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Nektar::LibUtilities::MeshPartitionScotch Class Reference

#include <MeshPartitionScotch.h>

Inheritance diagram for Nektar::LibUtilities::MeshPartitionScotch:
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Public Member Functions

 MeshPartitionScotch (const SessionReaderSharedPtr &pSession)
 
virtual ~MeshPartitionScotch ()
 
- Public Member Functions inherited from Nektar::LibUtilities::MeshPartition
 MeshPartition (const SessionReaderSharedPtr &pSession)
 
virtual ~MeshPartition ()
 
void PartitionMesh (int nParts, bool shared=false, bool overlapping=false)
 
void WriteLocalPartition (SessionReaderSharedPtr &pSession)
 
void WriteAllPartitions (SessionReaderSharedPtr &pSession)
 
void PrintPartInfo (std::ostream &out)
 
void GetCompositeOrdering (CompositeOrdering &composites)
 
void GetBndRegionOrdering (BndRegionOrdering &composites)
 
void GetElementIDs (const int procid, std::vector< unsigned int > &tmp)
 

Static Public Member Functions

static MeshPartitionSharedPtr create (const SessionReaderSharedPtr &pSession)
 Creates an instance of this class. More...
 

Static Public Attributes

static std::string className
 Name of class. More...
 
static std::string cmdSwitch = SessionReader::RegisterCmdLineFlag("use-scotch","","Use Scotch for mesh partitioning.")
 

Private Member Functions

virtual void PartitionGraphImpl (int &nVerts, int &nVertConds, Nektar::Array< Nektar::OneD, int > &xadj, Nektar::Array< Nektar::OneD, int > &adjcy, Nektar::Array< Nektar::OneD, int > &vertWgt, Nektar::Array< Nektar::OneD, int > &vertSize, int &nparts, int &volume, Nektar::Array< Nektar::OneD, int > &part)
 
void PartGraphVKway (const SCOTCH_Num *const n, const SCOTCH_Num *const xadj, const SCOTCH_Num *const adjncy, const SCOTCH_Num *const vwgt, const SCOTCH_Num *const vsize, const SCOTCH_Num *const wgtflag, const SCOTCH_Num *const numflag, const SCOTCH_Num *const nparts, const SCOTCH_Num *const options, SCOTCH_Num *const volume, SCOTCH_Num *const part)
 
int PartGraph2 (const SCOTCH_Num *const n, const SCOTCH_Num *const xadj, const SCOTCH_Num *const adjncy, const SCOTCH_Num *const vwgt, const SCOTCH_Num *const adjwgt, const SCOTCH_Num *const numflag, const SCOTCH_Num *const nparts, SCOTCH_Num *const part, SCOTCH_Num flagval, double kbalval)
 

Detailed Description

Definition at line 49 of file MeshPartitionScotch.h.

Constructor & Destructor Documentation

Nektar::LibUtilities::MeshPartitionScotch::MeshPartitionScotch ( const SessionReaderSharedPtr pSession)

Definition at line 55 of file MeshPartitionScotch.cpp.

56  : MeshPartition(pSession)
57  {
58 
59  }
MeshPartition(const SessionReaderSharedPtr &pSession)
Nektar::LibUtilities::MeshPartitionScotch::~MeshPartitionScotch ( )
virtual

Definition at line 61 of file MeshPartitionScotch.cpp.

62  {
63 
64  }

Member Function Documentation

static MeshPartitionSharedPtr Nektar::LibUtilities::MeshPartitionScotch::create ( const SessionReaderSharedPtr pSession)
inlinestatic

Creates an instance of this class.

Definition at line 53 of file MeshPartitionScotch.h.

References Nektar::MemoryManager< DataType >::AllocateSharedPtr().

55  {
57  ::AllocateSharedPtr(pSession);
58  }
static boost::shared_ptr< DataType > AllocateSharedPtr()
Allocate a shared pointer from the memory pool.
int Nektar::LibUtilities::MeshPartitionScotch::PartGraph2 ( const SCOTCH_Num *const  n,
const SCOTCH_Num *const  xadj,
const SCOTCH_Num *const  adjncy,
const SCOTCH_Num *const  vwgt,
const SCOTCH_Num *const  adjwgt,
const SCOTCH_Num *const  numflag,
const SCOTCH_Num *const  nparts,
SCOTCH_Num *const  part,
SCOTCH_Num  flagval,
double  kbalval 
)
private

Definition at line 227 of file MeshPartitionScotch.cpp.

Referenced by PartGraphVKway().

