Are there any packages there any LDA packages out there that allow you to specify the full asymmetric prior? I know Mallet uses asymmetric priors, but I don't believe it allows you to specify them.
alpha can be set to an explicit array = prior of your choice. It also support special values of ‘asymmetric’ and ‘auto’: the former uses a fixed normalized asymmetric 1.0/topicno prior, the latter learns an asymmetric prior directly from your data.
Hope that helps!