On Wednesday 21 May 2008 17:57:30 Charles R Harris wrote: > On Wed, May 21, 2008 at 3:10 PM, Charles R Harris > <[EMAIL PROTECTED]> > > wrote: > > On Wed, May 21, 2008 at 2:39 PM, Charles R Harris < > > > > [EMAIL PROTECTED]> wrote: > >> On Wed, May 21, 2008 at 10:07 AM, Alan McIntyre > >> <[EMAIL PROTECTED]> > >> > >> wrote: > >>> On Wed, May 21, 2008 at 11:56 AM, Pierre GM <[EMAIL PROTECTED]> > >>> > >>> wrote: > >>> > On Wednesday 21 May 2008 11:39:32 Alan McIntyre wrote: > >>> >> There's some commentary and a patch on NumPy ticket 793 on this > >>> >> issue: > >>> >> > >>> >> http://scipy.org/scipy/numpy/ticket/793 > >>> > > >>> > OK, thanks a lot ! That's a C problem, then... > >>> > >>> It's probably worth mentioning that I'm not that familiar with all the > >>> innards of NumPy yet, so take my comments and patch on that issue with > >>> a (fairly large) grain of salt. ;) > >> > >> This was introduced by Travis in r5138 as part of the matrix changes. > > > > Alan's change looks a bit iffy to me because the looser check would pass > > things like matrices and there would be no check for decreasing > > dimensions to throw an error. So I think the safest thing for 1.1 is to > > back out Travis' change and rethink this for 1.2. > > > > Chuck > > I backed out r5138 and, with a few test fixes, everything passes. However, > there is now a warning exposed in the masked array tests: > > /usr/lib/python2.5/site-packages/numpy/ma/core.py:1357: UserWarning: > MaskedArray.__setitem__ on fields: The mask is NOT affected! > warnings.warn("MaskedArray.__setitem__ on fields: " > > Pierre?
Well, that's a warning all right, not an error. With "exotic" dtypes (understand, not int,bool,float or complex but named fields), setting a field doesn't affect the mask, hence the warning. The reason behind this behavior is that the mask of a MaskedArray is only a boolean-array: you have (at most) one boolean per element/record. Therefore, you can mask/unmask a full record, but not a specific field. Masking particular fields is possible with MaskedRecords, however, but with an overhead that wasn't worth putting in MaskedArray. Because I've been bitten a couple of times by this mechanism, I figured that a warning would be the easiest way to remember that MaskedArrays don't handle records very well. So, nothing to worry about. _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
