Maple 2020 Questions and Posts

These are Posts and Questions associated with the product, Maple 2020

I am creating Maple figures that are being used to create camera-ready figures in Adobe Illustrator. The graphic artist doing the Adobe Illustrator has asked me if there is a way to have the text information in the figure (tickmarks, axis labels, ...) saved as text and not created as an image?

I know that other EPS files have text stored this way, but it appears Maple does not do this. I can't find any documentation about this. Does anybody have any knowledge or experience about this?

Thanks in advance,

Doug

I want to do the substitution f(t) - ff(t) = epsilon for any variable t in Maple:

 

expand(myerror);
    2 f(x - 2 h)   f(x)   3 f(x + 3 h)   2 ff(x - 2 h)   ff(x)
  - ------------ - ---- + ------------ + ------------- + -----
        15 h       6 h        10 h           15 h         6 h

       3 ff(x + 3 h)
     - -------------
           10 h     


NULL;
myfunc := t -> f(t) - ff(t) = epsilon;
 myfunc := proc (t) options operator, arrow, function_assign;

    f(t)-ff(t) = epsilon end proc


algsubs(myfunc(t), myerror);
          2               1        3            
        - -- f(x - 2 h) - - f(x) + -- f(x + 3 h)
          15              6        10           
        ----------------------------------------
                           h                    

               2                1         3             
             - -- ff(x - 2 h) - - ff(x) + -- ff(x + 3 h)
               15               6         10            
           - -------------------------------------------
                                  h                     


NULL;
subs(f(-h*n + x) = 1, ff(-h*n + x) = 0, f(x) = 1, ff(x) = 0, f(h*m + x) = 1, ff(h*m + x) = 0, myerror)*epsilon;
                           4 epsilon
                           ---------
                             15 h   

 

This happens each time I run a long loop.  (2,500 iterations, which takes about 3 hrs to complete)

Maple always hangs (it does not time out on odetest() ). But my question is not about this (as this is something I have to deal with for long time now and mentioned it before many times. May be one day Maplesoft will fix this). 

But I noticed this also.  When Maple hangs, (and it always hangs at least once during this loop), I then click on the button "interrupt the current operation". This does stop the hangs.

Next I do a restart and starts the loop from the loop counter where it hanged in order to continue.  

But It still hangs at that same iteration. I repeate this again, and it still hangs.

Now I close Maple altogether, start Maple again, open same worksheet, and repeat from the same iteration again from where it was at before, now it does not hang.

This tells me that restart and "interrupt the current operation" do not clean everything as expected. Else why only restarting Maple makes it work?

It means mserver.exe (separate process from the frontend) still is caching something related, and that is why it hangs at that iteration.

I can reproduce this each time I run the whole loop from the start.

I can't make a minimal example, since I have no idea where it hangs and why. And it is related to running a long loop.

I just know it hangs when doing odetest() with timeout which never timeout, and it seems random at what iteration it decides to hang.

But my question is really basic here: Does mserver.exe keep any information about the earlier user session/worksheet even after restart ? help says that restarts clear internal memory of the kernel.

Isn't mserver.exe  the Maple kernel? If so, then what could explain that only restarting Maple clears the hang? I am just looking for ideas that could explain this.

This type of problem is the most annoying thing about Maple for me. 

Maple 2020.1 on windows 10.

 

Anyone maybe helps me with writing the maple code mentioned in the following pdf.

I want to know about the potential flow around 3D domain.

 

Doc1.pdf

Why is pdsolve's 'generalsolution' option giving the particular solution u(x, y) = 0 instead of the general solution u(x, y) = A sin(x) sin(2 y) + sin(2 x) sin(y) for the attached problem?

Problem.mw

So, here again, I'm still having this problem with Maple 2020 on Machbook OS 10.13.6 (all updates have been performed): Maple 2020 does not start. I see an icon appearing in the dock but it then disappears soon without showing anything like splash something. I reinstalled and restarted the copmuter several times, reactivated the software several times (always successful), and still I'm having the problem. I installed java and then it worked for one time, but after that the same problem happens and I'm still having this issue.

