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Ifpack_ICT.cpp
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42 
43 #include "Ifpack_ConfigDefs.h"
44 #include "Ifpack_Preconditioner.h"
45 #include "Ifpack_ICT.h"
46 #include "Ifpack_Condest.h"
47 #include "Ifpack_Utils.h"
48 #include "Ifpack_HashTable.h"
49 #include "Epetra_SerialComm.h"
50 #include "Epetra_Comm.h"
51 #include "Epetra_Map.h"
52 #include "Epetra_RowMatrix.h"
53 #include "Epetra_CrsMatrix.h"
54 #include "Epetra_Vector.h"
55 #include "Epetra_MultiVector.h"
56 #include "Epetra_Util.h"
57 #include "Teuchos_ParameterList.hpp"
58 #include "Teuchos_RefCountPtr.hpp"
59 #include <functional>
60 
61 //==============================================================================
62 // FIXME: allocate Comm_ and Time_ the first Initialize() call
64  A_(*A),
65  Comm_(A_.Comm()),
66  Condest_(-1.0),
67  Athresh_(0.0),
68  Rthresh_(1.0),
69  LevelOfFill_(1.0),
70  DropTolerance_(0.0),
71  Relax_(0.0),
72  IsInitialized_(false),
73  IsComputed_(false),
74  UseTranspose_(false),
75  NumMyRows_(0),
76  NumInitialize_(0),
77  NumCompute_(0),
78  NumApplyInverse_(0),
79  InitializeTime_(0.0),
80  ComputeTime_(0.0),
81  ApplyInverseTime_(0.0),
82  ComputeFlops_(0.0),
83  ApplyInverseFlops_(0.0),
84  Time_(Comm()),
85  GlobalNonzeros_(0)
86 {
87  // do nothing here
88 }
89 
90 //==============================================================================
92 {
93  Destroy();
94 }
95 
96 //==============================================================================
98 {
99  IsInitialized_ = false;
100  IsComputed_ = false;
101 }
102 
103 //==========================================================================
105 {
106  using std::cerr;
107  using std::endl;
108 
109  try
110  {
111  LevelOfFill_ = List.get("fact: ict level-of-fill",LevelOfFill_);
112  Athresh_ = List.get("fact: absolute threshold", Athresh_);
113  Rthresh_ = List.get("fact: relative threshold", Rthresh_);
114  Relax_ = List.get("fact: relax value", Relax_);
115  DropTolerance_ = List.get("fact: drop tolerance", DropTolerance_);
116 
117  // set label
118  Label_ = "ICT (fill=" + Ifpack_toString(LevelOfFill())
119  + ", athr=" + Ifpack_toString(AbsoluteThreshold())
120  + ", rthr=" + Ifpack_toString(RelativeThreshold())
121  + ", relax=" + Ifpack_toString(RelaxValue())
122  + ", droptol=" + Ifpack_toString(DropTolerance())
123  + ")";
124 
125  return(0);
126  }
127  catch (...)
128  {
129  cerr << "Caught an exception while parsing the parameter list" << endl;
130  cerr << "This typically means that a parameter was set with the" << endl;
131  cerr << "wrong type (for example, int instead of double). " << endl;
132  cerr << "please check the documentation for the type required by each parameter." << endl;
133  IFPACK_CHK_ERR(-1);
134  }
135 }
136 
137 //==========================================================================
139 {
140  // clean data if present
141  Destroy();
142 
144 
145  // matrix must be square. Check only on one processor
146  if (Comm().NumProc() == 1 && Matrix().NumMyRows() != Matrix().NumMyCols())
147  IFPACK_CHK_ERR(-2);
148 
150 
151  // nothing else to do here
152  IsInitialized_ = true;
153  ++NumInitialize_;
155 
156  return(0);
157 }
158 
159 //==========================================================================
160 template<typename int_type>
162 {
163  if (!IsInitialized())
165 
