doc_topic not init in function transform

[lpoyster]

doc_topic is init from numpy.empty, when input is all zero, the func _transform_single will not execute, then doc_topic will return without inited.

[ariddell]

Thanks. It does look like this case isn't handled.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.