I went through steps suggestged in the help and arrived at JAVA reisntallation. What else can I try? 

Please help me. Thanks.

Hiro

 

 

Suddently Maple 2020 (on Macbook) stops launching... I reinstalled it and restarted a couple of times. 

Can someone give me some clues about what is causing this problem.

I really need it right now... 

Thanks,

Hiro

 

Hello,

I have a particular problem that I haven't managed to find the solution to by googling.

9/10 times that I open Maple 2020 I can't seem to open any of my saved documents. it opens the start tab, and I'm still able to open a new document or worksheet, but then when I try to change to text instead of math, it won't let me. I can type, but I can't press backspace or enter.

I have tried restarting and shutting down my computer, but every time I have to just force quit Maple because it won't respond half of the time and it won't quit normally.

I'm running the latest version of Maple and using macOS Catalina version 10.15.5.

I've asked about this 5 years ago

 

https://www.mapleprimes.com/questions/203628-Maple-2015-No-Longer-Autoscroll-As

And according to the reply there at the time, this is supposed to have been fixed in Maple 2015.1:

It appears that the scrolling issue has been fixed in the next version of Maple

But ever since then, whenever I use Maple, the worksheet do not auto-scroll as the program runs and prints outout to the screen. I have to keep using the mouse to move the bar down to see the latest prints.

Not only that, the bar itself (on the right side) shrinks in size as more outpout is printed.

It becomes smaller and smaller with time, and becomes very hard to grab it with the mouse since it become so thin.  Once all the output is deleted, the bar become long again.

So I think there is an option to enable autoscrolling somewhere.

But I am not able to find it. I looked at options, display, general and interface and see nothing there to turn it on.

Sometimes I get the feeling that the folks at Maplesoft do not use Maple interface the way we users use it, becuase this is such a basic interface problem and any one who uses Maple interface for more than one day must see these problems all the time.

So how come these are still not fixed?  Here is a screen shot showing the bar on the right after long print out, and showing how it was before.

I use only worksheet mode, not document mode. On windows 10.

 

 

 

 

Error, (in Compiler:-Setup) unable to write to initialization file, C:\Program Files\Maple 2020\bin.X86_64_WINDOWS/launch.ini, possibly due to insufficient permissions
NULL;

when choose bat file

but i see sufficient permission

any w should i s

choose a particular compiler or even visual studio i have in my system

 

where can i find if anything else

Hello,

I try import a big Excel file with the first row as column labels for performing statistical etc.

I use this command :

data := Import(FileTools:-JoinPath(["d:", "directory", "subset2.xlsx"], platform = "windows"))

i need a dataframe for performing statistical with column label as first row, but i have this error :

Error, (in Import) invalid input: MatrixToDataFrame uses a 3rd argument, columns, which is missing

I can not understand what is this error...so, what i can do ?

Thanks, regards

The uploaded worksheet contains two examples of the use of VectorCalculus[VectorSpace]. The first example seems explicable but the second does not.

I have tried and failed to find a full, clear explanation of how a vector describing a simple vector, spacecurve, or surface in the default vector space is transformed to appear in a user defined vector space.

Can anyone direct me to such an explanation, so that I can understand Maple's processing within the uploaded worksheet and enable me to use this Maple feature to future advantage?

VectorSpaceTest.mw

Hello all,

I was hoping to get some general tips for tackling numeric integrals. As someone with little experience in the subject, I find myself overwhelemed by the many different integration methods. 

Experts, what are the first steps you take when trying to find a numeric solution to an integral? How might you zero-in on a particular integration method? What about tweaking error parametrs, etc.? Is there a general framework for approaching these problems, or is it all guesswork?

Thanks!

