[Matrix-SIG] RE: Numeric Nits

[Joe Harrington]

A good posting from the STScI folks.  I agree that Numeric must pay
attention to speed and memory usage issues, even if Python doesn't.
In an ideal world, these practical concerns and their solutions would
be fed back to Guido and future language authors, whose professional
experience with these issues is evidently rather limited.  People have
been talking about these problems since at least the late 1960s, when
"double" became the default type for scientific notation in C and
Fortran programs and all casts were up.

That said, working with 16k**2 images is inherently hard, and to do so
well will require a solution like what Saoimage, Gimp, Adobe
Illustrator, and other image programs provide, namely indexed
subsampling.  You make a subsampled image that the user looks at on
screen and does sample calculations on.  When you're happy with the
results there, you do the calculations on the full image.  In
visualization programs, you can run a magnifying glass around the
subsampled image and see a full-resolution image section in another
window.  This would seem inherently easy to do in a class, such that
you could just set a switch to tell whether to use the subsampled
image or the real thing.  A method could give back a local blowup
given a location in the subsample and the desired size.

On another note, I, too, got unsubscribed against my will, and was out
of action for at least 2 months.  I missed most of the discussion
regarding my previous postings on a wrappable numeric library.  I
don't know how this happened but perhaps it might be worth looking
into, given that it's happened to many of us.

--jh--