ecterrab

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15 years, 79 days

MaplePrimes Activity


These are replies submitted by ecterrab

@JonMcLoone 

... hmm I wonder how is that my name ecterrab appears in your reply, Jon. In my reply to you in that Mapleprimes post of 2015, I gave my opinion that both systems have their strengths. Then elaborated about Maple's capabilities in mathematical functions (FunctionAdvisor), mentioned DifferentialAlgebra, DifferentialGeometry, Differential Equations and Physics, areas where I think Maple has better performance, or in the case of Physics, there is nothing really similar in Mathematica to compare with. I work on these projects and feel comfortable talking about them. But  I don't write Maple's advertisements - but for perhaps some sentences related to these areas just mentioned only - not the topics of this thread.

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

@rlopez 

Hi Robert,

That option exists, alias. Further below Pascal mentioned it in the context of Latex, but it is of course valid outside that context too. For example, something in your mapleini file like 

alias(seq(c[k]=_C||k,k=1..10));

would make 1) the _Cn invisible forever (you basically never use equations of order > 10, and if it where the case, make it 20) and 2) keep all the library working properly; many library routines scan for _Cn, they will all find it even when they look like c[n].

On the other hand, making an option like in LinearAlgebra:-LeastSquare has the obstacle that all the library routines that scan for _Cn will not find it anymore, because now something else would be in use (and no alias around to help to find the right object).

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

@nm 

In view of your goal being Latex related, Pascal's idea seems to me simplicity at its best. I like that. You can complement his suggestion to cover your concern about N as follows:

> N := sol -> `PDEtools/max_C`(`PDEtools/_C`(sol)) - 1:      # the answer to your question

> sol:=dsolve(diff(x(t),t$4) = x(t));
> alias(seq(c[k] = _C||k, k = 1..N(sol)));              # Pascal's suggestion
                                      c[1], c[2], c[3], c[4]


Besides, suppose you know the differential order of the equations you are handling, and you know they are all of order 5 or less. Well, then N = 5 suffices. In the _Cn, the maximum value of n is the differential order.

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

@Carl Love 

You are 100% right. Sometimes my brain does literal translations without thinking ... I fixed the pages now; not differential to non-differential in: PDEtools/ConsistencyTest, PDEtools/DeterminingPDE, PDEtools/Infinitesimals, PDEtools/InvariantSolutions, PDEtools/ReducedForm, PDEtools/SimilaritySolutions and PDEtools/SymmetryTest.

7x Thanks :)

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

@nm 

In Maple, there is type algebraic. It is not a good idea to use that word in the context of Maple help pages. Not differential is understandable but non-differential is also OK - @Carl Love, does it read better? If so I have no problem in changing it.

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

@nm 

There is a different processing of the PDE determining system for the infinitesimals (DEtools:-odepde, or PDEtools:-DeterminingPDE). The symgen routines are more oriented to getting one pair of infinitesimals - that is enough to solve an ODE - while those in PDEtools are oriented to get all existing pairs of infinitesimals - not just one to solve an DE. In doing so, they can end up facing an almost untractable problem from the point of view of differential elimination (packages DifferentialAlgebra, DEtools:-rifsimp, or DifferentialThomas). Try PDEtools:-casesplit(DEtools:-odepde(ode, [f(x), x*g(y)])) and you see the hang. There is nothing wrong with that: the underlying differential elimination problem is - in practice, for the existent differential elimination software - untractable. Perhaps adding some option with the meaning of "get something for me, not just everything" ... I'd need to think about.

PS: next answer only in a day or more - am busy with other stuff.

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

@nm 

So it wasn't \mathbf after all. OK. Regarding \boldsymbol: this Tex StackChange thread tells me it was obsolete in 2017.

Your discovery and comment, however, is always welcome and useful, don't get me wrong please. And in this case took me to discover there is \boldmath (not \mathbf) which requires no additional package and accomplishes bold & italics in the presence of \mathit.

I will do some more tests here. If everything passes to my satisfaction I will change textbf & textit by boldmath & mathit and put the change in the next version of the Maplesoft Physics Updates so that everybody can try it.

PS (I) after posting: tried. There are several problems, it is not a solution. Being that in this particular case textbf & textit works perfectly fine, this becomes a sort of irrelevant thing at this point, I will keep it as is until I see a solution that works as well, without having to load yet another package, and without having to add to the complexity of the code, in a case like this one, with no gain in functionality.

PS (II) after posting: did more experimentation, and taking everything into account \boldsymbol does look like the winner. So in the Maplesoft Physics Updates v.793 there is only \mathit and only \boldsymbol, to respectively get italicized and bold, and spaces between words are preserved.

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

 

@nm 

Please note, you are not answering my question. I said: when we need italicized and bold, none of bf, textb or mathbf combined with mathit produce it. Up to what I know, only textbf & textit does it. Do you know an alternative?

So if you have a way to produce italicized and bold at the same time, please say it. Otherwise the code remains with textbf & textit when it needs to address that particular requirement until we discover something better.

For an example, easy: open www.overleaf.com, where you can try for free, fast and with ease, and input

\begin{equation}
\textbf{\textit{This\,is\,text}}
\end{equation}


And you will see italicized and bold. Try now changing texit by mathit and feel free to change textbf for whatever you want, click on Recompile to see the output. If you get italicized and bold, please post here what combination of mathit with whatever you used, and I will think about again.

