Index: lemon/cbc.cc
===================================================================
--- lemon/cbc.cc	(revision 623)
+++ lemon/cbc.cc	(revision 793)
@@ -95,4 +95,16 @@
   }
 
+  int CbcMip::_addRow(Value l, ExprIterator b, ExprIterator e, Value u) {
+    std::vector<int> indexes;
+    std::vector<Value> values;
+
+    for(ExprIterator it = b; it != e; ++it) {
+      indexes.push_back(it->first);
+      values.push_back(it->second);
+    }
+
+    _prob->addRow(values.size(), &indexes.front(), &values.front(), l, u);
+    return _prob->numberRows() - 1;
+  }
 
   void CbcMip::_eraseCol(int i) {
Index: lemon/cbc.h
===================================================================
--- lemon/cbc.h	(revision 623)
+++ lemon/cbc.h	(revision 793)
@@ -63,4 +63,5 @@
     virtual int _addCol();
     virtual int _addRow();
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
 
     virtual void _eraseCol(int i);
Index: lemon/clp.cc
===================================================================
--- lemon/clp.cc	(revision 623)
+++ lemon/clp.cc	(revision 793)
@@ -79,4 +79,17 @@
   }
 
+  int ClpLp::_addRow(Value l, ExprIterator b, ExprIterator e, Value u) {
+    std::vector<int> indexes;
+    std::vector<Value> values;
+
+    for(ExprIterator it = b; it != e; ++it) {
+      indexes.push_back(it->first);
+      values.push_back(it->second);
+    }
+
+    _prob->addRow(values.size(), &indexes.front(), &values.front(), l, u);
+    return _prob->numberRows() - 1;
+  }
+
 
   void ClpLp::_eraseCol(int c) {
Index: lemon/clp.h
===================================================================
--- lemon/clp.h	(revision 623)
+++ lemon/clp.h	(revision 793)
@@ -76,4 +76,5 @@
     virtual int _addCol();
     virtual int _addRow();
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
 
     virtual void _eraseCol(int i);
Index: lemon/cplex.cc
===================================================================
--- lemon/cplex.cc	(revision 623)
+++ lemon/cplex.cc	(revision 793)
@@ -112,4 +112,37 @@
   }
 
+  int CplexBase::_addRow(Value lb, ExprIterator b, 
+                         ExprIterator e, Value ub) {
+    int i = CPXgetnumrows(cplexEnv(), _prob);
+    if (lb == -INF) {
+      const char s = 'L';
+      CPXnewrows(cplexEnv(), _prob, 1, &ub, &s, 0, 0);
+    } else if (ub == INF) {
+      const char s = 'G';
+      CPXnewrows(cplexEnv(), _prob, 1, &lb, &s, 0, 0);
+    } else if (lb == ub){
+      const char s = 'E';
+      CPXnewrows(cplexEnv(), _prob, 1, &lb, &s, 0, 0);
+    } else {
+      const char s = 'R';
+      double len = ub - lb;
+      CPXnewrows(cplexEnv(), _prob, 1, &lb, &s, &len, 0);
+    }
+
+    std::vector<int> indices;
+    std::vector<int> rowlist;
+    std::vector<Value> values;
+
+    for(ExprIterator it=b; it!=e; ++it) {
+      indices.push_back(it->first);
+      values.push_back(it->second);
+      rowlist.push_back(i);
+    }
+
+    CPXchgcoeflist(cplexEnv(), _prob, values.size(),
+                   &rowlist.front(), &indices.front(), &values.front());
+
+    return i;
+  }
 
   void CplexBase::_eraseCol(int i) {
Index: lemon/cplex.h
===================================================================
--- lemon/cplex.h	(revision 623)
+++ lemon/cplex.h	(revision 793)
@@ -94,4 +94,5 @@
     virtual int _addCol();
     virtual int _addRow();
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
 
