g = gt.collection.data["lesmis"]

clabel = g.vp["clabel"] = g.new_vp("int")

for v in g.vertices():

    clabel[v]=np.random.randint(3)

    

state = gt.NestedBlockState(g, state_args={'clabel':clabel,'pclabel':clabel})

for i in range(100):

    state.multiflip_mcmc_sweep(niter=10)

If it helps, I’m getting the same problem with the following changes:

- use equilibrate instead of multiflip.

- use two labels instead of three.

- use minimize_nested_blockmodel_dl instead of NestedBlockState

- pass clabels dictionary as **args

Extra information:

- If I run the multifip MCMC fewer times (let’s say 10) sometimes it works, sometimes it doesn’t, so it seems that the error is somewhat stochastic.

- This happens on different machines, both with Linux and Mac

Is this a bug or am I doing something wrong?

Best,

Valerio