using strategy " << strategy << endl;
}
SCOTCH_stratGraphMap(&stradat, strategy.c_str());
//fprintf(stdout, "S\tStrat=");
//SCOTCH_stratSave(&stradat, stdout);
//fprintf(stdout, "\n");
}
}
// Graph
// ~~~~~
List<int> velotab;
// Check for externally provided cellweights and if so initialise weights
scalar maxWeights = gMax(cWeights);
if (cWeights.size() > 0)
{
if (cWeights.size() != xadj.size()-1)
{
FatalErrorIn
(
"scotchDecomp::decompose"
"(const pointField&, const scalarField&)"
) << "Number of cell weights " << cWeights.size()
<< " does not equal number of cells " << xadj.size()-1
<< exit(FatalError);
}
// Convert to integers.
velotab.setSize(cWeights.size());
forAll(velotab, i)
{
velotab[i] = int(1000000*cWeights[i]/maxWeights);
}
}
SCOTCH_Graph grafdat;
check(SCOTCH_graphInit(&grafdat), "SCOTCH_graphInit");
check
(
SCOTCH_graphBuild
(
&grafdat,
0, // baseval, c-style numbering
xadj.size()-1, // vertnbr, nCells
xadj.begin(), // verttab, start index per cell into adjncy
&xadj[1], // vendtab, end index ,,
velotab.begin(), // velotab, vertex weights
NULL, // vlbltab
adjncy.size(), // edgenbr, number of arcs
adjncy.begin(), // edgetab
NULL // edlotab, edge weights
),
"SCOTCH_graphBuild"
);
check(SCOTCH_graphCheck(&grafdat), "SCOTCH_graphCheck");
// Architecture
// ~~~~~~~~~~~~
// (fully connected network topology since using switch)
SCOTCH_Arch archdat;
check(SCOTCH_archInit(&archdat), "SCOTCH_archInit");
List<label> processorWeights;
if (decompositionDict_.found("scotchCoeffs"))
{
const dictionary& scotchCoeffs =
decompositionDict_.subDict("scotchCoeffs");
scotchCoeffs.readIfPresent("processorWeights", processorWeights);
}
if (processorWeights.size())
{
if (debug)
{
Info<< "scotchDecomp : Using procesor weights " << processorWeights
<< endl;
}
check
(
SCOTCH_archCmpltw(&archdat, nProcessors_, processorWeights.begin()),
"SCOTCH_archCmpltw"
);
}
else
{
check
(
SCOTCH_archCmplt(&archdat, nProcessors_),
"SCOTCH_archCmplt"
);
}
//SCOTCH_Mapping mapdat;
//SCOTCH_graphMapInit(&grafdat, &mapdat, &archdat, NULL);
//SCOTCH_graphMapCompute(&grafdat, &mapdat, &stradat); /* Perform mapping */
//SCOTCH_graphMapExit(&grafdat, &mapdat);
// Hack:switch off fpu error trapping
# ifdef LINUX_GNUC
int oldExcepts = fedisableexcept
(
FE_DIVBYZERO
| FE_INVALID
| FE_OVERFLOW
);
# endif
finalDecomp.setSize(xadj.size()-1);
finalDecomp = 0;
check
(
SCOTCH_graphMap
(
&grafdat,
&archdat,
&stradat, // const SCOTCH_Strat *
finalDecomp.begin() // parttab
),
"SCOTCH_graphMap"
);
# ifdef LINUX_GNUC
feenableexcept(oldExcepts);
# endif
//finalDecomp.setSize(xadj.size()-1);
//check
//(
// SCOTCH_graphPart
// (
// &grafdat,
// nProcessors_, // partnbr
// &stradat, // const SCOTCH_Strat *
// finalDecomp.begin() // parttab
// ),
// "SCOTCH_graphPart"
//);
// Release storage for graph
SCOTCH_graphExit(&grafdat);
// Release storage for strategy
SCOTCH_stratExit(&stradat);
// Release storage for network topology
SCOTCH_archExit(&archdat);
return 0;
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::scotchDecomp::scotchDecomp
(
const dictionary& decompositionDict,
const polyMesh& mesh
)
:
decompositionMethod(decompositionDict),
mesh_(mesh)
{}
// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //
Foam::labelList Foam::scotchDecomp::decompose
(
const pointField& points,
const scalarField& pointWeights
)
{
if (points.size() != mesh_.nCells())
{
FatalErrorIn
(
"scotchDecomp::decompose(const pointField&, const scalarField&)"
)
<< "Can use this decomposition method only for the whole mesh"
<< endl
<< "and supply one coordinate (cellCentre) for every cell." << endl
<< "The number of coordinates " << points.size() << endl
<< "The number of cells in the mesh " << mesh_.nCells()
<< exit(FatalError);
}
// Make Metis CSR (Compressed Storage Format) storage
// adjncy : contains neighbours (= edges in graph)
// xadj(celli) : start of information in adjncy for celli
List<int> adjncy;
List<int> xadj;
calcCSR(mesh_, adjncy, xadj);
// Decompose using default weights
List<int> finalDecomp;
decompose(adjncy, xadj, pointWeights, finalDecomp);
// Copy back to labelList
labelList decomp(finalDecomp.size());
forAll(decomp, i)
{
decomp[i] = finalDecomp[i];
}
return decomp;
}
Foam::labelList Foam::scotchDecomp::decompose
(
const labelList& agglom,
const pointField& agglomPoints,
const scalarField& pointWeights
)
{
if (agglom.size() != mesh_.nCells())
{
FatalErrorIn
(
"parMetisDecomp::decompose(const labelList&, const pointField&)"
) << "Size of cell-to-coarse map " << agglom.size()
<< " differs from number of cells in mesh " << mesh_.nCells()
<< exit(FatalError);
}
// Make Metis CSR (Compressed Storage Format) storage
// adjncy : contains neighbours (= edges in graph)
// xadj(celli) : start of information in adjncy for celli
List<int> adjncy;
List<int> xadj;
{
// Get cellCells on coarse mesh.
