[Numpy-discussion] masked array with mask an instance of numpy.memmap

[Pierre GM]

> Is there something deficient about numpy.core.ma?

numpy.core.ma objects are not ndarrays. Therefore, their mask disappear when 
used as the input of something like numpy.array(data, subok=True), which is 
quickly problematic. 
Moreover, they are not especially subclassing-friendly, which was my biggest 
bone, and the main reason why I started rewriting the implementation.