## Error, when trying to remove a task......

Hello people :)

As the captian says, im trying to remove an old task i've made.
But i get this:

Error in Get, invalid object [_XML_reply_data_get("reference" =
"_Maplets_reference_12","parameter" =
"#xa6","tning"))]

And i have no idea what it is, but it won't erase my task :'D

Have a great weekend you all
Best regards Lucas :)

## 2019.1 Help freezes whole computer...

A few seconds after calling up Help starts zucking araound and the whole computer then freezes. Ctrl-Alt-Delete doesn't work, hard reset required. Very funny. Am I alone?

## How to get all n nodes(n<=15) Non-isomorphic  conn...

I'd like to get all at most 15 vertices Non-isomorphic  connected  bipartite graphs. One way is to use the function NonIsomorphicGraphs(k, output = graphs, outputform = graph, restrictto = connected).

with(GraphTheory):

k:=8; s1:=[NonIsomorphicGraphs(k,restrictto = connected,output=graphs,outputform=graph)]: bipartitegraph:=select[flatten](x->IsBipartite(x)=true, s1): nops(bipartitegraph);
But when k=9, it is slow, I doubted that the code

By Checking out the encyclopedia，http://oeis.org/A033995 , we knew the following number of bipartite graphs datas of , at most 14, they are not many（the datas contain  no-connected conditions)

awesome.

Ps： I know  in SageMath  we can get all bipartite graphs quikly even though n>=10  by  using the

for g in graphs.nauty_geng('-c -b 10 -g'):

But I hope it can be realized in Maple.

Thanks!

## Probllem with member() and table()...

1. The member() function doesn't find the value in a table if that value is associated with the key (aka index)  '0'
2. Doesn't seem to matter if the table is created explicitly (ie by calling table()) or implicitly (ie by simple indexed assignment)
3. member() doesn't seem to have the same issue with a zero-based Array()
4. I'm pretty sure that this is a bug, but I'd like some opinions before I report it
5. This behaviour has been around for a while: same thing happens all the way back to Maple 18. (I can't check anything earlier)

Check the ouput of member(10,t1) in the attached

 > restart:
 > interface(version);
 (1)
 > # # Explicit table creation: same thing # happens if table is created "implicitly" #   t1:=table([0=10, 1=12]);   member(10,t1);   member(12,t1);
 (2)
 > # # Zero-based Array #   A:=Array(0..1, [10, 12]);   member(10,A);   member(12,A);
 (3)
 >

## Are these bugs of maple 2019? ...

Hello people in mapleprimes,
I have a question.

I use maple2019 with mac os 10.14.6.

\$ sw_vers
ProductName:	Mac OS X
ProductVersion:	10.14.6
BuildVersion:	18G95

With maple2019, errors appears.

> kernelopts(version);
Maple 2019.1, APPLE UNIVERSAL OSX, Jun 6 2019, Build ID 1403154

> assume(a>-1,b>0);
Originally a, renamed a~:
is assumed to be: FAIL

> assume(tau<1,tau>0,s<1,s>0):
> a_e1:=tau*s*(1+tau)<tau*s+tau+s-1:
> b_e2:=expand(lhs(a_e1)-rhs(a_e1))<0:
>  b_e3:=collect(b_e2,s,factor):
> solve(b_e2,s) assuming tau<1;
Error, (in assuming) when calling 'property/ConvertProperty'. Received: 'FAIL
is an invalid property'

On the other hand, with maple2018, they do not.

> kernelopts(version);
Maple 2018.2, APPLE UNIVERSAL OSX, Nov 16 2018, Build ID 1362973

> assume(a>-1,b>0);
Originally a, renamed a~:
is assumed to be: RealRange(Open(-1),1)

> assume(tau<1,tau>0,s<1,s>0):
> a_e1:=tau*s*(1+tau)<tau*s+tau+s-1:
> b_e2:=expand(lhs(a_e1)-rhs(a_e1))<0:
> b_e3:=collect(b_e2,s,factor):
> solve(b_e2,s) assuming tau<1;
1
[{-------- < s~}]
1 + tau~

Are errors due to some bugs in maple2019 when being used with mac os 10.14.6?

Take care.

taro

## How to do I make it work properly?...

Hi everybody!

Quick question for you guys. I have access to Maple 2019 on my main computer and Maple 2018 on a remote Desktop (but I don't want to use because it's super slow and bad (normal rdp stuff)). The problem I have is for the same document, same line, same instruction, Maple 2019 on my computer is failling to do it correctly (unable to do the matrix correctly) and in the Remote Maple 2018 it's doing it just fine. I really don't understand. If someone can give me a little help it would be highly apreciated!

Maple 2018 (what it's supposed to do):

Maple 2019 (what it is not suppose to do):

## How to evaluate a table within a package module....

Glyph2.maple

The above link is a maple workbook containing the package Glyph2 together with the install script and two worksheets illustrating the difficulty I am having with the code in the procedure assignaltbasis (near the end of the code in Glyph2.mpl).

