1. In a machine-effected method of creating a schedule to a given schedule problem, which has to satisfy the constraints and maximize a user's objectives in the schedule that are or are not described explicitly in the schedule problem; the machine-executed steps of: first, acquiring and recording the user's context dependent preferential knowledge for scheduling, in a case library, by solving trial schedule problems with extensive assistance of a user, said case library including schedule evaluation information, repairability information, and repair history information; second, solving new schedule problems by reusing the recorded user's context dependent preferential knowledge stored in said case library in the decision points of the new schedule problems.