Forum Discussion
Implementing Lazy Constraints (Java)
We are interested in using Lazy Constraints in Xpress (Java) to implement a TSP algorithm. In particular, after each integer solution is generated, we would like to search for violated constraints an...
CUT(0):- 586*x_0,1,0 - t_0 + t_1 >= 558
CUT(0):- 636*x_2,5,23 - t_2 + t_5 >= 558
CUT(0):- 606*x_4,2,20 + t_2 - t_4 >= 558
CUT(0):- 595*x_6,3,9 + t_3 - t_6 >= 558
CUT(0):- 561*x_7,8,31 - t_7 + t_8 >= 558
BCL: Warning 1587: Switch to cut mode.
BCL: Warning 1570: XPRS: ?405 Error: Invalid column number passed to XPRSaddcuts.
Column number 2048 is invalid
Exception in thread "main" com.dashoptimization.XPRBerror: (addcuts) Xpress-Optimizer error 405 during 'addcuts'. Return value: 32.
Any ideas? I switched over to using cuts and added them at the end. All cuts are valid for the problem, but maybe Xpress doesn't like them since the current solution to be accepted is violated by them.