ZeroDivisionError: float division

[kksspprr]

Hi,

the following code snippet works around 50% of the time and throws "ZeroDivisionError" 50% of the time.

forceatlas2 = ForceAtlas2(
# Behavior alternatives
outboundAttractionDistribution=True, # Dissuade hubs
linLogMode=False, # NOT IMPLEMENTED
adjustSizes=False, # Prevent overlap (NOT IMPLEMENTED)
edgeWeightInfluence=1.0,
# Performance
jitterTolerance=1.0, # Tolerance
barnesHutOptimize=True,
barnesHutTheta=1.2,
multiThreaded=False, # NOT IMPLEMENTED
# Tuning
scalingRatio=2.0,
strongGravityMode=False,
gravity=0.5,
# Log
verbose=True)

G = nx.complete_graph(2)

forceatlas2.forceatlas2_networkx_layout(G, pos=None, iterations=1000)

Output when it works:

0%| | 0/1000 [00:00<?, ?it/s]

0%| | 0/1000 [00:00<?, ?it/s]

100%|██████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 1000/1000 [00:00<00:00, 112015.38it/s]
BarnesHut Approximation took 0.00 seconds

Output when it doesn't work

0%| | 0/1000 [00:00<?, ?it/s]

0%| | 0/1000 [00:00<?, ?it/s]
ZeroDivisionError: float division

[victorbenichoux]

Hi,
Thanks for reporting this error.

Indeed, I can reproduce it here. It only seems to be the case for two nodes, and occurs because at some point coordinates for all nodes vanish (due to a combination of gravity and strong-connectedness), which makes the totalEffectiveTraction vanish as well and raise a ZeroDivisionError.
A similar error occurs when all positions are initialized to the same value.

I will open a pull request fixing these errors.

Victor