[Numpy-discussion] Uncomfortable with matrix change

Bruce Southey bsouthey@gmail....
Fri May 9 10:27:51 CDT 2008


Charles R Harris wrote:
>
>
> On Fri, May 9, 2008 at 8:51 AM, Bruce Southey <bsouthey@gmail.com 
> <mailto:bsouthey@gmail.com>> wrote:
>
>     Charles R Harris wrote:
>     >
>     >
>     > On Fri, May 9, 2008 at 7:43 AM, Travis Oliphant
>     <teoliphant@gmail.com <mailto:teoliphant@gmail.com>
>     > <mailto:teoliphant@gmail.com <mailto:teoliphant@gmail.com>>> wrote:
>     >
>     >
>     >     Hi all,
>     >
>     >     I'm having trouble emailing this list from work, so I'm using a
>     >     different email address.
>     >
>     >     After Nathan Bell's recent complaints, I'm a bit more
>     >     uncomfortable with
>     >     the matrix change to scalar indexing.   It does and will
>     break code in
>     >     possibly hard-to-track down ways.   Also, Nathan has been a
>     *huge*
>     >     contributor to the Sparse matrix in scipy and so I value his
>     opinion
>     >     about the NumPy matrix.  One of my goals is to have those
>     two objects
>     >     work together a bit more seamlessly.
>     >
>     >     So, I think we need to:
>     >
>     >     1) Add a warning to scalar access
>     >     2) Back-out the change and fix all the places where NumPy
>     assumes
>     >     incorrectly that the number of dimensions reduce on
>     >     PySequence_GetItem.
>     >
>     >
>     > -1.
>     >
>     > That said, the basic mistake is probably making Matrix a subclass of
>     > ndarray, as it fails the "is a" test. There really aren't that many
>     > places where inheritance is the right choice and  numpy itself
>     wasn't
>     > designed as a base class: it lacks a specification of what functions
>     > can be "virtual" and is probably too big.
>     >
>     > I vote that we bring Nathan into the conversation and see how
>     upset he
>     > really is. Speaking for myself, I sometimes get angry upfront when
>     > specifications change unexpectedly underfoot but then settle
>     down and
>     > find that it isn't all that bad. Being caught by surprise is
>     probably
>     > half the problem.
>     >
>     > Chuck
>     >
>     >
>     >
>     ------------------------------------------------------------------------
>     >
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>     >
>     Hi,
>     +1
>
>     The prime reason is not whether or not it is a bad/good idea but
>     because
>     the actual change was introduced so late in the development of
>     1.0.5/1.1
>     process. A lesser reason is that gives people like Nathan time to
>     change
>     their code to match the pending release. Unfortunately the other
>     problem
>     with this change is that any user now has to be careful of which NumPy
>     version is being used. The result is that backwards compatibility
>     is now
>     broken in what was originally going to be a minor release.
>
>
> Of course, if Nathan has already made the changes we will drive him 
> crazy if we back them out now ;) I note that the thread on scipy ended 
> pretty quickly, so I didn't get the impression there was a lot of 
> resistance.
>
Sure all the related threads ended abruptly perhaps related to the fact 
that Travis suggested the change :-)


Bruce



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