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| The OPTMILP Procedure |
| Node Log |
The following information about the status of the branch-and-bound algorithm is printed in the node log:
- Node
indicates the sequence number of the current node in the search tree.
- Active
indicates the current number of active nodes in the branch-and-bound tree.
- Sols
indicates the number of feasible solutions found so far.
- BestInteger
indicates the best upper bound (assuming minimization) found so far.
- BestBound
indicates the best lower bound (assuming minimization) found so far.
- Gap
indicates the relative gap between BestInteger and BestBound, displayed as a percentage. If the relative gap is larger than 1000, then the absolute gap is displayed. If there are no active nodes remaining, the value of Gap is 0.
- Time
indicates the elapsed real time.
The PRINTFREQ= and PRINTLEVEL2= options can be used to control the amount of information printed in the node log. By default a new entry is included in the log at the first node, at the last node, and at 100-node intervals. A new entry is also included each time a better integer solution is found. The PRINTFREQ= option enables you to change the interval between entries in the node log. Figure 18.4 shows a sample node log.
| The OPTMILP Procedure |
| Constraint Information |
NOTE: The problem ex1data has 10 variables (0 binary, 10 integer, 0 free, 0 |
fixed). |
NOTE: The problem has 2 constraints (2 LE, 0 EQ, 0 GE, 0 range). |
NOTE: The problem has 20 constraint coefficients. |
NOTE: The OPTMILP presolver value AUTOMATIC is applied. |
NOTE: The OPTMILP presolver removed 0 variables and 0 constraints. |
NOTE: The OPTMILP presolver removed 0 constraint coefficients. |
NOTE: The OPTMILP presolver modified 0 constraint coefficients. |
NOTE: The presolved problem has 10 variables, 2 constraints, and 20 constraint |
coefficients. |
NOTE: The MIXED INTEGER LINEAR solver is called. |
Node Active Sols BestInteger BestBound Gap Time |
0 1 1 0 88.0955497 100.00% 0 |
0 1 2 83.0000000 87.9082814 5.58% 0 |
0 1 3 85.0000000 87.8376960 3.23% 0 |
0 1 4 85.0000001 87.8367613 3.23% 0 |
0 1 4 85.0000001 87.8335246 3.23% 0 |
0 1 4 85.0000001 87.7943346 3.18% 0 |
NOTE: OPTMILP added 3 cuts with 30 cut coefficients at the root. |
1 2 5 86.0000000 87.7705030 2.02% 0 |
4 0 6 87.0000000 . 0.00% 0 |
NOTE: Optimal. |
NOTE: Objective = 87. |
NOTE: The data set WORK.EX1SOLN has 10 observations and 8 variables. |
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