Original Date: 11/5/2023

I’ve been working with QUBOs for almost two years now. I almost always try to formulate a problem as a QUBO because that is what my job requires. If the problem does not fit into a QUBO, then it is not a problem I spend much time trying to solve because it won’t benefit my employer.

I recently faced an optimization problem, a project proposal with estimated effort and resource assignments. This was not a customer project. Normally, I would have had solved this with networkx or cbc. The problem would have been a piece of cake for either one. I used a QUBO formulation and an analog device to solve it. The QUBO formulation took some additional steps to prepare the problem, but those steps are ingrained in memory now.

The device is remote, so that’s one more reason that I might have chosen to use a different tool. A local tool could solve this simple problem in the time it takes me to send the QUBO to the device. Does this matter? Of course it matters. But, does it make a difference? In this situation, no. I am multitasking, so it does not make me less productive to spend the extra time to send the problem to a remote computer.

If the problem takes 10 seconds or 30 seconds, it is the same result. If the problem is solved by the time I need the answer, then that is all I care about.