Store rank value for easy access
Store rank value for easy access

To avoid continually reaccessing the rank value in each rolling window
step forward, store it at the beginning and then reuse that value
throughout.

jakirkham/rank_filter,nanshe-org/rank_filter,jakirkham/rank_filter,DudLab/rank_filter,DudLab/rank_filter,jakirkham/rank_filter,DudLab/rank_filter,nanshe-org/rank_filter,nanshe-org/rank_filter