Fix rewrite for eliminating constant factors of PI from argument to sine (#8031)
[cvc5.git] / src / theory / arith / tableau.cpp
index d6a30ac91edde85f906916e322deec9197966e30..6f3ddd5eb99e34a38187780439e7dfc73988646f 100644 (file)
-/*********************                                                        */
-/*! \file tableau.cpp
- ** \verbatim
- ** Original author: taking
- ** Major contributors: none
- ** Minor contributors (to current version): none
- ** This file is part of the CVC4 prototype.
- ** Copyright (c) 2009, 2010  The Analysis of Computer Systems Group (ACSys)
- ** Courant Institute of Mathematical Sciences
- ** New York University
- ** See the file COPYING in the top-level source directory for licensing
- ** information.\endverbatim
- **
- ** \brief [[ Add one-line brief description here ]]
- **
- ** [[ Add lengthier description here ]]
- ** \todo document this file
- **/
+/******************************************************************************
+ * Top contributors (to current version):
+ *   Tim King
+ *
+ * This file is part of the cvc5 project.
+ *
+ * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
+ * in the top-level source directory and their institutional affiliations.
+ * All rights reserved.  See the file COPYING in the top-level source
+ * directory for licensing information.
+ * ****************************************************************************
+ *
+ * [[ Add one-line brief description here ]]
+ *
+ * [[ Add lengthier description here ]]
+ * \todo document this file
+ */
+
+#include "base/output.h"
+#include "theory/arith/tableau.h"
 
+using namespace std;
+namespace cvc5 {
+namespace theory {
+namespace arith {
 
-#include "theory/arith/tableau.h"
 
-using namespace CVC4;
-using namespace CVC4::theory;
-using namespace CVC4::theory::arith;
+void Tableau::pivot(ArithVar oldBasic, ArithVar newBasic, CoefficientChangeCallback& cb){
+  Assert(isBasic(oldBasic));
+  Assert(!isBasic(newBasic));
+  Assert(d_mergeBuffer.empty());
 
-Row::Row(ArithVar basic,
-         const std::vector< Rational >& coefficients,
-         const std::vector< ArithVar >& variables):
-  d_x_i(basic),
-  d_coeffs(){
+  Debug("tableau") << "Tableau::pivot(" <<  oldBasic <<", " << newBasic <<")"  << endl;
 
-  Assert(coefficients.size() == variables.size() );
+  RowIndex ridx = basicToRowIndex(oldBasic);
 
-  std::vector<Rational>::const_iterator coeffIter = coefficients.begin();
-  std::vector<Rational>::const_iterator coeffEnd = coefficients.end();
-  std::vector<ArithVar>::const_iterator varIter = variables.begin();
+  rowPivot(oldBasic, newBasic, cb);
+  Assert(ridx == basicToRowIndex(newBasic));
 
-  for(; coeffIter != coeffEnd; ++coeffIter, ++varIter){
-    const Rational& coeff = *coeffIter;
-    ArithVar var_i = *varIter;
+  loadRowIntoBuffer(ridx);
 
-    Assert(var_i != d_x_i);
-    Assert(!has(var_i));
-    Assert(coeff != Rational(0,1));
+  ColIterator colIter = colIterator(newBasic);
+  while(!colIter.atEnd()){
+    EntryID id = colIter.getID();
+    Entry& entry = d_entries.get(id);
 
-    d_coeffs[var_i] = coeff;
-    Assert(d_coeffs[var_i] != Rational(0,1));
-  }
-}
-void Row::substitute(Row& row_s){
-  ArithVar x_s = row_s.basicVar();
-
-  Assert(has(x_s));
-  Assert(x_s != d_x_i);
-
-  Rational zero(0,1);
-
-  Rational a_rs = lookup(x_s);
-  Assert(a_rs != zero);
-  d_coeffs.erase(x_s);
-
-  for(iterator iter = row_s.begin(), iter_end = row_s.end();
-      iter != iter_end; ++iter){
-    ArithVar x_j = iter->first;
-    Rational a_sj = iter->second;
-    a_sj *= a_rs;
-    CoefficientTable::iterator coeff_iter = d_coeffs.find(x_j);
-
-    if(coeff_iter != d_coeffs.end()){
-      coeff_iter->second += a_sj;
-      if(coeff_iter->second == zero){
-        d_coeffs.erase(coeff_iter);
-      }
+    ++colIter; //needs to be incremented before the variable is removed
+    if(entry.getRowIndex() == ridx){ continue; }
+
+    RowIndex to = entry.getRowIndex();
+    Rational coeff = entry.getCoefficient();
+    if(cb.canUseRow(to)){
+      rowPlusBufferTimesConstant(to, coeff, cb);
     }else{
-      d_coeffs.insert(std::make_pair(x_j,a_sj));
+      rowPlusBufferTimesConstant(to, coeff);
     }
   }
+  clearBuffer();
+
+  //Clear the column for used for this variable
+
+  Assert(d_mergeBuffer.empty());
+  Assert(!isBasic(oldBasic));
+  Assert(isBasic(newBasic));
+  Assert(getColLength(newBasic) == 1);
 }
 
