I found a case where PDEtools:-Solve fail and solve works. I do not understand why. 

Is this a bug or what is going on? I thought they should give same result.

Download why_PDEtools_Solve_fail_august_14_2024.mw

I am very confused about this result. 

I call the result of odetest the residual. Which should be zero or simplifies to zero if dsolve solution is correct.

Now, if I do     odetest(solution,ode), I get residual which simplifies to zero. OK. But doing odetest(solution,[ode,IC]) now gives output for the ode residual (first entry) completely different than the first case and which can't be simplified to zero any more. 

odetest also says the solution satisfies the IC, since the second entry of the residual is zero.     

So we have case where the solution satisfies the ODE itself and also satisfies the IC. But when calling odetest with both the ode and the IC, now it says the solution does not satisfiy the ode.

How could this be? What Am I overlooking here? Should not the ode residual remain the same in both calls?

Download odetest_problem_august_14_2024.mw

Hello

I need to use the Ritt algorithm to find the characteristic sets of a set of differential equations. In the past, it seems there was a Maple package by D. Wang available through Maple Applications, but this no longer appears to be the case. I managed to download an old set of files from the author’s site, dated February 1996, which is a Maple V3 package. The instructions in the Readme file mention that using the provided Makefile, an m-file containing all the functions will be created, which can then be loaded into Maple. Unfortunately, running make -f Makefile did not create anything, so I am wondering if I could get some assistance on how to convert this package to something compatible with the latest Maple releases.

The source (txt) files are structured as follows:

Example: 

1) Comments
2) Definition of the User functions - something like

 

dcharsets[dcharset] := proc() `charsets/d_charset`(args) end:

dcharsets[dmcharset] := proc() `charsets/d_mcharset`(args) end:

dcharsets[dcs] := proc() `charsets/d_charser`(args) end:

dcharsets[dmcs] := proc() `charsets/d_mcs`(args) end:

dcharsets[dics] := proc() `charsets/d_ics`(args) end:

and

read `charsets.m`:

# set of non-zero remainders of d-polys in ps wrt d-ascending set as
#       user level function
`charsets/d_remset` :=

subs(`charsets/class`=`charsets/d_class`,
     `charsets/remseta`=`charsets/d_remseta`,
     `charsets/premas`=`charsets/d_premas`,op(`charsets/remset`)):

and lots of Maple procedures - Example below

 

`charsets/d_charset` := proc(ps,lst,medset)

....

end:

the source file ends with the following lines.

read dhelp;
save `dcharsets.m`:
quit

Many thanks

Note: Before posting this question here, I tried to contact the author but received no response.

Hi,
 i observe this error as if a sum() was used instead of a add() in dsolve

> assume(g > 0): dsolve({diff(r(t), t$2) + g * t * r(t), r(0) = r0, D(r)(0) = r1},  r(t));
Error, (in dsolve) unsupported type of index, _a

any help or advice, please ?

Sincerely.

I noticed sometimes Maple dsolve solves an ode using a method different than what odeadvisor says it is.

In this example ode, advisor said it is separable. But when solving it, dsolve actually solved it as dAlembert.

Why is that? Should not these be the same?

I also noticed Maple does not verify the solution of the ode when asked to solve it as separable, which is what the advisor says. But it does verify the solution using dAlembert.

So in this example, should not advisor have said this ode is dAlembert and not separable then?

Download why_different_method_used_august_13_2024.mw

I use a procedure called Isee  to print to screen procedures from my packages.

However if the procedure is overloaded it Isee doesn't print it. Is there a way around this.
I have inserted screen shots to show the outputs for the package.

Download 2024-08-12_print_overloaded_procedure.mw

I was looking at the application center about attractors and found the Rossler attractor app that illustrates the Rossler Attractor with animations, as you can see below. But when I try to run it on my laptop  the two last plots remain empty. Why is this happening?

Download rossler_attractor.mws

How to get Li(x) to display as result of int(1/ln(x),x) in Maple instead of -Ei(1,-ln(x))? 

I'd like to match result of Maple with another software I use and it is also simpler to look at

int(1/ln(x),x)

Now gives

             -Ei(1,-ln(x))

How to make it show  Li(x) instead?

