Re: Wolfram Research QA process defect: Bug in Mathematica 6 - Integrate - 68 (Sqrt, invalid value) - BUG THE LONG LIVER: 1996-2008 (!)


[...]
Daniel,
My guess is that the developer(s) of Macsyma, Reduce, ScratchPad, and
JAM would all be horrified (as well as amused?) at the amount of errors
in the current crop of systems. Just a guess: the vast increase in
computer speed has been so seductive that developers have raced ahead of
their ability to properly code and check out that code. That's the
charitable view. The alternative viewpoint is that commercialism is too
seductive.

Misses the mark. The errors in question are in areas that do not have
fully algorithmic treatment. Naturally there were no such bugs back
when nobody tried to make such things work.

One of the systems you mention is not, at this time, defunct.
I rather suspect its developers would be delighted to have
reached the level of relative quality that some of us can boast.


As To Matlab: It sure is a CAS whether it specifically does elliptic, or
any other particular type of manipulation. It can take an s-plane
diagram/description of a system and generate control algorithms that are
flyable. In some senses, doing this well enough to achieve FAA approval
is a much harder problem that Wolfram or other similar vendors are
tackling. In other senses, it isn't. However, producing flight-worthy
software from mathematical input is quite an achievement. It's one of
the major accomplishments of your industry so don't knock it.

I do not knowck the capabilities of Matlab. I simply point out
that, your remarks to the contrary, it does not do "computer
algebra".


As to "announcing a bug in definite integration." That's hopeless. If
definite integration doesn't work in general, that product version
should be delayed and not shipped.

That is one opinion. It's not one I share. When polynomial
gcds are incorrect, then shipment delays are advisable. A
certain level of bugginess in definite integration is
unavoidable. Whether you, or others, choose to accept
that situation is of course up to you. I'm just spelling
out what the situation is. I've yet to see a credible
explanation as to why I might be wrong.


The announcements I have in mind
should be MUCH more specific so a reasonably knowledgeable user (not
necessarily a world beater) knows which parts of the system are
suspicious. Such announcements are, of course, the responsibility of the
vendors. If you believe otherwise, then ask your masters to distribute
the source code. (Didn't think you would.)

There comes a time in many failing threads where someone
uses a phrase like that last to score points. One advantage,
to me, is that it serves as my exit cue.


As to "the sky is falling." I spent many years trying to convince some
large engineering concerns that their future would be well served by
using CAS, particularly those enhanced with serious domain knowledge
(such as Matlab) and auto-code capabilities, to design and build complex
artifacts. Most of the response I got was expressed disdain at the state
of the art and maintenance of the necessary tools.

Well, Matlab, Mathematica, and other programs, are ever more
getting used in engineering and other industrial settings. I
suppoose you can chalk up a belated victory here.


Lastly, I think it is inappropriate for you to ask VB to determine
whether two errors that he discovers are from the same source or
different sources. As I assume you know, two expressions that look very
similar may be handled by radically different code inside the CAS, e.g.,
replacing a "*" by a "/" might change an integration from "elementary"
to not and the CAS will follow different paths.

-- Jeff Barnett- Hide quoted text -

Scintillating. Though it hardly gets at the heart of
definite integration, let alone the redundency of
what is appearing on sci.math.symbolic.

Over and out.

Daniel Lichtblau
Wolfram Research

.

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