我通过IDE(5.5.2.0)传递给lp_solve的一个简单问题
/* Objective function */
max: +r1 +r2;
/* Constraints */
R1: +r1 +r2 <= 4;
R2: +r1 -2 b1 = 0;
R3: +r2 -3 b2 = 0;
/* Variable bounds */
b1 <= 1;
b2 <= 1;
/* Integer definitions */
int b1,b2;
这个问题的显而易见的解决方案是3. SCIP以及CBC给出3作为答案但不是lp_solve。我得到2.解算器中是否存在重大错误?
提前感谢。
答案 0 :(得分:1)
我与关心lpsolve软件的开发人员小组有过联系。该错误将在下一版本的lpsolve中修复。
答案 1 :(得分:0)
当我尝试它时,我得到3作为Obj函数的最佳值。
Model name: 'LPSolver' - run #1
Objective: Maximize(R0)
SUBMITTED
Model size: 3 constraints, 4 variables, 6 non-zeros.
Sets: 0 GUB, 0 SOS.
Using DUAL simplex for phase 1 and PRIMAL simplex for phase 2.
The primal and dual simplex pricing strategy set to 'Devex'.
Relaxed solution 4 after 4 iter is B&B base.
Feasible solution 2 after 6 iter, 3 nodes (gap 40.0%)
Optimal solution 2 after 7 iter, 4 nodes (gap 40.0%).
Excellent numeric accuracy ||*|| = 0
MEMO: lp_solve version 5.5.2.0 for 32 bit OS, with 64 bit REAL variables.
In the total iteration count 7, 1 (14.3%) were bound flips.
There were 2 refactorizations, 0 triggered by time and 0 by density.
... on average 3.0 major pivots per refactorization.
The largest [LUSOL v2.2.1.0] fact(B) had 8 NZ entries, 1.0x largest basis.
The maximum B&B level was 3, 0.8x MIP order, 3 at the optimal solution.
The constraint matrix inf-norm is 3, with a dynamic range of 3.
Time to load data was 0.001 seconds, presolve used 0.017 seconds,
... 0.007 seconds in simplex solver, in total 0.025 seconds.