Editing numbers of cut

[aleraguz]

Is there any possibility to change the numbers of cuts used by Concorde to solve TSP? I mean, I think it is currently working con 16 cuts, can I change to 25 for example?

[jvkersch]

Hmm, not sure. I'd have to look into that...

[aleraguz]

What I've figured out, so far, is a function called "usage" in concorde.c . In this function is basically explained the same thing you can find running concorde by command windows, if you put "-C 24" it will run the program adding 24 local cuts. However I could find a way to invoke it in the code.

[jvkersch]

@aleraguz That's a good find, thanks! It shouldn't be too difficult to expose that option on the Python side.

[aleraguz]

To be honest I was finding this information because I got some non-exact solution using Concorde and at the beginning I thought it was because of the numbers of local cutting planes. Actually, this problem arises if you set coordinates with many decimal numbers cause of Concorde's huge approximation errors. Thus, basically, just multiply all the distances by 100 or 1000.

[jvkersch]

@aleraguz Thanks for the find, and sorry it took me so long to get back to this.

I wanted to point out that the 0.2.0 API will run concorde in a subprocess, which will make it much easier to pass arbitrary options to the solver. See #28 (comment) for details.