Maple 2021 Questions and Posts

These are Posts and Questions associated with the product, Maple 2021

I used to have this kind of code without problem:

myModule := module()
    option package;
    export myFunc;
    # local i;
    myFunc := proc()
        [seq(i, i in 1..10)]
    end proc;
end module;

But after upgrading to the latest version of Maple 2021, I get a warning

Warning, (in myModule:-myFunc) `i` is implicitly declared local |myModule.mpl:5|

I have to uncomment the local i declaration for the warning to go away. Has the behavior of seq changed in Maple 2021?

In mathematica, CommunityGraphPlot attempts to draw the vertices grouped into communities. 

g = Graph[{1 \[UndirectedEdge] 2, 2 \[UndirectedEdge] 3, 
   3 \[UndirectedEdge] 4, 1 \[UndirectedEdge] 4, 
   1 \[UndirectedEdge] 5, 5 \[UndirectedEdge] 6, 
   5 \[UndirectedEdge] 7, 7 \[UndirectedEdge] 8, 
   8 \[UndirectedEdge] 9, 7 \[UndirectedEdge] 9}, 
  VertexLabels -> "Name"];
ged = {{6, 7, 8, 9}, {5}, {1, 2, 3, 4}};# Gallai-Edmonds decomposition
CommunityGraphPlot[
 HighlightGraph[g, FindIndependentEdgeSet[g], 
  GraphHighlightStyle -> "Thick"], 
 Thread[Labeled[ged, {"D(g)", "A(g)", "C(g)"}]], PlotTheme -> "Web"]

This function is very useful, for example, if I get a partition of vertices, such as the gallai-Edmonds decomposition below, I use  CommunityGraphPlot to easily see the overall layout of the graph. I don't know if Maple has a corresponding function.

PS: The Gallai-Edmonds decomposition of a graph g is the partition {D(g),A(g),C(g)} of its vertices, where D(g) consists of every vertex v for which there exists a maximum matching of g that misses v, A(g) consists of every vertex v that is not in D(g) but neighbors some vertex in D(g) and C(g) consists of all remaining vertices.

Hello,

I encounter the same error for upgrading the physics package

which was never solved for Maple 2020 !

See the screenshot.

This is again a problem of permission.

Best

Hi I have experienced another Maple 2021 error with those of my students who Maple 2021 Mac edition. 

Lets say their have saved a .mw on their main drive and tries to open the file from inside Maple. Maple gives an error like "file cannot be opened - please try to another". This also happens when trying to open the file from outside Maple. 

This never happens on the Windows version. So any idea what could be causing this ?

I have the following expression.

Ps = (x - 600)(15000 + 400*(y - 4000)/2000 + 15000*0.40*(850 - x)/100) - y

Maple will evaluate this to:

Ps = (x - 600)(15000 + 400*(y - 4000)/2000 + 15000*0.40*(850 - x)/100) - y

Screenshot:

Plotting these two in 2D on Desmos to demonstrate: https://www.desmos.com/calculator/tvp4rbzxzp

These two are not the same expression. Is Maple broken or am I doing something wrong?

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)

 

 

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

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?

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.

 

Reviewing the help Physics Examples worksheet Section 1, subsection 5 a transformation between cartesion and spherical coordinates is defined using the command ChangeCoordinates from the Physics[Vectors] package. This command is described briefly as follows in the Updates, Maple 2015, Physics page:

"New command: ChangeCoordinates, to rewrite an algebraic expression, using Cartesian, cylindrical, and spherical coordinates, an expression that involves these coordinates, either a scalar expression, or vectorial one but then not changing the orthonormal basis."

However, when I use the link to the ChangeCoordinates help page, the link simply loops back to the Updates, Maple 2015, Physics page.  Is there a specific help page for the ChangeCoordinates command?

Maple 2021.1/Windows 10.

When entering 2d expressions into the bottom line of a worksheet, i.e. at the bottom of the window, I can't see the underscores used to indicate bracketing.

A workaround is to use ^J to get another input prompt at the bottom of the window.

Is there some way to get a bigger margin at the bottom of the window?

Cheers,

Steve.

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