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JacquesC

Prof. Jacques Carette

2401 Reputation

17 Badges

20 years, 88 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.

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These are replies submitted by JacquesC

Classic?...

JacquesC 2401
November 08 2007
I was using classic when I did that. Perhaps that makes a difference?

substitution after assumption...

JacquesC 2401
November 08 2007
0 0
You have properly diagnosed the problem. What happens is that when you make an assumption (say on b), b is assigned a new value (in this case the escaped name b~). So you are trying to substitute for b in an expression that does not contain b, just b~. This is part of the fundamental design of assume! Try using eval (with 2 arguments) instead of subs.

substitution after assumption...

JacquesC 2401
November 08 2007
You have properly diagnosed the problem. What happens is that when you make an assumption (say on b), b is assigned a new value (in this case the escaped name b~). So you are trying to substitute for b in an expression that does not contain b, just b~. This is part of the fundamental design of assume! Try using eval (with 2 arguments) instead of subs.

Vector output...

JacquesC 2401
November 08 2007
0 0
First, I don't think it is piecewise that is the problem, it is a Vector embedded in a 'weird' context that (I believe) is the problem. To get that vector output, I cut&pasted the lprint-ed version of Maple's output, viz RTABLE(149559852,MATRIX([[t], [t^3], [0]]),Vector[column]) into <maple> brackets. And it worked...

Vector output...

JacquesC 2401
November 08 2007
First, I don't think it is piecewise that is the problem, it is a Vector embedded in a 'weird' context that (I believe) is the problem. To get that vector output, I cut&pasted the lprint-ed version of Maple's output, viz RTABLE(149559852,MATRIX([[t], [t^3], [0]]),Vector[column]) into <maple> brackets. And it worked...

Urgh...

JacquesC 2401
November 07 2007
0 0
Sigh. Just when you think you understand Maple, it throws you a curve. I guess one could use the type Or(linear([e1,e2,e3,e4,e5,e6,e7]), freeof([e1,e2,e3,e4,e5,e6,e7])) but that seems rather heavy-handed. Plus I hate the information duplication.

Urgh...

JacquesC 2401
November 07 2007
Sigh. Just when you think you understand Maple, it throws you a curve. I guess one could use the type Or(linear([e1,e2,e3,e4,e5,e6,e7]), freeof([e1,e2,e3,e4,e5,e6,e7])) but that seems rather heavy-handed. Plus I hate the information duplication.

Structured type...

JacquesC 2401
November 07 2007
0 0
But you could use the type linear([e1,e2,e3,e4,e5,e6,e7]), which is 'structured', and simpler still.

Structured type...

JacquesC 2401
November 07 2007
But you could use the type linear([e1,e2,e3,e4,e5,e6,e7]), which is 'structured', and simpler still.

CS = Computer Science...

JacquesC 2401
November 07 2007
So CSisms means issues that only matter from a computer science point-of-view. Loops are an operational concept which is forced upon us by sequential computers, not an issue that should matter when solving mathematical problems. Declaring your intent (that i is a positive integer) is a mathematical concern. Nicely, Maple (finally!) lets you do this. BTW i::And(integer, positive) is one way to say that.

Fixed...

JacquesC 2401
November 07 2007
0 0
Sorry, I was typing that too quickly -- I have fixed the post. r is indeed twice differentiable. The point was to show that the Normal was not even continuous. Serves me right for trying to do too many things at once.

Fixed...

JacquesC 2401
November 07 2007
Sorry, I was typing that too quickly -- I have fixed the post. r is indeed twice differentiable. The point was to show that the Normal was not even continuous. Serves me right for trying to do too many things at once.

Very strange...

JacquesC 2401
November 07 2007
0 0
I tried exactly that (so simple, it would be nice if that worked), and either got dsolve to go away forever, or produce an answer that was not a closed form. I will try again.

Very strange...

JacquesC 2401
November 07 2007
I tried exactly that (so simple, it would be nice if that worked), and either got dsolve to go away forever, or produce an answer that was not a closed form. I will try again.

Gorgeous!...

JacquesC 2401
November 07 2007
I am jealous. I wish I had thought of that.
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