@wingho

I assume that with "literature" you mean the Maple help system.

I had a look at pdsolve documentation. I do not see a pdsolve option that reports of solver settings (including the type of solver). This would be useful when it comes to modifying default parameters and solvers.

I also tried infolevel[pdsolve] := 5, but this does not give more information (this works for dsolve).

Have you consulted: ?pdsolve,numeric,education/p>

This seems to offer more options (solvers and parameters) to solve your pde.

About the physical problem:

Can I assume that u(x,0) is equivalent to the compression of a rod at t=0?

If so, the solutions make quite sense to me. The relaxation propagates with the speed of sound. It reminds me of a falling slinky.

Remarks: The initial compression with 25% is quite high which could require modeling that accounts for large deflections (non-linear effects).

@dharr 

Compared to my original post, your puzzle can be reproduced. It is probably a regression.

Unfortuneately we cannot probe what the user interface sends to the kernel and what the kernel receives.

Edit: I seems that MaplePrimes has different challenges interpreting 2D-Math. Better open the attached worksheet

Download ditto_2-D_Math.mw

@acer

I edited my reply.

I don't think it's a bug. But I think I did not understand what you were demonstrating with the uneval example with respect to equation labels. I could not make use of it.

I am only guessing that the user interface attaches equation labels to output from the kernel and replaces equations labels with whatever is attached before sending this to the kernel. If I may say so.

Why the parameter modifier ::uneval is not making form the argument sol[1] a 'sol[1]' is something I do not understand since I do not know the evaluation rules when a procedure is called. This is probably descirbed somewhere in the documentation. The only difference between the arguments is that sol[1] is a name assigned to an expression and the second argument is an "anonymous" expression. In this example c is not evaluated

c:=2;
f := proc(x::uneval) x^2 end proc:
f(c)
                             c := 2

                                2
                               c 

So why is sol[1] replaced by the expression to which sol[1] is assinged to?

@acer

Maybe I am wrong. I though that

sends only an indexed name for sol[1] and the whole output of equation label (2) with the index 1 to the kernel. If I copy the command and paste it here (or in 1D-Math input) I get exactly that.

ExpressionTools:-Compare(sol[1], (y(x) = RootOf(-Int(1/(2*cos(_a) + RootOf(-Int(1/(2*cos(_a) + _Z)^(1/2), _a = 0 .. y__IC) + x__IC + c__2))^(1/2), _a = 0 .. _Z) + x + c__2), y(x) = RootOf(Int(1/(2*cos(_a) + RootOf(Int(1/(2*cos(_a) + _Z)^(1/2), _a = 0 .. y__IC) + x__IC + c__2))^(1/2), _a = 0 .. _Z) + x + c__2))[1])

When the kernel evaluates the above, the second argument is taken as is and first
edit: the first argument 
is taken from the kernels memory wihtout any further evaluation.

Can the communication between the kernel and the UI be recorded?

@acer 

Thank you.

My takeway finding is that the kernel did not know the output I was refering to.

When names are used, those surprises won't happen. By habit I use euqation labels. This comes from text book style documenation where variable names and assignemt operators could distract or confuse readers that do not know Maple.

@pchin

Types and properties are another area where the Maple language offers more than traditional programming languages, but also requires a deeper understanding. 
This is less essential for beginners than eval but key to understand Maple. Here is an example that I could not work out myself

https://www.mapleprimes.com/questions/242362-Difference-Between-Non0-And-NonZero-

I sometimes (when reading comments or replies here on MaplePrimes) I have the impressions that some users assume that fundamental mathematical concepts are known.

I never really have been well educated at school in math (or I did not pay attention). At university math in itself was less important than (mathematical) problem solving. Since then I enlarge my mathematical knowledge and skillset where needed. Only recently (about 5 years ago) I discovered Maple's help system as a resource/reference to educate myself. The help system is hard stuff in the beginning since it requires a certain level of understanding Maple "parlance" but, as far as I can see, it is very consistent and accurate.

In the light of sloppy AI replies I think that good manmade content is still of value. If AI could refer to trustworthy content (including videos and example worksheets) this would be a big step. Right now it can give a good introduction into a subject but lacks accuracy and is often not consistent with Maples help system.

It is also possible to make `&D;`atomic and move it to the favorites but this prints `D` in the input when inserted from the favorites.

Download Italic_D_in_the_favorites.mw

The videos are good.

One of the things I had to learn with Maple was the concept of evaluation. Without knowing the meaning (in the Maple language context) the correct interpretation of many Maple help pages is not possible.  For computer scientists evaluation is probably something natural to talk about. Appart from Maple I never have to use the word evaluation. For most programming task the knowledge of evaluation is not needed (although it happens all the time under the hood); assignment is more important.

In your last video, you demonstrate that a previously assinged name leads to an error in a subsequent statement. This is only because Maples parser is not smart enough to understand the intention of the user.

Also "evaluation to a name" is something most users that have started programming with other languages do not know because ordinary languages do not use names the way Maple does. Such languages have variables where a value can be assinged to. Without an assignement such variables are useless which is not the case in Maple.

For these reasons I think a video about evaluation would make sense.

RootOf is annother powerful "particularity" of Maple also worth explaing.

@acer

Comments are always welcome. I think I got your point, which does not mean that I will always express myself correctly in the future.

As the term function, the terms object and operator can have different meanings. Since computer science and math have so much in common it is challenging not to mix things up.

I still see the need to clarify a few details which are related but become more and more off the topic ()().

Thank you again for the clarifications.

@acer 

This explains one thing I noticed recently

Your clarification of `+` on its own is nothing more than a name (or the name of a function - I could have worked this out myself) now fits perfectly to eval (and "evaluation to a name") in the word evalapply. It also fits nicely to “functional programming” that applies functions in the first pair of parentheses to arguments in the second pair of parentheses.

What does not fit perfectly, IMO, is the use of terms in the examples/functionaloperators help page. It would make sense to rework this page and update with links to ?evalapply and ?function.

Prefix and infix variants of the same operation can make it more difficult to describe, interpret, and understand. That is a dilemma of a rich language. On the other hand, it's less fun when languages are reduced to a minimum. 

examples_functional_operators_comments.mw

operators_functional_commented.mw

@Carl Love 

I was not aware of evalapply. The help=page clarifies a lot (and is unusual since it explains in the Description section an example of the Example section).

The types in, for example, (`+` + `+`) are not all the same and make unambiguous processing possible - whatever the exact rules are.

Thank you for filling one of my gaps!

@dharr 

Converting to 1-D seems to remove hidden code that cannot be visualised by a Maple command.

I had this in other instances and sometimes only retyping or deleting of document blocks helps.

@aroche 

After installing Maple 2026.1 and uninstalling SupportTools I did


then I got the same crash on computer "A" and the package was not installed. 
I will do this on computer "B" when I find time and update here if computer "B" crashes as well.
If not let's make this a "cold case" unless we can relate this to any other strange behavior of the UI on computer "A".

This works now with the new release

@ianmccr 

This sounds more like what the user @nm experienced here. Maybe he can tell more.

If it is file related I would try to isolate the passages that cause the block. Simply delete pats of the document and try uploading again. 

@acer 

File replaced