167  IsComputed_ = false;
168 
169  NumMyRows_ = A_.NumMyRows();
170  int Length = A_.MaxNumEntries();
171  std::vector<int> RowIndices(Length);
172  std::vector<double> RowValues(Length);
173 
174  bool distributed = (Comm().NumProc() > 1)?true:false;
175 
176 #if !defined(EPETRA_NO_32BIT_GLOBAL_INDICES) || !defined(EPETRA_NO_64BIT_GLOBAL_INDICES)
177  if (distributed)
178  {
180 #if !defined(EPETRA_NO_32BIT_GLOBAL_INDICES)
183  else
184 #endif
185 #if !defined(EPETRA_NO_64BIT_GLOBAL_INDICES)
187  SerialMap_ = Teuchos::rcp(new Epetra_Map((long long) NumMyRows_, (long long) 0, *SerialComm_));
188  else
189 #endif
190  throw "Ifpack_ICT::TCompute: Global indices unknown.";
191  assert (SerialComm_.get() != 0);
192  assert (SerialMap_.get() != 0);
193  }
194  else
195  SerialMap_ = Teuchos::rcp(const_cast<Epetra_Map*>(&A_.RowMatrixRowMap()), false);
196 #endif
197 
198  int RowNnz;
199 #ifdef IFPACK_FLOPCOUNTERS
200  double flops = 0.0;
201 #endif
202 
204  if (H_.get() == 0)
205  IFPACK_CHK_ERR(-5); // memory allocation error
206 
207  // get A(0,0) element and insert it (after sqrt)
208  IFPACK_CHK_ERR(A_.ExtractMyRowCopy(0,Length,RowNnz,
209  &RowValues[0],&RowIndices[0]));
210 
211  // skip off-processor elements
212  if (distributed)
213  {
214  int count = 0;
215  for (int i = 0 ;i < RowNnz ; ++i)
216  {
217  if (RowIndices[i] < NumMyRows_){
218  RowIndices[count] = RowIndices[i];
219  RowValues[count] = RowValues[i];
220  ++count;
221  }
222  else
223  continue;
224  }
225  RowNnz = count;
226  }
227 
228  // modify diagonal
229  double diag_val = 0.0;
230  for (int i = 0 ;i < RowNnz ; ++i) {
231  if (RowIndices[i] == 0) {
232  double& v = RowValues[i];
233  diag_val = AbsoluteThreshold() * EPETRA_SGN(v) +
234  RelativeThreshold() * v;
235  break;
236  }
237  }
238 
239  diag_val = sqrt(diag_val);
240  int_type diag_idx = 0;
241  EPETRA_CHK_ERR(H_->InsertGlobalValues(0,1,&diag_val, &diag_idx));
242 
243  // The 10 is just a small constant to limit collisons as the actual keys
244  // we store are the indices and not integers
245  // [0..A_.MaxNumEntries()*LevelofFill()].
247 
248  // start factorization for line 1
249  for (int row_i = 1 ; row_i < NumMyRows_ ; ++row_i) {
250 
251  // get row `row_i' of the matrix
252  IFPACK_CHK_ERR(A_.ExtractMyRowCopy(row_i,Length,RowNnz,
253  &RowValues[0],&RowIndices[0]));
254 
255  // skip off-processor elements
256  if (distributed)
257  {
258  int count = 0;
259  for (int i = 0 ;i < RowNnz ; ++i)
260  {
261  if (RowIndices[i] < NumMyRows_){
262  RowIndices[count] = RowIndices[i];
263  RowValues[count] = RowValues[i];
264  ++count;
265  }
266  else
267  continue;
268  }
269  RowNnz = count;
270  }
271 
272  // number of nonzeros in this row are defined as the nonzeros
273  // of the matrix, plus the level of fill
274  int LOF = (int)(LevelOfFill() * RowNnz);
275  if (LOF == 0) LOF = 1;
276 
277  // convert line `row_i' into hash for fast access
278  Hash.reset();
279 
280  double h_ii = 0.0;
281  for (int i = 0 ; i < RowNnz ; ++i) {
282  if (RowIndices[i] == row_i) {
283  double& v = RowValues[i];
284  h_ii = AbsoluteThreshold() * EPETRA_SGN(v) + RelativeThreshold() * v;
285  }
286  else if (RowIndices[i] < row_i)
287  {
288  Hash.set(RowIndices[i], RowValues[i], true);
289  }
290  }
291 
292  // form element (row_i, col_j)
293  // I start from the first row that has a nonzero column
294  // index in row_i.