-void Row::pivot(ArithVar x_j){
-  Rational negInverseA_rs = -(lookup(x_j).inverse());
-  d_coeffs[d_x_i] = Rational(Integer(-1));
-  d_coeffs.erase(x_j);
+/**
+ * Changes basic to newbasic (a variable on the row).
+ */
+void Tableau::rowPivot(ArithVar basicOld, ArithVar basicNew, CoefficientChangeCallback& cb){
+  Assert(isBasic(basicOld));
+  Assert(!isBasic(basicNew));
 
-  d_x_i = x_j;
+  RowIndex rid = basicToRowIndex(basicOld);
 
-  for(iterator nonbasicIter = begin(), nonbasicIter_end = end();
-      nonbasicIter != nonbasicIter_end; ++nonbasicIter){
-    nonbasicIter->second *= negInverseA_rs;
-  }
+  EntryID newBasicID = findOnRow(rid, basicNew);
 
-}
+  Assert(newBasicID != ENTRYID_SENTINEL);
+
+  Tableau::Entry& newBasicEntry = d_entries.get(newBasicID);
+  const Rational& a_rs = newBasicEntry.getCoefficient();
+  int a_rs_sgn = a_rs.sgn();
+  Rational negInverseA_rs = -(a_rs.inverse());
 
-void Row::printRow(){
-  Debug("tableau") << d_x_i << " ";
-  for(iterator nonbasicIter = d_coeffs.begin();
-      nonbasicIter != d_coeffs.end();
-      ++nonbasicIter){
-    ArithVar nb = nonbasicIter->first;
-    Debug("tableau") << "{" << nb << "," << d_coeffs[nb] << "}";
+  for(RowIterator i = basicRowIterator(basicOld); !i.atEnd(); ++i){
+    EntryID id = i.getID();
+    Tableau::Entry& entry = d_entries.get(id);
+
+    entry.getCoefficient() *=  negInverseA_rs;
   }
-  Debug("tableau") << std::endl;
+
+  d_basic2RowIndex.remove(basicOld);
+  d_basic2RowIndex.set(basicNew, rid);
+  d_rowIndex2basic.set(rid, basicNew);
+
+  cb.multiplyRow(rid, -a_rs_sgn);
 }
 
-void Tableau::addRow(ArithVar basicVar,
-                     const std::vector<Rational>& coeffs,
-                     const std::vector<ArithVar>& variables){
+void Tableau::addRow(ArithVar basic,
+                     const std::vector<Rational>& coefficients,
+                     const std::vector<ArithVar>& variables)
+{
+  Assert(basic < getNumColumns());
+  Assert(debugIsASet(variables));
+  Assert(coefficients.size() == variables.size());
+  Assert(!isBasic(basic));
+
+  RowIndex newRow = Matrix<Rational>::addRow(coefficients, variables);
+  addEntry(newRow, basic, Rational(-1));
+
+  Assert(!d_basic2RowIndex.isKey(basic));
+  Assert(!d_rowIndex2basic.isKey(newRow));
 
-  Assert(coeffs.size() == variables.size());
-  Assert(d_basicManager.isBasic(basicVar));
+  d_basic2RowIndex.set(basic, newRow);
+  d_rowIndex2basic.set(newRow, basic);
 
-  //The new basic variable cannot already be a basic variable
-  Assert(!isActiveBasicVariable(basicVar));
-  d_activeBasicVars.insert(basicVar);
-  Row* row_current = new Row(basicVar,coeffs,variables);
-  d_rowsTable[basicVar] = row_current;
 
-  //A variable in the row may have been made non-basic already.
-  //If this is the case we fake pivoting this variable
-  std::vector<Rational>::const_iterator coeffsIter = coeffs.begin();
-  std::vector<Rational>::const_iterator coeffsEnd = coeffs.end();
+  if(Debug.isOn("matrix")){ printMatrix(); }
 
-  std::vector<ArithVar>::const_iterator varsIter = variables.begin();
+  NoEffectCCCB noeffect;
+  NoEffectCCCB* nep = &noeffect;
+  CoefficientChangeCallback* cccb = static_cast<CoefficientChangeCallback*>(nep);
 
-  for( ; coeffsIter != coeffsEnd; ++coeffsIter, ++ varsIter){
+  vector<Rational>::const_iterator coeffIter = coefficients.begin();
+  vector<ArithVar>::const_iterator varsIter = variables.begin();
+  vector<ArithVar>::const_iterator varsEnd = variables.end();
+  for(; varsIter != varsEnd; ++coeffIter, ++varsIter){
     ArithVar var = *varsIter;
 