238  {
239  // Scotch graph object to interface with libScotch
240  SCOTCH_Graph grafdat;
241  SCOTCH_Strat stradat;
242  SCOTCH_Num baseval;
243  SCOTCH_Num vertnbr;
244  int o;
245 
246  SCOTCH_graphInit (&grafdat);
247 
248  baseval = *numflag;
249  vertnbr = *n;
250 
251  o = 1; // Assume something will go wrong
252  if (SCOTCH_graphBuild (&grafdat, baseval, vertnbr, xadj, xadj + 1,
253  vwgt, NULL, xadj[vertnbr] - baseval, adjncy,
254  adjwgt) == 0) {
255  SCOTCH_stratInit (&stradat);
256  SCOTCH_stratGraphMapBuild (&stradat, flagval, *nparts, kbalval);
257 #ifdef SCOTCH_DEBUG_ALL
258  // TRICK: next instruction called only if graph is consistent
259  if (SCOTCH_graphCheck (&grafdat) == 0)
260 #endif /* SCOTCH_DEBUG_ALL */
261  o = SCOTCH_graphPart (&grafdat, *nparts, &stradat, part);
262  SCOTCH_stratExit (&stradat);
263  }
264  SCOTCH_graphExit (&grafdat);
265 
266  if (o != 0)
267  return (1);
268 
269  if (baseval != 0) { // MeTiS part array is based, Scotch is not
270  SCOTCH_Num vertnum;
271 
272  for (vertnum = 0; vertnum < vertnbr; vertnum ++)
273  part[vertnum] += baseval;
274  }
275 
276  return (0);
277  }
void Nektar::LibUtilities::MeshPartitionScotch::PartGraphVKway ( const SCOTCH_Num *const  n,
const SCOTCH_Num *const  xadj,
const SCOTCH_Num *const  adjncy,
const SCOTCH_Num *const  vwgt,
const SCOTCH_Num *const  vsize,
const SCOTCH_Num *const  wgtflag,
const SCOTCH_Num *const  numflag,
const SCOTCH_Num *const  nparts,
const SCOTCH_Num *const  options,
SCOTCH_Num *const  volume,
SCOTCH_Num *const  part 
)
private

Communication volume of current vertex

Definition at line 101 of file MeshPartitionScotch.cpp.

References PartGraph2().

Referenced by PartitionGraphImpl().