295  for (int col_j = RowIndices[0] ; col_j < row_i ; ++col_j) {
296 
297  double h_ij = 0.0, h_jj = 0.0;
298  // note: get() returns 0.0 if col_j is not found
299  h_ij = Hash.get(col_j);
300 
301  // get pointers to row `col_j'
302  int_type* ColIndices;
303  double* ColValues;
304  int ColNnz;
305  int_type col_j_GID = (int_type) H_->RowMap().GID64(col_j);
306  H_->ExtractGlobalRowView(col_j_GID, ColNnz, ColValues, ColIndices);
307 
308  for (int k = 0 ; k < ColNnz ; ++k) {
309  int_type col_k = ColIndices[k];
310 
311  if (col_k == col_j)
312  h_jj = ColValues[k];
313  else {
314  double xxx = Hash.get(col_k);
315  if (xxx != 0.0)
316  {
317  h_ij -= ColValues[k] * xxx;
318 #ifdef IFPACK_FLOPCOUNTERS
319  flops += 2.0;
320 #endif
321  }
322  }
323  }
324 
325  h_ij /= h_jj;
326 
327  if (IFPACK_ABS(h_ij) > DropTolerance_)
328  {
329  Hash.set(col_j, h_ij);
330  }
331 
332 #ifdef IFPACK_FLOPCOUNTERS
333  // only approx
334  ComputeFlops_ += 2.0 * flops + 1.0;
335 #endif
336  }
337 
338  int size = Hash.getNumEntries();
339 
340  std::vector<double> AbsRow(size);
341  int count = 0;
342 
343  // +1 because I use the extra position for diagonal in insert
344  std::vector<int_type> keys(size + 1);
345  std::vector<double> values(size + 1);
346 
347  Hash.arrayify(&keys[0], &values[0]);
348 
349  for (int i = 0 ; i < size ; ++i)
350  {
351  AbsRow[i] = IFPACK_ABS(values[i]);
352  }
353  count = size;
354 
355  double cutoff = 0.0;
356  if (count > LOF) {
357  nth_element(AbsRow.begin(), AbsRow.begin() + LOF, AbsRow.begin() + count,
358 
359  std::greater<double>());
360  cutoff = AbsRow[LOF];
361  }
362 
363  for (int i = 0 ; i < size ; ++i)
364  {
365  h_ii -= values[i] * values[i];
366  }
367 
368  if (h_ii < 0.0) h_ii = 1e-12;;
369 
370  h_ii = sqrt(h_ii);
371 
372 #ifdef IFPACK_FLOPCOUNTERS
373  // only approx, + 1 == sqrt
374  ComputeFlops_ += 2 * size + 1;
375 #endif
376 
377  double DiscardedElements = 0.0;
378 
379  count = 0;
380  for (int i = 0 ; i < size ; ++i)
381  {
382  if (IFPACK_ABS(values[i]) > cutoff)
383  {
384  values[count] = values[i];
385  keys[count] = keys[i];
386  ++count;
387  }
388  else
389  DiscardedElements += values[i];
390  }
391 
392  if (RelaxValue() != 0.0) {
393  DiscardedElements *= RelaxValue();
394  h_ii += DiscardedElements;
395  }
396 
397  values[count] = h_ii;
398  keys[count] = (int_type) H_->RowMap().GID64(row_i);
399  ++count;
400 
401  H_->InsertGlobalValues((int_type) H_->RowMap().GID64(row_i), count, &(values[0]), (int_type*)&(keys[0]));
402  }
403 
404  IFPACK_CHK_ERR(H_->FillComplete());
405 
406 #if 0
407  // to check the complete factorization
408  Epetra_Vector LHS(Matrix().RowMatrixRowMap());
409  Epetra_Vector RHS1(Matrix().RowMatrixRowMap());
410  Epetra_Vector RHS2(Matrix().RowMatrixRowMap());
411  Epetra_Vector RHS3(Matrix().RowMatrixRowMap());
412  LHS.Random();
413 
414  Matrix().Multiply(false,LHS,RHS1);
415  H_->Multiply(true,LHS,RHS2);
416  H_->Multiply(false,RHS2,RHS3);
417 
418  RHS1.Update(-1.0, RHS3, 1.0);
419  std::cout << endl;
420  std::cout << RHS1;
421 #endif
422  long long MyNonzeros = H_->NumGlobalNonzeros64();
423  Comm().SumAll(&MyNonzeros, &GlobalNonzeros_, 1);
424 
425  IsComputed_ = true;
426 #ifdef IFPACK_FLOPCOUNTERS
427  double TotalFlops; // sum across all the processors
428  A_.Comm().SumAll(&flops, &TotalFlops, 1);
429  ComputeFlops_ += TotalFlops;
430 #endif
431  ++NumCompute_;
433 
434  return(0);
435 
436 }
437 
439 #ifndef EPETRA_NO_32BIT_GLOBAL_INDICES
441  return TCompute<int>();
442  }
443  else
444 #endif
445 #ifndef EPETRA_NO_64BIT_GLOBAL_INDICES
447  return TCompute<long long>();
448  }
449  else
450 #endif
451  throw "Ifpack_ICT::Compute: GlobalIndices type unknown for A_";
452 }
453 
454 //=============================================================================
456  Epetra_MultiVector& Y) const
