ecterrab

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19 years, 154 days

MaplePrimes Activity


These are replies submitted by ecterrab

Hi
Thanks for the kind comments. It was a difficult decision, but everything has an end, even an apparently "never-ending" career that has already been long, more successful, and more fun than I could have imagined. 

As Andrew's post says, I will continue to work on existing Maple code, including the Physics package - my first computational project at University - and the Maplesoft Physics Updates, though on a 'have time' basis.

In connection, some people were curious about the cherished projects Andrew mentioned, which I intend to continue developing on a 'have time' basis. They are the most important ones I developed at Maplesoft along all these years. Some symbolic packages, some numerical, lots of technical writing, some looking more like courseware. This is a list of these Maplesoft projects, including the names of co-authors and students that worked on them together, cut from the CV

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@scallopedpancake 
Your attachment has problems. Try downloading it and you see it doesn't work.

What is needed: a Maple worksheet, termination ".mw" illustrating your problem. Important: The description in the mw needs to tell what you expected and what you received that does not match that - or else what you expected and have no idea of how to get it. And yes, a short example is simpler to follow and so understand than a long one. Thanks.

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@segfault 

 

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft


Download Relative_sign_of_the_Lagrangian.mw

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@Jamie128 
Yes. It is possible to use Physics:-LagranteEquations to get field equations for gravity by using a (modified gravity) Lagrangian. Check the attached version of the help page of LagrangeEquations - it is reproducible by installing the latest Physics Updates (open Maple and input Physics:-Version(latest)).

Download LagrangeEquations_PhysicsUpdates.mw

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@nm 

A dot release is not a version ahead. You need to be clear about this. Only a few bug fixes enter the dot releases, fixes considered critical for one reason or another. The Physics Updates contain significantly more fixes than that, also developments (entirely absent from dot releases). So no, you do not have Maple 2 versions ahead.

About your comment regarding "... fixes for very old bugs", what is what you consider old? The fixes mentioned in this conversation are for bugs all of them newer than March 2024, this year.

Your statement about odetest hanging does not change what I said before. In that "odetest hangs" post of yours, first, you show it does not hang. Then you show that if you first interrupt computations using timelimit and assumptions, next a hang occurrs. Perhaps you are unaware that interrupting a computation in that way leaves fragments of results in caches. That does not usually generate problems, but sometimes it does. In particular, your problem in that post involves is, assume and coulditbe. As you probably remember, in some cases, is and coulditbe interrupt with an error the first time, then they do not. These nuances can produce problems as the one you mentioned, not a problem in odetest.

By the way, if you want to know what hangs, Maple offers the tracelast instruction - I already mentioned this to you before. That allows you to post the actual problem, which in your example is not a problem in odetest; if it were, then it would have hanged the first time. It is also not a problem in the Maplesoft Physics Updates, even if its presence uncovers a problem not noticed before - that sometimes happens, you know that too.

Then the way you wrote this post I am commenting, it does look like "why are the fixes found in the Physics Updates not present when I remove the Physics Updates?" For me, that indicates you are not clear about how this works. Maybe you were not clear of what a dot release is.

Anyway, I can see you expecting even more from the software; I don't share your expectation, the comments aim at explaining that.

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

The Maplesoft Physics Updates is a project that aims at bringing to the current Maple release fixes that are present in the version under development, as well as new developments in the areas of Physics, Differential Equations and Mathematical Functions. Somehow, your posts these days, @nm , either indicate you are not clear about that or perhaps you are trying to say something else?

In this one above, you say that a version of the Maplesoft Physics Updates fixed a reported problem (and, you know, also other problems not reported in Mapleprimes). Well, if you remove the Maplesoft Physics Updates, the problems that it fixes are not fixed anymore. I find that natural—what were you expecting?

I also mentioned other times that installing the Physics Updates may reveal a problem that was not apparent without it. Yes, that can happen—report the case. Depending on the problem, it may get fixed in one of the next versions of the Updates, or you may need to wait until the next release because, sometimes, other problems are seen as a higher priority. All this is known.

In summary, you have two options: install this Maplesoft Physics Updates package and have all those fixes and developments "in advance", or wait for them until the next Maple dot or full release (for Maple 2024, that would be next year).

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@Hullzie16 
Nice reply. Attached are a few comments intercalated in your worksheet that may be of interest. Physics is an environment with a myriad of simplifications for the input. They are not necessary but make entering things easier.

Tensor_Respond_(comments).mw

Best!
Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

This ODE system is solvable with the existing dsolve. But there is a problem in simplify subroutines. Before calling dsolve, input debug(`simplify/RootOf`, statements = false, depth = 1) and you see, at the end, the line that causes `simplify/RootOf` to interrupt with the Error message you saw. It shouldn't happen. I will see to include a fix for this in the next or so version of Maplesoft Physics Updates for Maple 2024, and write again here.

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@mehran rajabi 
In that case you can use PDEtools:-dcoeffs. What confused me and I imagine others is that in your question you said "[Given the equation] ... I want to calculate separately, c1,c2,c3,c4,c5" (in a computer algebra context, that has the meaning of performing some calculation) while, actually, you do not want to calculate anything, only extract the coefficients.

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

Hi @Carl Love, there are various, perhaps more like "many", things about the ODE and PDE code, the FunctionAdvisor, conversion network for math funcs, Physics ... that, while documented, the details are so many that end up buried, not noticed. The syntax you refer is explained in ?dsolve,system; scan for 'ranking', it appears almost on top of the page and also is explained in its own subsection, "The unknowns of the problem and rankings".

My impression of this thread is that the question was not properly formulated, or I may have understood it wrongly ... - I was in doubt. Mainly: my interpretation of the question is that this was about solving a system with f(x) and 5 c(x) "functions"whose derivatives are equal to 0, and the solution desired involved "f as a function of the c, and the c as functions of themselves at most", and that is what this ranking represents.

So, if I am correct, what was missing was a more precise description of what was intended. After that, the formulation followed naturally (for whoever knows the functionality available in 'ranking' details).

Best

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@nm 
Thank you. I added as a PS the worksheet containing the tracelast output, which is what allowed for reproducing the problem and fix it. And thanks to @aroche for his quick fix. The fix is already uploaded in the latest Maplesoft Physics Updates for Maple 2024, so to activate the fix, as usual, open Maple and input Physics:-Version(latest).

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

@nm 

Generally speaking, the more extensive is your post, the most unreadable and time-consuming. I suggest you to try to make your reports more compact. By the way, I work with GUI. Always try GUI first. If I cannot reproduce I move into 1D Math input, then TTY.

Now on the issue: there is a bug in the subroutines of `simplify/common/factors`. I passed the problem to the person who wrote the routine, I suppose we will have a fix probably by the end of tomorrow or Friday. Regarding your comments about whether you display or not things ... I don't know. The bug - restricted to the input to the mentioned routine, however, is reproducible no matter what you display.

Best

Thanks Austin, for the so quick fix; it is uploaded now within the Maplesoft Physics Updates v.1793. To install: open Maple and enter Physics:-Version(latest)

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

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