The example, anyway, is not as artificial as you may think, consider this real case scenario:

> EllipticK(z);  # with Typesetting = extended and SpecialFunctionRules ON, it is a K in bold & italics
                          EllipticK(z)

> Physics:-Latex(%);
\textbf{\textit{K}}\left(z \right)

 

For the notational conventions used to display this or other mathematical functions that also use bold and italicized, see the NIST - Digital Library of Mathematical Functions which is the main reference nowadays.

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

@Carl Love 

So I would be the crippler? What a choice of words yours. There are better words in the dictionary to describe your thoughts about things that you don't understand the rationale behind or that you differ in opinion.

This is typical output seen in Maple worksheets, wether using Physics:-CompactDisplay or PDEtools:-Declare

That is seen for instance in the translation to latex via File -> Export -> Latex of a worksheet being produced as a paper for a Journal (mind you: you don't have the javas under development to see equation labels). 

Removing the blank spaces between words in the above would not be correct, I think. Besides that, two comments:

  • In v.792 I changed from textit to mathit as much as possible, resolving the issue as mentioned in my first reply: use mathit with some extra space in place of those blanks automatically removed by mathit. So at this point you will see mathit, most of the time, and these special cases of blanks not removed.
  • There is one exception I couldn't find an alternative: when you need bold and italicized. Any combination of bf, mathbf or textbf with mathit does not render bold and italicized. Only textbf & textit does. Are there other options?

By the way, in v.792 of the Maplesoft Physics Updates, Physics:-Latex is a package and you can see the Usexxx variables that you can assign to get different kinds of output; among them there is UseImaginaryUnit, that you can assign to a name to be used instead of the value of interface(imaginaryunit) when that is what you prefer. With time, or when the package is ready (say fresh from the oven in a week from today - not meaning free of things to adjust as usually happens with new stuff), these are to be handled by a command Latex:-Settings,

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

@nm 

Respecting the user's choice of imaginaryunit is relevant. Independent of that, try with(Physics:-Latex) and you will see all the Usexxx variables that you can assign to produce different kinds of output. Among them there is Latex:-UseImaginaryUnit. If you set it, that is what will be used, not the value set via interface(imaginaryunit). If you change UseImaginaryUnit in the middle of a worksheet after having used Latex, at this point you will need to Latex:-Forget() to clear caches. When the package is ready this is supposed to be handled by a Latex:-Settings command, that manage all the Usexxx variables.

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

@nm 

It works fine in v.789, and thanks for all the feedback. 

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

@michalkvasnicka 

The problem is not in the Maplesoft Physics Updates. The problem is in the installation of MapleCloud packages in the toolbox/2020 directory in the Windows platform. Regarding your question, yes, the Physics Updates - I am referring to the package, not the installer - is tested before being uploaded.

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

@michalkvasnicka 

Unfortunately, the problem seen in the Windows platform when trying to install the Maplesoft Physics Updates is, generally speaking, something I cannot fix. It is not a Physics package problem, not a Maple library problem. It is a problem with the mechanism to install packages that affect only the Windows OS (probably the one mostly used, I know). I am saying "generally speaking" because past experiences have shown that sometimes it is possible to work around a problem like this with patching libraries. But I also do not use Windows and so have no direct way to reproduce the problem in order to see if a library workaround could work.

I heard, however, that people at Maplesoft taking care of this installer problem are now able to reproduce it, so as other people, I am also looking forward for their fix.

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

@nm 
Sorry for that, a mistake at night. It is corrected in v.789.

By the way, suppose you install the "latest" Maplesoft Physics Updates, that you can do via Physics:-Version(latest); and you see something went wrong with latest. You can always rewind to any previous version. For example, if latest = 786 you can input restart; Physics:-Version(785); restart; and you are back to the previous version.

Independent of all that: the Latex:-UseColor := false is relevant only when there is some color to be put, for instance in Latex(Int(f(x), x)) the integral sign and differentiatial are to be displayed in gray, and are translated to tex including the instruction to use that color, that in some context is unnecessary or undesired.

PS: I haven't seen your latex_issue_4.mw, where did you post it?

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

@nm 
I see. But that is a different issue (your original one was about changing Typesetting settings - by the way: please post different problems in different posts to avoid this situation).

This problem you mention now is not related to Latex. It is instead a subtle problem in the internal routines of solve when `assuming` uses Physics:-Assume, more modern code than the old assumewith more functionality, and a setting that is necessary for other packages to work properly (Physics, Differential Geometry, VectorCalculus, LieAlgebrasOfVectorFields, ...).

While different problem you are mentioning now, not-related-to-Physics-or-Latex, is fixed,

  • In the Updates v.781, assuming starts using Physics:-Assume only after you enter "with" Physics or use Physics Export that requires the full setup of Physics. Not when you use Physics:-Latex.
  • Or, if you use a previous v.xxx, after loading Physics you can enter Physics:-Setup(assuminguseAsume = false); and that makes `assuming` use the old assume program again, and then for this example you posted solve doesn't have a problem. Unfortunately, doing that can produce some unexpected results since the (very) old assume program redefines global variables in a way that makes several packages fail. Though again this is not related to Physics:-Latex, something that involves no mathematics whatsoever.

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

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