Segfault when using --cluster-data with a tree file

[antoneri]

The following creates a segfault:

infomap --no-infomap validation_seed0_order2.net --cluster-data training_seed0_order2.tree .

validation_seed0_order2.net
training_seed0_order2.tree

======================================================
  Infomap v1.0.7 starts at 2020-03-11 16:13:06
  -> Input network: validation_seed0_order2.net
  -> Output path:   ./
  -> Configuration: cluster-data = training_seed0_order2.tree
                    no-infomap
=======================================================
Parsing undirected network from file 'validation_seed0_order2.net'...
  Parsing vertices...
  -> 12 physical nodes added
  Parsing state nodes...
  -> 12 state nodes added
  Parsing links...
  -> 82 links
Done!
-------------------------------------
  -> 12 state nodes
  -> 12 physical nodes
  -> 82 links with total weight 5005
  -> Found higher order network input, using the Map Equation for higher order network flows
Calculating global network flow using flow model 'undirected'...
  -> Using undirected links.
  => Sum node flow: 1, sum link flow: 1
Build internal network with 12 nodes and 82 links...
Calculating one-level codelength... done!
 -> One-level codelength: 3.54274544
Calculating entropy rate... done!
  -> Entropy rate: 2.801735967

================================================
Trial 1/1 starting at 2020-03-11 16:13:06
================================================
Init partition from file 'training_seed0_order2.tree'... Warning, aggregated flow is not exactly 1.0, but 0.
done! Generated 0 levels with codelength 0

=> Trial 1/1 finished in 0.000349s with codelength 0
Segmentation fault (core dumped)