  We review different tensor network approaches to study the spreading of
operators in generic nonintegrable quantum systems. As a common ground to all
methods, we quantify this spreading by means of the Frobenius norm of the
commutator of a spreading operator with a local operator, which is usually
referred to as the out of time order correlation (OTOC) function. We compare
two approaches based on matrix-product states in the Schr\"odinger picture: the
time dependent block decimation (TEBD) and the time dependent variational
principle (TDVP), as well as TEBD based on matrix-product operators directly in
the Heisenberg picture. The results of all methods are compared to numerically
exact results using Krylov space exact time evolution. We find that for the
Schr\"odinger picture the TDVP algorithm performs better than the TEBD
algorithm. Moreover the tails of the OTOC are accurately obtained both by TDVP
MPS and TEBD MPO. They are in very good agreement with exact results at short
times, and appear to be converged in bond dimension even at longer times.
However the growth and saturation regimes are not well captured by both
methods.
