Hi,

We have a real symmetric matrix M with diagonal elements 0's, the eigenvalues and eigenvectors of M are computed.

Now we wish to change its diagonal elements arbitrarily to minimize the sum of absolute eigenvalues. Does there exist a way to find such modifications?

If we add a constraint : keep Tr(M)=0, would that become easier?

Is there some topics about these?

Thank you for your help

Zhi Ming