diff -r 48b4f46f9d4e -r ad44b1dd8013 src/lemon/lp_glpk.cc
--- a/src/lemon/lp_glpk.cc	Thu May 19 11:53:25 2005 +0000
+++ b/src/lemon/lp_glpk.cc	Fri May 20 09:31:25 2005 +0000
@@ -87,7 +87,43 @@
 		    const_cast<int * >(indices),
 		    const_cast<Value * >(values));
   }
-  
+
+
+  void LpGlpk::_setCoeff(int row, int col, Value value) 
+  {
+    ///FIXME Of course this is not efficient at all, but GLPK knows not more.
+    // First approach: get one row, apply changes and set it again
+    //(one idea to improve this: maybe it is better to do this with 1 coloumn)
+    
+    int mem_length=2+lpx_get_num_cols(lp);
+    int* indices = new int[mem_length];
+    Value* values = new Value[mem_length];
+    
+
+    int length=lpx_get_mat_row(lp, row, indices, values);
+
+    //The following code does not suppose that the elements of the array indices are sorted
+    int i=1;
+    bool found=false;
+    while (i <= length && !found){
+      if (indices[i]==col){
+	found = true;
+	values[i]=value;
+      }
+      ++i;
+    }
+    if (!found){
+      ++length;
+      indices[length]=col;
+      values[length]=value;
+    }
+    
+    lpx_set_mat_row(lp, row, length, indices, values);
+    delete [] indices;
+    delete [] values;
+    
+  }
+
   void LpGlpk::_setColLowerBound(int i, Value lo)
   {
     if (lo==INF) {