457 {
458 
459  if (!IsComputed())
460  IFPACK_CHK_ERR(-3); // compute preconditioner first
461 
462  if (X.NumVectors() != Y.NumVectors())
463  IFPACK_CHK_ERR(-2); // Return error: X and Y not the same size
464 
466 
467  // AztecOO gives X and Y pointing to the same memory location,
468  // need to create an auxiliary vector, Xcopy
469  Teuchos::RefCountPtr<const Epetra_MultiVector> Xcopy;
470  if (X.Pointers()[0] == Y.Pointers()[0])
471  Xcopy = Teuchos::rcp( new Epetra_MultiVector(X) );
472  else
473  Xcopy = Teuchos::rcp( &X, false );
474 
475  // NOTE: H_ is based on SerialMap_, while Xcopy is based
476  // on A.Map()... which are in general different. However, Solve()
477  // does not seem to care... which is fine with me.
478  //
479  EPETRA_CHK_ERR(H_->Solve(false,false,false,*Xcopy,Y));
480  EPETRA_CHK_ERR(H_->Solve(false,true,false,Y,Y));
481 
482 #ifdef IFPACK_FLOPCOUNTERS
483  // these are global flop count
485 #endif
486 
489 
490  return(0);
491 }
492 //=============================================================================
493 // This function finds X such that LDU Y = X or U(trans) D L(trans) Y = X for multiple RHS
495  Epetra_MultiVector& /* Y */) const
496 {
497 
498  IFPACK_CHK_ERR(-98);
499 }
500 
501 //=============================================================================
503  const int MaxIters, const double Tol,
504  Epetra_RowMatrix* Matrix_in)
505 {
506  if (!IsComputed()) // cannot compute right now
507  return(-1.0);
508 
509  // NOTE: this is computing the *local* condest
510  if (Condest_ == -1.0)
511  Condest_ = Ifpack_Condest(*this, CT, MaxIters, Tol, Matrix_in);
512 
513  return(Condest_);
514 }
515 
516 //=============================================================================
517 std::ostream&
518 Ifpack_ICT::Print(std::ostream& os) const
519 {
520  using std::endl;
521 
522  if (!Comm().MyPID()) {
523  os << endl;
524  os << "================================================================================" << endl;
525  os << "Ifpack_ICT: " << Label() << endl << endl;
526  os << "Level-of-fill = " << LevelOfFill() << endl;
527  os << "Absolute threshold = " << AbsoluteThreshold() << endl;
528  os << "Relative threshold = " << RelativeThreshold() << endl;
529  os << "Relax value = " << RelaxValue() << endl;
530  os << "Condition number estimate = " << Condest() << endl;
531  os << "Global number of rows = " << Matrix().NumGlobalRows64() << endl;
532  if (IsComputed_) {
533  os << "Number of nonzeros of H = " << H_->NumGlobalNonzeros64() << endl;
534  os << "nonzeros / rows = "
535  << 1.0 * H_->NumGlobalNonzeros64() / H_->NumGlobalRows64() << endl;
536  }
537  os << endl;
538  os << "Phase # calls Total Time (s) Total MFlops MFlops/s" << endl;
539  os << "----- ------- -------------- ------------ --------" << endl;
540  os << "Initialize() " << std::setw(5) << NumInitialize()
541  << " " << std::setw(15) << InitializeTime()
542  << " 0.0 0.0" << endl;
543  os << "Compute() " << std::setw(5) << NumCompute()
544  << " " << std::setw(15) << ComputeTime()
545  << " " << std::setw(15) << 1.0e-6 * ComputeFlops();
546  if (ComputeTime() != 0.0)
547  os << " " << std::setw(15) << 1.0e-6 * ComputeFlops() / ComputeTime() << endl;
548  else
549  os << " " << std::setw(15) << 0.0 << endl;
550  os << "ApplyInverse() " << std::setw(5) << NumApplyInverse()
551  << " " << std::setw(15) << ApplyInverseTime()
552  << " " << std::setw(15) << 1.0e-6 * ApplyInverseFlops();
553  if (ApplyInverseTime() != 0.0)
554  os << " " << std::setw(15) << 1.0e-6 * ApplyInverseFlops() / ApplyInverseTime() << endl;
555  else
556  os << " " << std::setw(15) << 0.0 << endl;
557  os << "================================================================================" << endl;
558  os << endl;
559  }
560 
561 
562  return(os);
563 }
double RelaxValue() const
Returns the relaxation value.
