Thomas Richard

Mr. Thomas Richard

1828 Reputation

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10 years, 102 days
Maplesoft Europe GmbH
Technical professional in industry or government
Aachen, Germany

MaplePrimes Activity


These are answers submitted by Thomas Richard

Have you tried increasing the interface variable screenwidth? It defaults to 79 in command line Maple.

Please consult our FAQs: https://desktopfaq.maplesoft.com/customer/en/portal/articles/2840902-maple-does-not-start

They have not only been restructured, but also extended, so that more situations (problems and solutions) are covered now.

Futhermore, for Windows 10 users who had installed the so-called Creators Update: that makes trouble with several applications including Maple. They can crash upon starting or saving files, at least on some systems. In that case, unrolling that update helps, or – if that is not an option – deleting the so-called God-Mode by removing the

    C:\Users\%USERNAME%\Desktop\GodMode.{ED7BA470-8E54-465E-825C-99712043E01C}

folder.

The PDEtools package has the proper command for this task: DeterminingPDE. However, your jet-like notation will need to be adjusted a bit to be processed by diff_table.

I'm not an export on that topic, but this should get you started to do further symmetry investigations:

with(PDEtools):
declare(Q(x,t),R(x,t)): # optional
q := diff_table(Q(x,t)):
r := diff_table(R(x,t)):
pde1 := q[t] = alpha[3](t)*(q[x,x,x]-6*q[]*r[]*q[x])+alpha[2](t)*(2*q[]^2*r[]-q[x,x])+alpha[1](t)*q[x]-alpha[0](t)*q[];
pde2 := r[t] = alpha[3](t)*(r[x,x,x]-6*q[]*r[]*r[x])+alpha[2](t)*(-2*q[]*r[]^2+r[x,x])+alpha[1](t)*r[x]-alpha[0](t)*r[];
sys := [pde1,pde2]:
detsys := DeterminingPDE(sys);

As you can see, I renamed your original functions to uppercase Q and R...

Your first input line is most probably a result of some copy&paste error. Simply replace it by

with(simplex):

 

I'm not sure whether that can be achieved in Maple 2016, but Maple 2017 introduced a new option 'typesetdot' that helps here. Quoting from the Typesetting:-Settings help page:

typesetdot = true or false
Specifies whether dot notation is used in the typesetting of derivatives of univariate functions in the dot variable (see dot above). This setting is false by default and can be set to true only if the usedot setting is also true.

And here's its application to your example:

restart:

with(Typesetting):

Settings(typesetdot=true):

Suppress(x(t)):

diff(x(t),t);

diff(x(t), t)

(1)

with(VectorCalculus):

Suppress(y(t)):

<diff(x(t),t),diff(y(t),t)>;

_rtable[18446744074058402862]

(2)

 


Download new_typesetdot_2017.mw

We also have a typesetprime setting now.

Yes, the name v seems to be treated incorrectly by internals of NLPSolve. As a workaround, insert

local v:

before defining that function.

Thanks for bringing this to our attention!

I have never encountered that error message, but it sounds as if it's a candidate for the new Initialization Diagnostics App in MapleSim 2017; see https://www.maplesoft.com/products/maplesim/new/

Furthermore, It's a good idea to check "Solver Diagnostics" under "Simulation Settings". This can help with pinpointing the problematic part of a model.

Ad hoc, I have no idea how to handle this (unusual) IC, but your PDE is of first order, so the method of characteristic strips is always worth a try (see ?charstrip for the background). It boils down to:

PDE := (y-u(x,y))*diff(u(x,y),x)+(u(x,y)-x)*diff(u(x,y),y) = x-y;
infolevel[pdsolve] := 3:
ans := pdsolve(PDE,HINT=strip);
pdetest(ans,PDE);

Maple hints that this may not be the most general solution (another new feature, see Help > What's New > Partial Differential Equations). Incidentally, this equation is solved in Maple 2016 already.

For MapleSim models, please visit our Model Gallery and enter "inverted pendulum" or similar terms into the search box. One hit is https://www.maplesoft.com/products/maplesim/ModelGallery/detail.aspx?id=27.

For books on MapleSim, check out https://www.maplesoft.com/books/search.aspx?keyword=MapleSim
Ideally, you're fluent in German. :-)

I'm not sure where the problem is arising: text editor, file format, or some limitation of the (rather simplistic) read command.

If you write the procedure in a Maple worksheet and then use

save test,"test.mpl";

the read call will work as expected.

However, storing procedures in external text files should no longer be necessary since Maple introduced the Code Editor a few years ago.

If you still prefer separate files, but want to keep them in one location with the worksheet(s), please take a look at the Workbook format that was introduced in Maple 2016.

There is an issue with the Intel graphics driver not being fully compatible with an update of Windows. After closing the window a handful of times, it will stop appearing and Maple will start like normal.


We have pointed out this in a support e-mail to you in late July already. ;-)

Please check the help page by entering ?plottools:-getdata in Maple. It's very easy to extract the data points from that structure. Exporting can then be done via the generic Export command, or (more specifically) ExcelTools:-Export and ExportMatrix (which supports various MATLAB formats).

Quoting from ?Groebner,MonomialOrders:

'matrix'(M,V) is a matrix order, where V is a list of variables and M is a list of lists of rational weights.

So you simply have to rewrite your definition of M into: M:=[[1,0],[0,1]];

The LA shortcut notation you had used is for creating Matrices, and equivalent to assigning M:=Matrix([[1,0],[0,1]]);

Please see the help page by entering ?convert,D in Maple, or visit the online help page.

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