By using active set strategy, the authors need only to solve a reduced trust region subproblem which is solved inexactly by the truncated conjugate gradient method.

• 作者利用有效集策略，在每次迭代中只需求解一个低维的信赖域子问题，该信赖域子问题是通过截断共轭梯度法来近似求解的。