1, the establishment and solution of the model, xi = 1 means nine courses arranged in numerical order in the elective table 1 (xi =0 means not to choose; I = 1, 2, ... 9). The goal of the problem is to have the least elective courses.

2. Take (1. 1) as the objective function and (1.2) ~ (1.10) as the constraint condition, and input this model into LINGO (.

3. Other variables are 0. According to the course number, they are calculus, linear algebra, optimization method, computer simulation, computer programming and mathematical experiment, with a total score of 2 1.

Conceptual analysis

When using @POSD function, the function of conic solver option is enhanced by adding SDP)/ POSD function. For example, to estimate the combination of covariance matrices, the @POSD function can be used to force the matrix to be semi-positive, which is a necessary property of any covariance matrix.

The cutting improvement related to knapsack problem obviously improves the solving speed of some knapsack problem models. The improved default node selection rule enhances the performance of most integer programming models.