Definition: Ifpack_ICT.h:317
int NumApplyInverse_
Contains the number of successful call to ApplyInverse().
Definition: Ifpack_ICT.h:379
int NumCompute_
Contains the number of successful call to Compute().
Definition: Ifpack_ICT.h:377
virtual const Epetra_Map & RowMatrixRowMap() const =0
virtual std::ostream & Print(std::ostream &os) const
Prints basic information on iostream. This function is used by operator&lt;&lt;.
Definition: Ifpack_ICT.cpp:518
double LevelOfFill() const
Returns the level-of-fill.
Definition: Ifpack_ICT.h:299
bool GlobalIndicesLongLong() const
double ComputeTime_
Contains the time for all successful calls to Compute().
Definition: Ifpack_ICT.h:383
const Epetra_Comm & Comm() const
Returns the Epetra_BlockMap object associated with the range of this matrix operator.
Definition: Ifpack_ICT.h:224
T & get(ParameterList &l, const std::string &name)
double ElapsedTime(void) const
double LevelOfFill_
Level of fill.
Definition: Ifpack_ICT.h:359
Epetra_Time Time_
Used for timing purposes.
Definition: Ifpack_ICT.h:391
double ApplyInverseTime_
Contains the time for all successful calls to ApplyInverse().
Definition: Ifpack_ICT.h:385
#define EPETRA_CHK_ERR(a)
int SetParameters(Teuchos::ParameterList &parameterlis)
Set parameters using a Teuchos::ParameterList object.
Definition: Ifpack_ICT.cpp:104
bool IsInitialized() const
Returns true is the preconditioner has been successfully initialized.
Definition: Ifpack_ICT.h:116
int ApplyInverse(const Epetra_MultiVector &X, Epetra_MultiVector &Y) const
Returns the result of a Ifpack_ICT forward/back solve on a Epetra_MultiVector X in Y...
Definition: Ifpack_ICT.cpp:455
double ComputeFlops_
Contains the number of flops for Compute().
Definition: Ifpack_ICT.h:387
bool GlobalIndicesInt() const
Teuchos::RefCountPtr< Epetra_CrsMatrix > H_
Contains the Cholesky factorization.
Definition: Ifpack_ICT.h:351
double ApplyInverseFlops_
Contain sthe number of flops for ApplyInverse().
Definition: Ifpack_ICT.h:389
int Initialize()
Initialize L and U with values from user matrix A.
Definition: Ifpack_ICT.cpp:138
double DropTolerance_
During factorization, drop all values below this.
Definition: Ifpack_ICT.h:361
Teuchos::RefCountPtr< Epetra_Map > SerialMap_
Definition: Ifpack_ICT.h:395
bool IsInitialized_
If true, the preconditioner has been successfully initialized.
Definition: Ifpack_ICT.h:367
int Apply(const Epetra_MultiVector &X, Epetra_MultiVector &Y) const
Definition: Ifpack_ICT.cpp:494
Ifpack_CondestType
Ifpack_CondestType: enum to define the type of condition number estimate.
virtual int SumAll(double *PartialSums, double *GlobalSums, int Count) const =0
virtual int MaxNumEntries() const =0
long long GlobalNonzeros_
Global number of nonzeros in L and U factors.
Definition: Ifpack_ICT.h:393
virtual const Epetra_Comm & Comm() const =0
std::string Label_
Label of this object.
Definition: Ifpack_ICT.h:365
TEUCHOS_DEPRECATED RCP< T > rcp(T *p, Dealloc_T dealloc, bool owns_mem)
double DropTolerance() const
Returns the drop threshold.
