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

[Glen W. Mabey]

I've been using numpy.memmap to access large arrays very nicely, but now
I desire to instantiate a masked array that uses memmap objects.

Using a memmap instance for the data works just fine and as expected.

However, using a memmap for the mask value seems to load the entire
object into memory, even if it is already of type bool.

How hard would it be to change that behavior?

Also, it seems that median() is not implemented on masked arrays?

Is there some method for a masked array like ravel() but that only
includes the non-masked values?

Thank you,
Glen Mabey