removal of zero valued term from goal

PbSolver.C

@@ -71,9 +71,12 @@ void PbSolver::addInterestVars(int num)
     pb_i_vars = num; //reportf("pb_i_vars=%d\n",pb_i_vars); 
 }
 
-void PbSolver::addGoal(const vec<Lit>& ps, const vec<Int>& Cs)
+void PbSolver::addGoal(vec<Lit>& ps, vec<Int>& Cs)
 {
-    //**/debug_names = &index2name;
+
+  PbSolver::simplifyGoal(ps, Cs);
+  
+  //**/debug_names = &index2name;
     //**/reportf("MIN: "); dump(ps, Cs); reportf("\n");
   assert(ps.size() == Cs.size());
   assert(ps.size() >= 0);
@@ -442,6 +445,35 @@ bool PbSolver::normalizePb(vec<Lit>& ps, vec<Int>& Cs, Int& C, Lit llt)
     return true;
 }
 
+// Delete terms with zero coefficient
+
+void PbSolver::simplifyGoal(vec<Lit>& ps, vec<Int>& Cs)
+{
+  /*
+  bool hasZero = false;
+  for (int i = 0; i <ps.size(); i++){
+    if (Cs[i] == 0){
+      hasZero = true;
+      break;
+    }
+  }
+  */
+  //  if(hasZero){
+  int shrink = 0;
+  for (int i = 0; i <ps.size(); i++){
+    if (Cs[i] == 0) shrink++;
+    else if (shrink > 0) {
+      Cs[i-shrink] = Cs[i]; ps[i-shrink] = ps[i];
+    }
+  }
+  assert(ps.size() >= shrink);
+  //    if(ps.size() == shrink) shrink--;  // avoid null goal, leaving at least one 0*x.
+  if(shrink > 0){
+    ps.shrink(shrink); Cs.shrink(shrink);
+  }
+  //  }
+}
+
 bool PbSolver::rewritePureClause(const vec<Lit>& ps, const vec<Int>& Cs, Int lo, Int hi, Lit llt)
 {
         if(lo == Int_MIN && hi == Int_MAX) {  // true constraint

PbSolver.h

@@ -93,6 +93,7 @@ public:
     void    propagate();
     bool    addUnit  (Lit p) { return sat_solver.addUnit(p); }
     bool    normalizePb(vec<Lit>& ps, vec<Int>& Cs, Int& C, Lit llt=lit_Undef);
+    void    simplifyGoal(vec<Lit>& ps, vec<Int>& Cs);
     void    storePb    (const vec<Lit>& ps, const vec<Int>& Cs, Int lo, Int hi, Lit llp=lit_Undef);
     void    setupOccurs();   // Called on demand from 'propagate()'.
     void    findIntervals();
@@ -161,7 +162,7 @@ public:
     //
     int     getVar      (cchar* name);
     void    allocConstrs(int n_vars, int n_constrs);
-    void    addGoal     (const vec<Lit>& ps, const vec<Int>& Cs);
+    void    addGoal     (vec<Lit>& ps, vec<Int>& Cs);
     void    addInterestVars     (int num);
 
     /////////////////////