fullfidelity is not my favorite name. Instead, we could define fidelity(::ITensor, ::ITensor), and then tell people to use fidelity(prod(rho), prod(sigma)). We can also define fidelity(::MPO, ::MPO) and just make it throw an error, telling people to use fidelity(::ITensor, ::ITensor) instead.
fullfidelity
is not my favorite name. Instead, we could definefidelity(::ITensor, ::ITensor)
, and then tell people to usefidelity(prod(rho), prod(sigma))
. We can also definefidelity(::MPO, ::MPO)
and just make it throw an error, telling people to usefidelity(::ITensor, ::ITensor)
instead.