This worksheet shows an unexpected behavior of pdsolve().  It solves the heat equation on the interval (−1,1) but fails on the interval (0,1).  I see no technical reason for this happening — it's probably due to a little bug lurking somewhere.

restart;

kernelopts(version);

`Maple 2020.0, X86 64 LINUX, Mar 4 2020, Build ID 1455132`

Physics:-Version();

`The "Physics Updates" package is not installed`

Solve the heat equation on the interval -1 < x and x < 1 and

boundary conditions u(-1, t) = 0, u(1, t) = 0.

pde := diff(u(x,t),t) = diff(u(x,t),x,x);

diff(u(x, t), t) = diff(diff(u(x, t), x), x)

bc := u(-1,t)=0, u(1,t)=0;

u(-1, t) = 0, u(1, t) = 0

ic := u(x,0) = cos(Pi/2*x);

u(x, 0) = cos((1/2)*Pi*x)

pdsol := expand(pdsolve({pde,bc,ic}));

u(x, t) = cos((1/2)*Pi*x)*exp(-(1/4)*t*Pi^2)

That's good.  Apply pdetest to verify it:

pdetest(pdsol, [pde,bc,ic]);

[0, 0, 0, 0]

Now, solve the same problem on the interval 0 < x and x < 1 and

boundary condition u__x(0, t) = 0 and u(1, t) = 0.  It should be

evident that the solution remains the same as the one calculated

above, due to symmetry, and here is the verification:

bc_new := D[1](u)(0,t)=0, u(1,t)=0;

(D[1](u))(0, t) = 0, u(1, t) = 0

pdetest(pdsol, [pde,bc_new,ic]);

[0, 0, 0, 0]

But for some reason Maple's pdsolve fails to solve the PDE.  Actually

its response is somewhat erratic -- sometimes it returns nothing at all,

and sometimes it exits with an error message.

pdsolve({pde,bc_new,ic});

 

Download pdsolve-fails.mw

 

Hello

I wonder if someone on the list can give me some guidelines on how to use Grid:-Seq.

I have applied Grid:-Set and Grid:-Seq to one of my problems where parallelization is a possibility.   In this problem, I have a massive list of lists that needs to be processed in chunks and then a new list is returned.

What I've found so far:

1) Grid-Seq won't work if I use a procedure from a private module that calls local (or exported) functions of the same module.  Solution:  I need to use savelib (there is a bug in Grid:-Seq)

2) Grid-Seqs seems to be working fine up to a point where it simply stops.  For example:   Starting with 431895 sets, the procedure divides them into 864 sets of 500 elements (the last one does not usually contain 500 elements).  Then I use res:=Grid:-Seq['tasksize'=9](myFunction(newSets[i],...,....),i=1..864).   The messages sent out by Grid:-Seq are 

Seq: using tasksize=9; number of elements= 864, number of partitions = 96

......

Seq: done sending all partitions

Seq: received results from all nodes; collating results

After two hours running and using 36 cores, the result is available in res.  The next step is to use the results in res for another cycle of calculations.  1503462 sets = 3007 sets of 500 elements.  The messages sent out by Grid:Seq are 

Seq: using tasksize=9; number of elements= 3007, number of partitions = 335

......

Seq: done sending all partitions

The last message showed up on the screen after an hour. During the process, I saw the current tasks finishing and new ones starting.  However I could not see "Seq: received results from all nodes; collating result" after a day running.  I am using timelimit to be sure that all calculations will finish no matter what.  

I have checked the system information and found that: 1) all 72 cores are running but they are jumping from 0% to 100% (in the example that works I could see all of them in 100% solid), 2) Memory is at 156 GB (200 Gb is the limit) and no swap to disk.

I have also noticed:

  1. If I use Maple 2017, not even the first example works.
  2. tasksize=9 somehow helps with similar problems.  If the size is left for Maple to decide, it seems that the problem happens for sets of smaller size.
  3. On linux I had to use "kill -9" to remove maple from every single core. My impression is that Grid:-Seq does not clean up the processes after they finished.  
  4.  The problem seems to be on "results from all nodes; collating result".

 

I know that the explanation above in rather vague, but if someone has any clue or guidelines on how to solve this problem, please share it with me.

 

Many thanks

 

Ed

 

 

 

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