## Webscrapping: Importing text in HTML file / webpag...

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 (The only examples I have seen use the Sockets package, but I thought this mode has been superceded with Import.)

## Dirac delta function...

Can you use the Dirac function in different coordinate systems?

## How to use the ExpandSteps correctly and wisely....

I have some algebraic expression which I want to expand.

I used the ExpandSteps command to show me the steps, but I guess I used it incorrectly.

Attached below the file with the commands.

It should be expanded to -\Delta*\sin^2(\theta), but I want maple to show me the steps.

## How to plot a specific implicitly defined solution...

Worksheet_1.mw

Dear members,

first of all, this is my first question so please excuse me if it is posted in a bad way. Anyway, here is my problem:

I am trying to plot a function V(k,i(k)) over the positive real numbers k>0 where i=i(k) is the implicitly defined solution to

chi(i)-w(k)=0.

Both maps chi(i) and w(k) are relatively simple and well-defined. However, depending on k, two solutions to chi(i)-w(k)=0 coexist, call them i^1(k) and i^2(k). Hence, I want to have two plots:

V(k,i^1(k)) over k as well as V(k,i^2(k)) over k.

Below is my code:

The output is

which corresponds to only one of the solutions. How can I visualize the other solution?

Thank you and best regards,

Paul

## How to remove line number from showstat()？...

We know that the  showstat()  function can provide some available source codes, but it also provides line numbers.  I need to delete one by one to use it, which is not efficient when I want to copy and modify codes. Is there any way to directly remove those line numbers.

for exampe:

showstat(PlaneDual);

## Does Maple have a interface of plantri to generat...

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.

I have a procedure where M:=[m2,m3,m4...] and I  assign the m's values from list L:=[0.1,2....]
The procedure will only run once. Rerunning will not reassign the m's.

What is the correct way to do this?

Assign_in_proc.mw

## Physics package update ... problem...

Latest updates of Physics package (problem start with version cca 1020) is not announced at Maple cloud user window (see attacehd snapshot). The same problem occur on Windows and Linux platform!

## How to deal with Corrupt Maple worksheets?...

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..

Frank McFee

## IsThere a Problem with the Typreseeting in Maple 2...

I have attached some screenshots of the display in Maple 2021 which seem to appear after Maple has been up for an extended period of time (seemingly 3+ hours). The odd characters are not present when the tabs are initially opened, and the problem disappears for awhile after a restart.  Generally, I have not noticed a similar problem in Maple 2020.  However, the corruption of the output affects not only user created worksheets, but also help pages and examples opened from help as can be seen in the image below.

FYI I am using M2021 on an HP Omen gaming laptop that is several years old, but has been updated (drivers and windows)  as they become available.

## Bad resolution for maple 2021...

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?

## No update result pressing enter...

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.

## Documentation for ChangeCoordinates?...

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?

## Trying to collect tdeg. coefficient of multivariat...

I have a polynomial in c & d.  I wish to extract the coefficients of lets say 3rd order i.e c^3+c^2d+c d^2+d^3.

The polynomials can be of 2,3,4.. variables.

coeffs(14*c^4 + 84*c^3*d + 180*c^2*d^2 + 165*c*d^3 + 55*d^4 + 5*c^3 + 21*c^2*d + 28*c*d^2 + 12*d^3 + 2*c^2 + 5*c*d + 3*d^2 + c + d + 1, [c, d], 'l');
14, 84, 180, 165, 55, 5, 21, 28, 12, 2, 5, 3, 1, 1, 1

l[1];
4
c

l[2];
3
c  d

l;
4   3     2  2     3   4   3     2     2   3   2        2
c , c  d, c  d , c d , d , c , d c , c d , d , c , d c, d , c, d,

1

## Quantum Mechanics for Chemistry

by: Maple 2021

Quantum Mechanics for Chemistry

J. F. Ogilvie

This interactive electronic textbook, freely available from the Maple Application Centre [https://www.maplesoft.com/applications/view.aspx?SID=154768] in the form of three Maple worksheets comprises three extensive chapters, on model systems, atoms and molecules in turn.  As quantum mechanics is neither a chemical theory nor even a physical theory but a collection of methods, numbering at least thirteen, or algorithms, for calculations on systems of an atomic scale, it is appropriate that computer software combining both strong arithmetical and symbolic capabilities, i.e. Maple, be applied to implement this material.  The book includes calculations involving five of the known methods, and provides many examples and exercises for a reader to enhance understanding of the principles and practice. For the first and third chapters, a readable text as .pdf is also provided but the extent of the second chapter precludes this possibility.

The objective of this textbook is to demonstrate how the principles of the varied methods become implemented in practical calculations. The chapter on model systems includes treatments of several oscillators that might serve as prototypical of features of diatomic molecules.  The chapter on atoms includes the most extensive treatment available on solutions of Schroedinger's equation for the hydrogen atom, in all four systems of coordinates in which the variables are separable, and also in momentum space.  The chapter on molecules includes an introduction to transparent quantum-chemical calculations, which enables a reader to understand each stage of a calculation on a simple atomic or molecular system leading to a self-consistent field and even to Moeller-Plesset perturbation theory of second order and application of density functionals, which can provide an excellent basis for a subsequent use of opaque numerical programs for calculation of molecular structures and properties.

This textbook contains, with permission, contributions from several eminent chemists, mathematicians and physicists, acknowledged in the particular locations, that complement the explanatory descriptive text as a profound introduction to quantum mechanics in a context of chemical education.

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