Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Hi,

I solve numerically an ODE system which depends on 25 parameters.
I want to know the maximum value of the time at which a specific event is triggered, when these parameters vary (independently the one of the other) within a 25 dimensional hyperbox.

To solve this maximization problem, which I assume is local1, I would like to use NLPSolve

The attached zip (I use Mac OSX) contains:

  • a file that gives a full description of the problem (the original ".pages" file and its export as pdf),
  • an m file wich contains the solution procedure plus a few other variables needed to solve the problem,
  • the mw file which contains:
    • the reading of the m file,
    • the procedure (OBJ) which returns the trigerring time,
    • many attemps to find its maximum value using NLPSolve.

None of my attempts at using NLPSolve gave me the expected answer

Could you help me to fix this?

Thanks in advance

mw_and_m_files.zip

1: Initializing a local method (see the explanation file) with different points gave me different optimizers but all of them led to rather close values of the objective function. Thus the problem is either global instead of local, or convergence might not be achieved for all the initialization points (but keep in mind that I'm not interested in the location of the minimizer(s) but in the maximum value of if the time when the event is triggered).

When I was drawing a plane graph, I found that the labels  of vertices were not displayed  and some edges even overlap when drawing because they were too close due to embedding.

restart:
with(GraphTheory):
g:=ConvertGraph("GsaCB{");
DrawPlanar(g,stylesheet=[vertexborder=false,vertexpadding=5,edgecolor = maroon,vertexcolor=gray,edgethickness=3])

So I thought that  option  Interactive  can adjust the position manually, but  at the same time I found that the style of  edges, such as the color and thickness, etc., is lost.  How to handle it? Is this a bug?

restart:
with(GraphTheory):
g:=ConvertGraph("GsaCB{");
DrawPlanar(g,stylesheet=[vertexborder=false,vertexpadding=5,edgecolor = maroon,vertexcolor=gray,edgethickness=3],layout=interactive)

I am trying to simplify a large expression using simplify(), but it takes too long and I eventually run out of processing power after a few days. Is there any way I could get similar results with an alternative function?

Any help is appreciated.

 

 

Maple 2021.1 screen shot: property box too small to select properties

how it should look like

How do I get it back to normal?

Thank you

I'm getting a strange error today when trying to save a file on the network. Rebootet machine, no change.

Any hints?

Hello!

I am trying to integrate this function numerically from x=0... 1, by using int and evalf(Int) but maple cannot handle it. Is there another kind of numerical integration?

(2*x-1)^2*(2*n+(5*(2*x-1))*(x-1))*(2*n-5+5*x)*ln(1-(5*(1-x))*x/n)/((1-x)^2*(-2*n-(15*(1-x))*x))

Are there another kind of procedures to do numerical integration?

 

 

Hi!

I have created a procedure for the so-called "Chaos Game" for the generation of Fractals. The file is the following:

Fractals_ChaosGame.mw

On the other hand, for a given day set D:={(x0,y0,(x1,y1),...., (xN,yN)}, for simplicity we assume D is contained in [0,1]x[0,1], one can to construct an "Iterated Functions System" such that its attractor set contains the set D. A detailed exposition of this topic can be found in the famous Barnsley's book "Fractals Everywhere". Also, in the following paper (sections 2.5 and 4-A):

https://arxiv.org/pdf/2102.09855.pdf

I have tried to implement in Maple 17 a procedure to create such Iterated Function System:

IFF_v2.mw

But, I feel that there is something wrong...After plot (with the Chaos Game procedure) a lot of points of the Iterated Functions System (i.e., an approximation of its attractor set), I have a "set of points", instead of a figure similar to a curve (which I feel that must be the correct).

Please, Somebody can have a look to the attached files?

Many thanks in advance for your comments.

On virtually any webpage is a mixture of images and text. I can go to the page, select all contents, copy the contents into an Excel spreadsheet, save the spreadsheet file and then use the ExcelTools:-Import function to read the file into a DataFrame. At that point, I can work with the data.   All the text on the webpage, even if it is embedded in some HTML command, is copied as text into the spreadsheet which eventually can be read as text by Maple.

My quesiton is, what is the method for me to bypass Excel and import the webpage directly into Maple, striped of the HTML code? Can someone point me to an example? (The only examples I have seen use the Sockets package, but I thought this mode has been superceded with Import.)

Can you use the Dirac function in different coordinate systems?

Dear all

I have a second order PDE, i used pdesolve but no solution obtained, why?

pdsolve_pde.mw

thanks

 

 

Bellissima used kripky modules to find the labels for one and two generators. the number of these labels increses to a very large number as we add another level. Can maple help count these lables? and how?

We know that it is easier to get all  non-isomorphic graph on n verteices in maple. 

with(GraphTheory):
g:=[NonIsomorphicGraphs(8, output = graphs, outputform = graph)]:
nops(g)

 

But it's not very convenient for planar graphs except for select, especially for special planar graphs (for example,  all triangulations on 12 verices) that have slightly higher number of vertices. In fact, maple has relatively few options for generating special graphs. 

Fortunately, Plantri can do  that at a high rate of speed. Here's the web version of Plantri (http://combos.org/plantri ), so we can enjoy it. More interestingly, I see that Maple has a license to use Nauty  and plantri. https://de.maplesoft.com/support/help/maple/view.aspx?path=License%2fNauty

But I don't know if Maple has any interface functions to use nauty or plantri , and that would be great!

PS: 

  1. Nauty can generate all unlabelled simple graphs on a given number of vertices with various additional properties.
  2. plantri is a program for generation of certain types of planar graph.

 

Hi,

I have had trouble with a  .mw worksheet..which I will attach.(I am using Maple 2021)..This is second time it got corrupted..I used the

"CompleteMiniCourseComputerAlgebraPhysics" and copy parts to worksheets so I can work the problems and I do 

Alot of markups and highlighting as well as add coments a copy as Text from help on certain commands..

I read some other posts that discuss corrupt file thats use XML I think in the worksheet....I checked this in the area I was working and did not find anything (I completed about half of the course saving as I went and had no problems)....so any guidance would be appreciated..

ThanksMyMinitCourseComputerAlgebraForPhysicsPart2_-_Copy_-_Copy.zipMyMinitCourseComputerAlgebraForPhysicsPart2_-_Copy_-_Copy.zip

Frank McFee

How I have used maple 2018, 2019 and 2020. I am now trying to switch to 2021, however the resolution is irritating. The resoluion in the palettes tab is bad and is especially bad for the "popup suggestion window" when you press escape on like "sum" or "e". I have tried searching on google to fix it but have not been able to find any help. Using windows 10

The pictures attached shows the resolution problem.

I know it is a small issue, but it annoys me a lot. So any suggestions to what I could do?

Maybe I am missing something here. Maybe it's just a new feature?

I have just installed Maple 2021 on Mac.

A simple sheet, using simplify-simplify to get units right.

Sometimes Maple doesn't update result when pressing Enter.

Sometimes Maple doesn't give any result when pressing Enter.

First everything ok:

Then I change a to 5 m. Pressing Enter on all three lines gives:

The value of A is not updated.

If I then delete the 'simplify 9 m^2' and presses Enter on the line with A:=a*b, there is no output?

Pressing Enter on blue line, no output.

 

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