labelListList cellCells;
calcCellCells
(
mesh_,
agglom,
agglomPoints.size(),
cellCells
);
calcCSR(cellCells, adjncy, xadj);
}
// Decompose using weights
List<int> finalDecomp;
decompose(adjncy, xadj, pointWeights, finalDecomp);
// Rework back into decomposition for original mesh_
labelList fineDistribution(agglom.size());
forAll(fineDistribution, i)
{
fineDistribution[i] = finalDecomp[agglom[i]];
}
return fineDistribution;
}
Foam::labelList Foam::scotchDecomp::decompose
(
const labelListList& globalCellCells,
const pointField& cellCentres,
const scalarField& cWeights
)
{
if (cellCentres.size() != globalCellCells.size())
{
FatalErrorIn
(
"scotchDecomp::decompose"
"(const labelListList&, const pointField&, const scalarField&)"
) << "Inconsistent number of cells (" << globalCellCells.size()
<< ") and number of cell centres (" << cellCentres.size()
<< ")." << exit(FatalError);
}
// Make Metis CSR (Compressed Storage Format) storage
// adjncy : contains neighbours (= edges in graph)
// xadj(celli) : start of information in adjncy for celli
List<int> adjncy;
List<int> xadj;
calcCSR(globalCellCells, adjncy, xadj);
// Decompose using weights
List<int> finalDecomp;
decompose(adjncy, xadj, cWeights, finalDecomp);
// Copy back to labelList
labelList decomp(finalDecomp.size());
forAll(decomp, i)
{
decomp[i] = finalDecomp[i];
}
return decomp;
}
void Foam::scotchDecomp::calcCSR
(
const polyMesh& mesh,
List<int>& adjncy,
List<int>& xadj
)
{
// Make Metis CSR (Compressed Storage Format) storage
// adjncy : contains neighbours (= edges in graph)
// xadj(celli) : start of information in adjncy for celli
xadj.setSize(mesh.nCells()+1);
// Initialise the number of internal faces of the cells to twice the
// number of internal faces
label nInternalFaces = 2*mesh.nInternalFaces();
// Check the boundary for coupled patches and add to the number of
// internal faces
const polyBoundaryMesh& pbm = mesh.boundaryMesh();
forAll(pbm, patchi)
{
if (isA<cyclicPolyPatch>(pbm[patchi]))
{
nInternalFaces += pbm[patchi].size();
}
}
// Create the adjncy array the size of the total number of internal and
// coupled faces
adjncy.setSize(nInternalFaces);
// Fill in xadj
// ~~~~~~~~~~~~
label freeAdj = 0;
for (label cellI = 0; cellI < mesh.nCells(); cellI++)
{
xadj[cellI] = freeAdj;
const labelList& cFaces = mesh.cells()[cellI];
forAll(cFaces, i)
{
label faceI = cFaces[i];
if
(
mesh.isInternalFace(faceI)
|| isA<cyclicPolyPatch>(pbm[pbm.whichPatch(faceI)])
)
{
freeAdj++;
}
}
}
xadj[mesh.nCells()] = freeAdj;
// Fill in adjncy
// ~~~~~~~~~~~~~~
labelList nFacesPerCell(mesh.nCells(), 0);
// Internal faces
for (label faceI = 0; faceI < mesh.nInternalFaces(); faceI++)
{
label own = mesh.faceOwner()[faceI];
label nei = mesh.faceNeighbour()[faceI];
adjncy[xadj[own] + nFacesPerCell[own]++] = nei;
adjncy[xadj[nei] + nFacesPerCell[nei]++] = own;
}
// Coupled faces. Only cyclics done.
forAll(pbm, patchi)
{
if (isA<cyclicPolyPatch>(pbm[patchi]))
{
const unallocLabelList& faceCells = pbm[patchi].faceCells();
label sizeby2 = faceCells.size()/2;
for (label facei=0; facei<sizeby2; facei++)
{
label own = faceCells[facei];
label nei = faceCells[facei + sizeby2];
adjncy[xadj[own] + nFacesPerCell[own]++] = nei;
adjncy[xadj[nei] + nFacesPerCell[nei]++] = own;
}
}
}
}
// From cell-cell connections to Metis format (like CompactListList)
void Foam::scotchDecomp::calcCSR
(
const labelListList& cellCells,
List<int>& adjncy,
List<int>& xadj
)
{
// Count number of internal faces
label nConnections = 0;
forAll(cellCells, coarseI)
{
nConnections += cellCells[coarseI].size();
}
// Create the adjncy array as twice the size of the total number of
// internal faces
adjncy.setSize(nConnections);
xadj.setSize(cellCells.size()+1);
// Fill in xadj
// ~~~~~~~~~~~~
label freeAdj = 0;
forAll(cellCells, coarseI)
{
xadj[coarseI] = freeAdj;
const labelList& cCells = cellCells[coarseI];
forAll(cCells, i)
{
adjncy[freeAdj++] = cCells[i];
}
}
xadj[cellCells.size()] = freeAdj;
}
// ************************************************************************* //