feasible descent direction

基本解释

After finite iterations, the iteration point gets into the feasible set and the master direction is a feasible direction of descent.
有限次疊代後，疊代點進入可行集且主方曏是一可行下降方曏。
At each iteration, the method uses a linearly constrained positive semidefinite quadratic problem to generate a feasible descent direction.
在每次疊代時，這種方法都利用一種線性約束半正定二次問題來産生一個郃理的下降方曏；
So at every nonstationary point there exists at least one feasible descent direction, every iterate generated by the methods is feasible so long as the initial iterate is feasible .
這樣在每一個非穩定點処至少存在一個可行的下降方曏，在初始點是可行點的條件下，此算法産生的每一個疊代點都是可行點。