     virtual void _eraseCol(int i);
Index: lemon/glpk.cc
===================================================================
--- lemon/glpk.cc	(revision 623)
+++ lemon/glpk.cc	(revision 793)
@@ -57,4 +57,40 @@
     int i = glp_add_rows(lp, 1);
     glp_set_row_bnds(lp, i, GLP_FR, 0.0, 0.0);
+    return i;
+  }
+
+  int GlpkBase::_addRow(Value lo, ExprIterator b, 
+                        ExprIterator e, Value up) {
+    int i = glp_add_rows(lp, 1);
+
+    if (lo == -INF) {
+      if (up == INF) {
+        glp_set_row_bnds(lp, i, GLP_FR, lo, up);
+      } else {
+        glp_set_row_bnds(lp, i, GLP_UP, lo, up);
+      }    
+    } else {
+      if (up == INF) {
+        glp_set_row_bnds(lp, i, GLP_LO, lo, up);
+      } else if (lo != up) {        
+        glp_set_row_bnds(lp, i, GLP_DB, lo, up);
+      } else {
+        glp_set_row_bnds(lp, i, GLP_FX, lo, up);
+      }
+    }
+
+    std::vector<int> indexes;
+    std::vector<Value> values;
+
+    indexes.push_back(0);
+    values.push_back(0);
+
+    for(ExprIterator it = b; it != e; ++it) {
+      indexes.push_back(it->first);
+      values.push_back(it->second);
+    }
+
+    glp_set_mat_row(lp, i, values.size() - 1,
+                    &indexes.front(), &values.front());
     return i;
   }
Index: lemon/glpk.h
===================================================================
--- lemon/glpk.h	(revision 697)
+++ lemon/glpk.h	(revision 793)
@@ -55,4 +55,5 @@
     virtual int _addCol();
     virtual int _addRow();
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
 
     virtual void _eraseCol(int i);
Index: lemon/lp_base.h
===================================================================
--- lemon/lp_base.h	(revision 631)
+++ lemon/lp_base.h	(revision 793)
@@ -944,4 +944,12 @@
     virtual int _addRow() = 0;
 
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u) {
+      int row = _addRow();
+      _setRowCoeffs(row, b, e);
+      _setRowLowerBound(row, l);
+      _setRowUpperBound(row, u);
+      return row;
+    }
+
     virtual void _eraseCol(int col) = 0;
     virtual void _eraseRow(int row) = 0;
@@ -1208,6 +1216,8 @@
     ///\return The created row.
     Row addRow(Value l,const Expr &e, Value u) {
-      Row r=addRow();
-      row(r,l,e,u);
+      Row r;
+      e.simplify();
+      r._id = _addRowId(_addRow(l - *e, ExprIterator(e.comps.begin(), cols),
+                                ExprIterator(e.comps.end(), cols), u - *e));
       return r;
     }
@@ -1218,6 +1228,10 @@
     ///\return The created row.
     Row addRow(const Constr &c) {
-      Row r=addRow();
-      row(r,c);
+      Row r;
+      c.expr().simplify();
+      r._id = _addRowId(_addRow(c.lowerBounded()?c.lowerBound():-INF, 
+                                ExprIterator(c.expr().comps.begin(), cols),
+                                ExprIterator(c.expr().comps.end(), cols),
+                                c.upperBounded()?c.upperBound():INF));
       return r;
     }
Index: lemon/lp_skeleton.cc
===================================================================
--- lemon/lp_skeleton.cc	(revision 623)
+++ lemon/lp_skeleton.cc	(revision 793)
@@ -29,4 +29,9 @@
 
   int SkeletonSolverBase::_addRow()
+  {
+    return ++row_num;
+  }
+
+  int SkeletonSolverBase::_addRow(Value, ExprIterator, ExprIterator, Value)
   {
     return ++row_num;
Index: lemon/lp_skeleton.h
===================================================================
--- lemon/lp_skeleton.h	(revision 623)
+++ lemon/lp_skeleton.h	(revision 793)
@@ -45,4 +45,6 @@
     /// \e
     virtual int _addRow();
+    /// \e
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
     /// \e
     virtual void _eraseCol(int i);
Index: lemon/soplex.cc
===================================================================
--- lemon/soplex.cc	(revision 623)
+++ lemon/soplex.cc	(revision 793)
@@ -92,4 +92,17 @@
   }
 
+  int SoplexLp::_addRow(Value l, ExprIterator b, ExprIterator e, Value u) {
+    soplex::DSVector v;
+    for (ExprIterator it = b; it != e; ++it) {
+      v.add(it->first, it->second);
+    }
+    soplex::LPRow r(l, v, u);
+    soplex->addRow(r);
+
+    _row_names.push_back(std::string());
+
+    return soplex->nRows() - 1;
+  }
+
 
   void SoplexLp::_eraseCol(int i) {
Index: lemon/soplex.h
===================================================================
--- lemon/soplex.h	(revision 623)
+++ lemon/soplex.h	(revision 793)
@@ -85,4 +85,5 @@
     virtual int _addCol();
     virtual int _addRow();
+    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
 
     virtual void _eraseCol(int i);
