nanshe/util/xnumpy.py: Skip coversion in `pair_dot_product_partially_normalized` if already `float64`.
nanshe/util/xnumpy.py: Skip coversion in `pair_dot_product_partially_normalized` if already `float64`.

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