message: Fix the serial example 19
diff: @@ -84,9 +84,6 @@ protected:
  // Block nonlinear form
  BlockNonlinearForm *Hform;
  - // Jacobian of the nonlinear form
  - mutable Operator *jacobian;
  -
  // Pressure mass matrix for the preconditioner
  SparseMatrix *pressure_mass;
  @@ -319,7 +316,7 @@ JacobianPreconditioner::JacobianPreconditioner(Array<FiniteElementSpace *> &fes,
  mass_pcg_iter->SetMaxIter(200);
  mass_pcg_iter->SetPrintLevel(0);
  mass_pcg_iter->SetPreconditioner(*mass_prec);
  - mass_pcg_iter->iterative_mode = true;
  + mass_pcg_iter->iterative_mode = false;
  mass_pcg = mass_pcg_iter;
  @@ -349,9 +346,8 @@ void JacobianPreconditioner::Mult(const Vector &k, Vector &y) const
  Vector temp2(block_offsets[1]-block_offsets[0]);
  // Perform the block elimination for the preconditioner
  - pres_in *= -1.0 * gamma;
  -
  mass_pcg->Mult(pres_in, pres_out);
  + pres_out *= -gamma;
  jacobian->GetBlock(0,1).Mult(pres_out, temp);
  subtract(disp_in, temp, temp2);
  @@ -387,7 +383,7 @@ void JacobianPreconditioner::SetOperator(const Operator &op)
  stiff_pcg_iter->SetPrintLevel(0);
  stiff_pcg_iter->SetPreconditioner(*stiff_prec);
  stiff_pcg_iter->SetOperator(jacobian->GetBlock(0,0));
  - stiff_pcg_iter->iterative_mode = true;
  + stiff_pcg_iter->iterative_mode = false;
  stiff_pcg = stiff_pcg_iter;
  @@ -481,9 +477,7 @@ void RubberOperator::Mult(const Vector &k, Vector &y) const
  // Compute the Jacobian from the nonlinear form
  Operator &RubberOperator::GetGradient(const Vector &xp) const
  {
  - jacobian = &Hform->GetGradient(xp);
  -
  - return *jacobian;
  + return Hform->GetGradient(xp);
  }
  RubberOperator::~RubberOperator()
  