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JacquesC

Prof. Jacques Carette

2401 Reputation

17 Badges

20 years, 83 days
McMaster University
Professor or university staff
Hamilton, Ontario, Canada

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From a Maple perspective: I first started using it in 1985 (it was Maple 4.0, but I still have a Maple 3.3 manual!). Worked as a Maple tutor in 1987. Joined the company in 1991 as the sole GUI developer and wrote the first Windows version of Maple (for Windows 3.0). Founded the Math group in 1992. Worked remotely from France (still in Math, hosted by the ALGO project) from fall 1993 to summer 1996 where I did my PhD in complex dynamics in Orsay. Soon after I returned to Ontario, I became the Manager of the Math Group, which I grew from 2 people to 12 in 2.5 years. Got "promoted" into project management (for Maple 6, the last of the releases which allowed a lot of backward incompatibilities, aka the last time that design mistakes from the past were allowed to be fixed), and then moved on to an ill-fated web project (it was 1999 after all). After that, worked on coordinating the output from the (many!) research labs Maplesoft then worked with, as well as some Maple design and coding (inert form, the box model for Maplets, some aspects of MathML, context menus, a prototype compiler, and more), as well as some of the initial work on MapleNet. In 2002, an opportunity came up for a faculty position, which I took. After many years of being confronted with Maple weaknesses, I got a number of ideas of how I would go about 'doing better' -- but these ideas required a radical change of architecture, which I could not do within Maplesoft. I have been working on producing a 'better' system ever since.

MaplePrimes Activity


These are replies submitted by JacquesC

Probably a safe feature...

JacquesC 2401
December 18 2006
Thinking about it, that feature makes sense. It would be much too easy to (ab)use things if one could edit a front-page post after it has been promoted. While I am all for a free forum, that doesn't meant that the front page should be a free-for-all.

No longer on the front page?...

JacquesC 2401
December 18 2006
I had mis-classified my post, so I changed that. Now my post is no longer on the front page. Is this a known ``feature'' of Drupal?

Closed form (from the paper)...

JacquesC 2401
December 18 2006
0 0
Pi*n*2^(-n)*sum( (-1)^r*(n-2*r)^(n-1)/r!/(n-r)!, r=0..ceil(n/2)-1)

Closed form (from the paper)...

JacquesC 2401
December 18 2006
Pi*n*2^(-n)*sum( (-1)^r*(n-2*r)^(n-1)/r!/(n-r)!, r=0..ceil(n/2)-1)

Good catch...

JacquesC 2401
December 17 2006
For some reason, I rarely think of overloading/overriding Maple's internal routines to get around their quirks, even though Maple will so nicely allow me to do it. It's a dangerous game, but still a good technique.

re: colons...

JacquesC 2401
December 14 2006
0 0
Colons 'only' suppress output, yes, but in many places in the documentation it is (rightly!) pointed out that : and ; are equivalent. And this is true in Maple's native parser. So this is a bug in the post-modern parser; it is not too surprising that a second parser for a language as complex as Maple has such bugs; it will take a few years for it to settle to something usable. Is there someone at Maplesoft who scavenges all bug reports made on MaplePrimes and properly reports them? I have now seen quite a few reported here, and it would be rather sad if the developers did not get informed!

re: colons...

JacquesC 2401
December 14 2006
Colons 'only' suppress output, yes, but in many places in the documentation it is (rightly!) pointed out that : and ; are equivalent. And this is true in Maple's native parser. So this is a bug in the post-modern parser; it is not too surprising that a second parser for a language as complex as Maple has such bugs; it will take a few years for it to settle to something usable. Is there someone at Maplesoft who scavenges all bug reports made on MaplePrimes and properly reports them? I have now seen quite a few reported here, and it would be rather sad if the developers did not get informed!

Well known...

JacquesC 2401
December 13 2006
Not everything can be covered in basic undergraduate courses... The types of things you are ``discovering'' were (in part) already well-known to Euler. If you want a (ahem) modern introduction to this topic, I certainly recommend the book Divergent Series by G.H.Hardy. If you read French, then Lecons sur les series divergentes by Borel is well worth it.

Things to look at...

JacquesC 2401
December 12 2006
0 0
Certainly I would dig in to `simplify/hypergeom/args21` and `simplify/hypergeom/contig21`. Sometimes I have found that using gfun[holexprtodiffeq], then gfun[algebraicsubs], then dsolve or some of the commands in DEtools or Slode have worked for me. Once I get a nice series, I use that for the numerics. Buried in this paper seems to be a lot of relevant material, along with some interesting web-based work.

Things to look at...

JacquesC 2401
December 12 2006
Certainly I would dig in to `simplify/hypergeom/args21` and `simplify/hypergeom/contig21`. Sometimes I have found that using gfun[holexprtodiffeq], then gfun[algebraicsubs], then dsolve or some of the commands in DEtools or Slode have worked for me. Once I get a nice series, I use that for the numerics. Buried in this paper seems to be a lot of relevant material, along with some interesting web-based work.

dsolve/numeric options...

JacquesC 2401
December 12 2006
Take a good look at all the examples in ?dsolve/numeric, especially those that talk about listprocedure and output=array(). Also, if your input is in a list, the output will be in a list in the same order.

More details on the special case...

JacquesC 2401
December 07 2006
0 0
Can you be more specific about which case you are looking for? I could not guess for your original post. I am no expert on this topic, rather a hobbyist, but still, that might be sufficient.

More details on the special case...

JacquesC 2401
December 07 2006
Can you be more specific about which case you are looking for? I could not guess for your original post. I am no expert on this topic, rather a hobbyist, but still, that might be sufficient.

Faster?...

JacquesC 2401
December 06 2006
I really hate if-then-else that return booleans. So I really hope that r := proc(x) evalb(x::table) end: is faster!

Lambda Abstractor...

JacquesC 2401
December 06 2006
0 0
It is true that Maple's unapply is the same as Church's lambda abstraction operator. However, take a look at programming languages out there, at those languages that have first-class functions. You'll notice that very very few of them have something akin to Maple's unapply. LISP and Scheme have it. You can fake it in PHP (for example). Mathematica, MuPAD and their kin have it. In a lot of languages you can write inline lambdas, but what you can't do is to compute an expression and then abstract it. This is one of the very few features of Computer Algebra languages which cannot be found in other mainstream languages. And it is quite fundamental.
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