The Maple help page for Li is this

And the other software Li help page is this

I tried simplify in Maple but it does not do anything. How to get Li(x) in Maple for int(1/ln(x),x);  instead of -Ei(1, -ln(y)) ?

Note that 

diff(Li(x),x)

Gives 1/ln(x) so Li(x) is the correct antiderivative.

Here is also the wiki page

I know that Maple's result is correct, I am just asking about the form it is shown. Since Maple has Li(x) function, why not use it for this result?

Maple 2024.1

Download Attractors.mw

Hi everyone...

How can I remove the warning (Warning, (in anonymous procedure created in Typesetting:-FI) `m` is implicitly declared local
) from this for command in Maple 2024? I know the warning can be ignored but I want to remove it anyway.

for k from 1 to 4 do
    A[k] := Matrix(k, k, (i, j) -> local m; ifelse(i + j < k + 2, add(Y[i - m + j - 1]*binomial(i - 1, m)*(-1)^m, m = 0 .. i - 1), 0));
end do

tnx...

I do not think I ever saw this warning messages from dsolve. This is _Clairaut first order ode. When adding the option singsol=all in the dsolve call, Maple replies with 

I do not have earlier version of Maple to try as my C: drive died and lost all my Maple's installed versions. I need to to try to install older version of Maple sometime and check.

Is this new warning and why does it show? Is this suppose to happen? 

Download strange_warning_message_from_dsolve.mw

I also noticed these warning messages show up only the first time dsolve is called on this ode.

Calling it again right after, using the same command, the warning messages no longer show up, which is  even more strange.

I am plotting phase plot of two first order ode's.

I noticed when added +t to one ode, the plot generated losses all the slope fields. Any one knows why and if this is just limitation of DEplot or if there is a way to workaround it. 

THis worksheet has first example showing expected output, then second example where +t was added first ode. Now same code generates plot will all the slope field gone.

Download strange_DEplot.mw

update

if someone is interested, I found Maple has builtin function to check if system of ode's is autonomous or not. So changed my code to check first. Here is how to check:

Download strange_DEplot_V2.mw

I found that  DynamicSystems package uses global variable called s

THis makes zero design sense. Why would a package use a global variable that could have been used by a user? 

What is the correct way to prevent this warning message from showing up, as I have no control over what variable can be used in global space.  I also tried to declare s as local to the function that is using the package, but that did not help. Only way was to remove variable from global space before.

Any suggestions?  And why DynamicSystems is even using global symbols in first place?

Download dynamic_systems_uses_gloabl_s.mw

For display of plot axes labels, I prefer to use the Typesseting in place so that diff(y(x),x) display as y'(x) (takes less space and looks better also).

It does that in the worksheet. But when using diff(y(x),x) as the Y axis label, the plot still shows diff(y(x),x) and not y'(x).

Is there a way to make plot and DEtools:-DEplot  use the Typesetting in place?   What is the point of using Typesetting if plots generated do not use it?
 

Download labels_for_plot_do_not_use_typesetting_maple_2024.mw

Notice the label on Y axis above. I'd like that to display as y'(x) as it is in the worksheet.

I noticed very serious problem in Maple 2024.1

This is new windows 10  22H2  installation. With Maple 2024.1. I've only seen this using Maple and no other windows applications. I have 2 monitors and NVIDIA GeForce RTX 3060 graphics card.

What happens is that sometimes (may be 2-3 times each day), Maple frontend gets all mangled up. I could not figure what causes it. it could be when I move the window from one terminal to the other. sometimes it happens when I open a debugger window.

Only way to fix this is to close all of Maple and start it again. 

Here is a movie. I use only worksheets. I have 3-4 open at the time.  When I move the mouse over the worksheet it keeps shuffling and duplicating as you see.

Just wondering if anyone seen anything like this and what can cause it. Again, it is only Maple that shows this problem, no other windows application does this. Have 128 GB Ram and PC is only 2 years old.

This is the very first time I see this in Maple and used Maple for long time and on this same PC before and had two terminals also before all the time. I have no idea what causes it.

Could it be Java problem in Maple 2024.1 ?