Definition: Ifpack_ICT.h:323
Ifpack_ICT(const Epetra_RowMatrix *A)
Ifpack_ICT constuctor with variable number of indices per row.
Definition: Ifpack_ICT.cpp:63
virtual int NumInitialize() const
Returns the number of calls to Initialize().
Definition: Ifpack_ICT.h:242
double Rthresh_
Relative threshold.
Definition: Ifpack_ICT.h:357
double InitializeTime_
Contains the time for all successful calls to Initialize().
Definition: Ifpack_ICT.h:381
#define EPETRA_SGN(x)
virtual int NumCompute() const
Returns the number of calls to Compute().
Definition: Ifpack_ICT.h:248
const char * Label() const
Definition: Ifpack_ICT.h:227
virtual int NumMyRows() const =0
int NumInitialize_
Contains the number of successful calls to Initialize().
Definition: Ifpack_ICT.h:375
double Condest() const
Returns the computed condition number estimate, or -1.0 if not computed.
Definition: Ifpack_ICT.h:175
int TCompute()
Definition: Ifpack_ICT.cpp:161
std::string Ifpack_toString(const int &x)
Converts an integer to std::string.
virtual double ComputeTime() const
Returns the time spent in Compute().
Definition: Ifpack_ICT.h:266
#define false
void Destroy()
Destroys all data associated to the preconditioner.
Definition: Ifpack_ICT.cpp:97
double Relax_
Relaxation value.
Definition: Ifpack_ICT.h:363
virtual double ApplyInverseTime() const
Returns the time spent in ApplyInverse().
Definition: Ifpack_ICT.h:272
virtual int Multiply(bool TransA, const Epetra_MultiVector &X, Epetra_MultiVector &Y) const =0
double Ifpack_Condest(const Ifpack_Preconditioner &IFP, const Ifpack_CondestType CT, const int MaxIters, const double Tol, Epetra_RowMatrix *Matrix)
virtual double ComputeFlops() const
Returns the number of flops in all applications of Compute().
Definition: Ifpack_ICT.h:284
bool IsComputed() const
If factor is completed, this query returns true, otherwise it returns false.
Definition: Ifpack_ICT.h:142
virtual int NumProc() const =0
#define IFPACK_ABS(x)
double RelativeThreshold() const
Returns the relative threshold.
Definition: Ifpack_ICT.h:311
Teuchos::RefCountPtr< Epetra_SerialComm > SerialComm_
Definition: Ifpack_ICT.h:394
virtual int ExtractMyRowCopy(int MyRow, int Length, int &NumEntries, double *Values, int *Indices) const =0
const Epetra_RowMatrix & Matrix() const
Returns a reference to the matrix to be preconditioned.
Definition: Ifpack_ICT.h:110
virtual double ApplyInverseFlops() const
Returns the number of flops in all applications of ApplyInverse().
Definition: Ifpack_ICT.h:290
double Condest_
Contains the estimate of the condition number, if -1.0 if not computed.
Definition: Ifpack_ICT.h:353
bool IsComputed_
If true, the preconditioner has been successfully computed.
Definition: Ifpack_ICT.h:369
virtual double InitializeTime() const
Returns the time spent in Initialize().
Definition: Ifpack_ICT.h:260
int Compute()
Compute IC factor U using the specified graph, diagonal perturbation thresholds and relaxation parame...
Definition: Ifpack_ICT.cpp:438
int NumMyRows_
Number of local rows in the matrix.
Definition: Ifpack_ICT.h:373
#define IFPACK_CHK_ERR(ifpack_err)
virtual int NumApplyInverse() const
Returns the number of calls to ApplyInverse().
Definition: Ifpack_ICT.h:254
const Epetra_RowMatrix & A_
Reference to the matrix to be preconditioned, supposed symmetric.
Definition: Ifpack_ICT.h:347
void ResetStartTime(void)
double AbsoluteThreshold() const
Returns the absolute threshold.
Definition: Ifpack_ICT.h:305
virtual ~Ifpack_ICT()
Ifpack_ICT Destructor.
Definition: Ifpack_ICT.cpp:91
virtual long long NumGlobalRows64() const =0
double Athresh_
Absolute threshold.
Definition: Ifpack_ICT.h:355