# Exponential of MPO

Hi,

So I've been trying to use this function: expHermitian(ITensor H, Cplx tau = 1)
but the operator that I want to exponentiate is the total Sz. Here is the code that I have so far:

auto ampo2 = AutoMPO(sites); for(auto k : range1(Nspins)) { ampo2 += "Sz",k; } auto proj = toMPO(ampo2); auto exp2H = expHermitian(proj,2);

but I get an error that the function expects an ITensor object as the first argument (as expected). Is it possible to somehow do what I am trying to do?

Thank you.

commented by (390 points)
I am sorry, I just realized that there is a new forum, just posted it there.
commented by (70.1k points)
Yes, thanks!