-    if(d_basicManager.isBasic(var)){
-      if(!isActiveBasicVariable(var)){
-        reinjectBasic(var);
-      }
-      Assert(isActiveBasicVariable(var));
+    if(isBasic(var)){
+      Rational coeff = *coeffIter;
 
-      Row* row_var = lookup(var);
-      row_current->substitute(*row_var);
+      RowIndex ri = basicToRowIndex(var);
+
+      loadRowIntoBuffer(ri);
+      rowPlusBufferTimesConstant(newRow, coeff, *cccb);
+      clearBuffer();
     }
   }
-}
 
-void Tableau::pivot(ArithVar x_r, ArithVar x_s){
-  Assert(d_basicManager.isBasic(x_r));
-  Assert(!d_basicManager.isBasic(x_s));
+  if(Debug.isOn("matrix")) { printMatrix(); }
 
-  Row* row_s = lookup(x_r);
-  Assert(row_s->has(x_s));
+  Assert(debugNoZeroCoefficients(newRow));
+  Assert(debugMatchingCountsForRow(newRow));
+  Assert(getColLength(basic) == 1);
+}
 
-  //Swap x_r and x_s in d_activeRows
-  d_rowsTable[x_s] = row_s;
-  d_rowsTable[x_r] = NULL;
+void Tableau::removeBasicRow(ArithVar basic){
+  RowIndex rid = basicToRowIndex(basic);
 
-  d_activeBasicVars.erase(x_r);
-  d_basicManager.makeNonbasic(x_r);
+  removeRow(rid);
+  d_basic2RowIndex.remove(basic);
+  d_rowIndex2basic.remove(rid);
+}
 
-  d_activeBasicVars.insert(x_s);
-  d_basicManager.makeBasic(x_s);
+void Tableau::substitutePlusTimesConstant(ArithVar to, ArithVar from, const Rational& mult,  CoefficientChangeCallback& cb){
+  if(!mult.isZero()){
+    RowIndex to_idx = basicToRowIndex(to);
+    addEntry(to_idx, from, mult); // Add an entry to be cancelled out
+    RowIndex from_idx = basicToRowIndex(from);
 
-  row_s->pivot(x_s);
+    cb.update(to_idx, from, 0, mult.sgn());
 
-  for(ArithVarSet::iterator basicIter = begin(), endIter = end();
-      basicIter != endIter; ++basicIter){
-    ArithVar basic = *basicIter;
-    Row* row_k = lookup(basic);
-    if(row_k->has(x_s)){
-      d_activityMonitor.increaseActivity(basic, 30);
-      row_k->substitute(*row_s);
-    }
+    loadRowIntoBuffer(from_idx);
+    rowPlusBufferTimesConstant(to_idx, mult, cb);
+    clearBuffer();
   }
 }
-void Tableau::printTableau(){
-  Debug("tableau") << "Tableau::d_activeRows"  << endl;
-
-  typedef RowsTable::iterator table_iter;
-  for(table_iter rowIter = d_rowsTable.begin(), end = d_rowsTable.end();
-      rowIter != end; ++rowIter){
-    Row* row_k = *rowIter;
-    if(row_k != NULL){
-      row_k->printRow();
-    }
+
+uint32_t Tableau::rowComplexity(ArithVar basic) const{
+  uint32_t complexity = 0;
+  for(RowIterator i = basicRowIterator(basic); !i.atEnd(); ++i){
+    const Entry& e = *i;
+    complexity += e.getCoefficient().complexity();
   }
+  return complexity;
 }
 
-
-void Tableau::updateRow(Row* row){
-  for(Row::iterator i=row->begin(), endIter = row->end(); i != endIter; ){
-    ArithVar var = i->first;
-    ++i;
-    if(d_basicManager.isBasic(var)){
-      Row* row_var = isActiveBasicVariable(var) ? lookup(var) : lookupEjected(var);
-
-      Assert(row_var != row);
-      row->substitute(*row_var);
-
-      i = row->begin();
-      endIter = row->end();
-    }
+double Tableau::avgRowComplexity() const{
+  double sum = 0;
+  uint32_t rows = 0;
+  for(BasicIterator i = beginBasic(), i_end = endBasic(); i != i_end; ++i){
+    sum += rowComplexity(*i);
+    rows++;
   }
+  return (rows == 0) ? 0 : (sum/rows);
 }
+
+void Tableau::printBasicRow(ArithVar basic, std::ostream& out){
+  printRow(basicToRowIndex(basic), out);
+}
+
+}  // namespace arith
+}  // namespace theory
+}  // namespace cvc5