Why the optimal value decreases first and then increases?

Why should that not be case?

I see no reason why that could not happen given the information you provide.

I want to minimize a function, i think the optimal value should always decrease. I am confused.

You showed us the output of two problem,s, but didn’t tell us the relationship between the problems. So we have no idea what is going on.

If you are using SCA, then anything is possible, because the sequence of results can do almost anything. You were warned about SCA in a previous thread Can quad_over_lin solve this problem? .

Thanks! The above situation may not a problem, i will focus on other aspects.