On Wednesday 15 November 2006 12:55, Keith Goodman wrote: > I didn't know you could use masked arrays with matrices. I guess I > took the name literally.
:) Please check the developer zone: http://projects.scipy.org/scipy/numpy/wiki/MaskedArray for an alternative implementation of masked arrays that support subclasses of ndarray. > I think an easier way to use masked arrays would be to introduce a new > thing called mis. > > I could make a regular matrix > > x = M.rand(3,3) > > and assign a missing value > > x[0,0] = M.mis > > x would then behave as a missing array matrix. .... > I think that would make missing arrays accessible to everyone. Well, there's already something like that, sort of: MA.masked, or MA.masked_singleton. The emphasis here is on "sort of". That works well if x is already a masked array. Else, a "ValueError: setting an array element with a sequence" is raised. I haven't tried to find where the problem comes from (ndarray.__setitem__ ? The masked_singleton larger than it seems ?), but I wonder whether it's an issue worth solving. If you want to get a masked_matrix from x, just type x=masked_array(x). You won't be able to access some specific matrix attributes (A, T), at least directly, but you can fill your masked_matrix and get a matrix back. And multiplication of two masked_matrices work as expected ! The main advantage of this approach is that we don't overload ndarray or matrices, the work is solely on the masked_array side. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
