Two problems

[dzcaprime]

1. Package networkx has no attirbute "from_numpy_matrix".
   I use the new method "from_numpy_array" to construct the network instead. This works well.
2. PathCollection object has no attirbute "set_offset_position".
   I use the "collection.offset_position = "data" to replace the attribute. This also works.

However, the animation seems not so good because only a part of the network can be displayed in the fig. After I changed the figsize, the problem still exists. Maybe I should change some code in the process of frame generation.