Active set strategy的用法和样例：
- 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.
- The following example returns the active SET options for the current connection.
- The optimality conditions are given and a road identification method based on active set algorithm is proposed.
- A value held by an operating system that indicates how much primary storage a process is likely to require for its active set during a particular phase of processing.