Forum Discussion
How can I modify Knitro parameters via Xpress?
Hi all,
I am trying to modify the following Knitro parameters but I have troubles with both of them.
1) XKTR_PARAM_MIP_INTEGERTOL: although the parameter is described in xpress reference manual, my mosel file doesn't compile returning the error E-122 ("Control parameter `XKTR_PARAM_MIP_INTEGERTOL' unknown.")
2) XKTR_PARAM_PAR_NUMTHREADS: this parameter should make Knitro use several threads. When I solve the model loading the .mps in xpress optimizer console, Knitro runs with multiple threads but when I run my mosel file it doesn't, even though the parameter looks correctly set.
More in general, is there any module I should add to my mosel file in order to get access to all the parameters that Knitro has?
Thank you in advance.
Br, Caterina
3 Replies
Could you please show a minimal example that reproduces your problem? Especially for the INTERNTOL case in which the parameter is not even found.
Hi Caterina,
to add to what Daniel said:
1) The Integer tolerance is unfortunately indeed not supported through Xpress at the moment, even though it is mentioned in the documentation, we will look into supporting it in a future release.
2) Here indeed an example would be good to be able to double-check this on our side.
Hi all,
thanks for all your answers and sorry for the late reply.
1) Ok, now I see why I got that error.
2) I solved this "issue" with a colleague of mine: when solving a MINLP Knitro uses multiple threads for the branch and bound algorithm, not for the multistart procedure that solves the relaxation of each node.
Have a nice day!
