Hi Tiago, A new error message: Running: import graph_tool.all as gt import numpy as np import cPickle as pickle import timeit g = gt.load_graph('graph_no_multi_1950.gt') with open('model_selection_results_1950.dat','w') as output: deg_corr = False overlap = True nL = 10 # Initialize the Markov chain from the "ground state" state = gt.minimize_nested_blockmodel_dl(g, deg_corr=deg_corr,overlap=overlap) print 'minimised state' bs = state.get_bs() # Get hierarchical partition. bs += [np.zeros(1)] * (nL - len(bs)) # Augment it to L = 10 with # single-group levels. state = state.copy(bs=bs, sampling=True) Returns the following error message: Traceback (most recent call last): File "model_class_selection_nested_ndc_o.py", line 27, in <module> state = state.copy(bs=bs, sampling=True) File "/home/pmj27/anaconda2/lib/python2.7/site-packages/graph_tool/inference/nested_blockmodel.py", line 146, in copy **kwargs) File "/home/pmj27/anaconda2/lib/python2.7/site-packages/graph_tool/inference/nested_blockmodel.py", line 90, in __init__ nb[:len(b)] = b ValueError: could not broadcast input array from shape (63754) into shape (15643) Here is the graph ( graph_no_multi_1950_clean.zip <http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/file/n4027153/graph_no_multi_1950_clean.zip> ) and the script ( model_class_selection_nested_ndc_o.py <http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/file/n4027153/model_class_selection_nested_ndc_o.py> ). The graph-tool version is 2.23dev (commit 8c8fa901, Mon Mar 6 16:13:20 2017 +0100). Do you know what this might be caused by? Best, Philipp -- View this message in context: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/... Sent from the Main discussion list for the graph-tool project mailing list archive at Nabble.com.