The problematic code is shown standalone is basisdemo worksheet, but reproduced below for reference. Interestingly, even though the table should be evaluated in a seq command, outside the module it works without eval. Inside the module evaluation does not make any difference.

indxs := [1, 2, 3, 4];
altbasis := [seq(seq(e[i[]], i = combinat:-choose(indxs, 2*k)), k = 1 .. 2)];
gen := table([seq(op(gen[i]) = bivec[i], i = 1 .. nops(gen))]);
exprs := [seq(exteriorp(seq(gen[op(2*i - 1 .. 2*i, b)], i = 1 .. nops(b)/2)), b = altbasis)];

The worksheet Basischangedemo shows how the exported procedure “assignaltbasis” is used in the module and the error that results if a bivector basis is used. From experimentation I have found that the error results because “assignaltbasis” passes the table name to the procedure “exteriorp” instead of the bivectors that should have resulted from evaluation of the table. Including the eval command within the seq procedure does not make any difference to the result. I am unclear whether this is a problem with evaluation of the table or a problem that results from namespace conflict.

I have a further namespace problem with the local variables, AltRoot, AltToStd, and StdToAlt which store the results from assignaltbasis.  If I declare these variables as exports, I get an error message “attempt to assign to a protected variable”. Therefore I added an exported procedure “ShowAltBasis” to display the results.  As you can see, this procedure produces the fully-qualified names of each blade making the result difficult to read. I would prefer to get rid of the “Glyph2:-” qualification.

The waters are muddied even further because the other worksheet, “basisdemo”, contains the core code extracted from assignaltbasis showing that the code using the table actually works (outside the module). From this I conclude that a namespace conflict exists within the module, preventing the table from fully evaluating.

My understanding is that within the module local and exported names are more or less equivalent, so I am puzzled why local and exported names in assignaltbasis are so problematic.

I would appreciate any advice about these issues. Clearly my understanding of maple’s namespaces is incomplete.

## Show ODE solution step by step...

I'm using dsolve command to solve a differential equation. Using infolevel to 3 will tell me the classification of said DE. However, how can I see the step by step solution? I'm using Maple as a study tool so I do solve manually a DE then I'd like to compare my answer with Maple's. How can I acomplish this? Thanks in advance.

## Students discount...

Please may I know if you can offer ma student's discount ob the seleted version.

Thank you.

Fred.

## When i type sqrt(25), i get 1.81847767202745*10^(-...

Yeah, i have tried evalf[10](sqrt(25)).
How can i get a simple number as answer? I'm loving the software but i just wished i could type in:
int(sin(x), x = 0 .. pi)
and get 2 instead of (2.739493386*10^(-116) + (2.739493386*10^(-116))*I)*pi.
Also, when i type evalf[50](pi), i wish to get all the 50 digits, but i just get \pi :/.

## Severe basic bug in Maple 2019.1 in Document Mode?...

Dear Maple users

Some students have come to us to report, that something doesn't seem to work properly in Maple 2019.1 in Document Mode. And they seem to be right: writing an passive math formula by using Shift+F5 (the formula is gray, not blue), then using F5 to get out of that Math field and back into Text Mode. Using the Enter key to go to the next line: It doesn't work! The cursor stays in the same line. This behavior is new in Maple 2019. It worked properly in Maple 2018 and earlier. I assume it is not the intention?

I know it can easily be dealt with by making a new Paragraph by using the shortcut Ctrl+Shift+J. I call the assumed bug 'severe' though, because it will severely delay the workflow for many students. They are used to deliver a document mixed with formulas (active or passive) and text.

NB! I have tested it on several computers (Mac and Windows), and it doesn't work on any of them.

Regards,

Erik V.

## Trouble converting units directly from evaluation ...

I've recently changed to maple 2019, from the 2016 version as my license for that product had expired.
However I find it really frustrating that often upon evaluating an expression I can't convert the units.

For instance I had a calculation that evaluated to:

2.114163508*10^7 [kg/s^2]

When I try to directly replace the units within maple to instead be [J/m^2] I recieve the following error message:

"Error, (in  Units:-TestDimensions) 'op(3, i) does not  evaluate to module"

There is no explanation for this error when I try to look it up. However if I once again manually write the answer:
2.114163508*10^7 [kg/s^2] and use the replace units function.
No problem.
I find this quite annoying and frustrating and I hope you can help.

Best regards

Anders Alexander Wagenblast

## how does Maple decide which is simpler expression?...

This is may be a philosophical question. But sometimes Maple suprises me when telling it to "simplify" expression. As in this example.

 > expr:=1/(y^3+1)^(2/3);

 > int(expr,y)

 > simplify(%)

 >

For me, the original result is "simpler". (Not only smaller leaf count, but it has one special function, vs. two: Legendre and Gamma). But may be Maple considers hypergeom always more "complex" than any other?

That is why I use simplify(expr,size) because I am scared of simplify without any option, as I have little idea how it decides which is simpler.

Any thoughts from the experts on how Maple decided to simplify something when no option is used? What kinds of rules it uses to decide how to transform the expression?

Maple 2019.1

## Strange behavior of sqrt function....

I'm new to Maple.

My problem is that if I input the command sqrt(3.0), for example, I get this strange result:

1.81847767202745*10^(-58) + (7.53238114626421*10^(-59))*I

The results is the same, no matter the argument of sqrt.

Also, when using ln, I get this:

-265.745524189222 + 0.785398163397448*I

Again, no matter the argument of ln, the result is the same.

What is happening?

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