113  {
114  SCOTCH_Num baseval;
115  const SCOTCH_Num * vwgt2;
116  const SCOTCH_Num * vsize2;
117  SCOTCH_Num vsizval; /// Communication volume of current vertex
118  SCOTCH_Num vertnbr;
119  SCOTCH_Num vertnum;
120  SCOTCH_Num edgenum;
121  const SCOTCH_Num * edgetax;
122  const SCOTCH_Num * parttax;
123  SCOTCH_Num * nghbtab;
124  SCOTCH_Num commvol;
125 
126  vsize2 = ((*wgtflag & 1) != 0) ? vsize : NULL;
127  vwgt2 = ((*wgtflag & 2) != 0) ? vwgt : NULL;
128  baseval = *numflag;
129  vertnbr = *n;
130  edgetax = adjncy - baseval;
131 
132  // If no communication load data provided
133  if (vsize2 == NULL) {
134  if (PartGraph2 (n, xadj, adjncy, vwgt2, NULL, numflag, nparts,
135  part, SCOTCH_STRATDEFAULT, 0.01) != 0)
136  return;
137  }
138 
139  // Will have to turn communication volumes into edge loads
140  else {
141  const SCOTCH_Num * vsiztax;
142  SCOTCH_Num edgenbr;
143  SCOTCH_Num * edlotax;
144  int o;
145 
146  edgenbr = xadj[vertnbr] - baseval;
147  if ((edlotax =
148  (SCOTCH_Num*) malloc (edgenbr * sizeof (SCOTCH_Num))) == NULL)
149  {
150  return;
151  }
152 
153  edlotax -= baseval; // Base access to edlotax
154  vsiztax = vsize2 - baseval;
155 
156  // Un-based scan of vertex array xadj
157  for (vertnum = 0, edgenum = baseval;
158  vertnum < vertnbr; vertnum ++) {
159  SCOTCH_Num vsizval; // Communication size of current vertex
160  SCOTCH_Num edgennd;
161 
162  vsizval = vsize2[vertnum];
163  // Based traversal of edge array adjncy
164  for (edgennd = xadj[vertnum + 1];
165  edgenum < edgennd;
166  edgenum ++) {
167 
168  SCOTCH_Num vertend; // Based end vertex number
169 
170  vertend = edgetax[edgenum];
171  edlotax[edgenum] = vsizval + vsiztax[vertend];
172  }
173  }
174 
175  o = PartGraph2 (n, xadj, adjncy, vwgt2, edlotax + baseval, numflag,
176  nparts, part, SCOTCH_STRATDEFAULT, 0.01);
177 
178  free (edlotax + baseval);
179 
180  if (o != 0)
181  return;
182  }
183 
184  if ((nghbtab =
185  (SCOTCH_Num*) malloc (*nparts * sizeof (SCOTCH_Num))) == NULL)
186  {
187  return;
188  }
189 
190  memset (nghbtab, ~0, *nparts * sizeof (SCOTCH_Num));
191 
192  parttax = part - baseval;
193  vsizval = 1; // Assume no vertex communication sizes
194 
195  // Un-based scan of vertex array xadj
196  for (vertnum = 0, edgenum = baseval, commvol = 0;
197  vertnum < vertnbr; vertnum ++) {
198  SCOTCH_Num partval;
199  SCOTCH_Num edgennd;
200 
201  partval = part[vertnum];
202  nghbtab[partval] = vertnum; // Do not count local neighbors in
203  // communication volume
204  if (vsize2 != NULL)
205  vsizval = vsize2[vertnum];
206 
207  // Based traversal of edge array adjncy
208  for (edgennd = xadj[vertnum + 1]; edgenum < edgennd; edgenum ++) {
209  SCOTCH_Num vertend; // Based end vertex number
210  SCOTCH_Num partend;
211 
212  vertend = edgetax[edgenum];
213  partend = parttax[vertend];
214 
215  // If first neighbor in this part set part as accounted for
216  if (nghbtab[partend] != vertnum) {
217  nghbtab[partend] = vertnum;
218  commvol += vsizval;
219  }
220  }
221  }
222  *volume = commvol;
223 
224  free (nghbtab);
225  }
int PartGraph2(const SCOTCH_Num *const n, const SCOTCH_Num *const xadj, const SCOTCH_Num *const adjncy, const SCOTCH_Num *const vwgt, const SCOTCH_Num *const adjwgt, const SCOTCH_Num *const numflag, const SCOTCH_Num *const nparts, SCOTCH_Num *const part, SCOTCH_Num flagval, double kbalval)
void Nektar::LibUtilities::MeshPartitionScotch::PartitionGraphImpl ( int &  nVerts,
int &  nVertConds,
Nektar::Array< Nektar::OneD, int > &  xadj,
Nektar::Array< Nektar::OneD, int > &  adjcy,
Nektar::Array< Nektar::OneD, int > &  vertWgt,
Nektar::Array< Nektar::OneD, int > &  vertSize,
int &  nparts,
int &  volume,
Nektar::Array< Nektar::OneD, int > &  part 
)
privatevirtual

Implements Nektar::LibUtilities::MeshPartition.

Definition at line 66 of file MeshPartitionScotch.cpp.

References PartGraphVKway().

76  {
77  int wgtflag = 0;
78  int *vwgt = 0;
79  int *vsize = 0;
80  if (vertWgt.num_elements() > 0)
81  {
82  wgtflag += 1;
83  vwgt = &vertWgt[0];
84  }
85  if (vertSize.num_elements() > 0)
86  {
87  wgtflag += 2;
88  vsize = &vertSize[0];
89  }
90  int numflag = 0;
91  // number of balancing conditions (size of vertex multi-weight)
92  int options[5];
93  options[0] = 0;
94 
95  PartGraphVKway(&nVerts, &xadj[0], &adjcy[0], vwgt, vsize,
96  &wgtflag, &numflag, &nparts, options, &volume,
97  &part[0]);
98  }
void PartGraphVKway(const SCOTCH_Num *const n, const SCOTCH_Num *const xadj, const SCOTCH_Num *const adjncy, const SCOTCH_Num *const vwgt, const SCOTCH_Num *const vsize, const SCOTCH_Num *const wgtflag, const SCOTCH_Num *const numflag, const SCOTCH_Num *const nparts, const SCOTCH_Num *const options, SCOTCH_Num *const volume, SCOTCH_Num *const part)

Member Data Documentation

std::string Nektar::LibUtilities::MeshPartitionScotch::className
static
Initial value:
"Scotch",
"Partitioning using the Scotch library.")

Name of class.

Definition at line 61 of file MeshPartitionScotch.h.

std::string Nektar::LibUtilities::MeshPartitionScotch::cmdSwitch = SessionReader::RegisterCmdLineFlag("use-scotch","","Use Scotch for mesh partitioning.")
static

Definition at line 62 of file MeshPartitionScotch.h.