DUPLICATE PATH break

[EmpRamses]

Hi, I've notice that some useless code in col-gen-vrptw.py from line 63 to 66. It seems that you want to exit the while loop if there is any duplicate path found by the subproblem. But the break only break down the for loop.

In my project on a variant VRP problem, I also notice that the column generation could always find out some duplicate routes with reduced cost less than zero, which makes the while loop never end. I have checked my cost function many times according to the exist paper and books. Should I exit the while loop if the subproblem output any duplicate paths? And do you have any references to support this kind of break?