## Bug in modp1(('Rem')(...))...

Hi there.

It seems like a bug in modp1(('Rem')(...)) with large polynomials with large coefficients.

bug_rem.mw

It needs the file polys.m there:

https://dropmefiles.com/9fATR

File polys.m too big for this forum so I used dropmefiles.

Polys.m contain two polynomials x and f_t with large degrees: degree(f_t) = m = 50021, degree(x) = 2*m - 2 = 100040 and large coefficients up to 2^N, where N = ceil(m / 2)+2 = 25013.

I just compute rem(x,f_t) mod 2^N.

As you can see in the first part of doc bug_rem.mw I decreased coefficients of polynomials by additional mod 2^N (with Embed function), where N = floor(N / 2) = 12506. WIth these decreased polynomials and decreased N modp1(('Rem')(...)) function works well and use maximum about 2.5 Gb of RAM.

But in the second part of doc bug_rem.mw with original polynomials and N = 25013 modp1(('Rem')(...)) use maximum about 3.5 Gb of RAM and crash with error:

Error, Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc

This is strange and looks like a bug considering that the test server has 48 Gb of RAM.

Is it a bug or modp1(('Rem')(...)) just need more than 48 Gb of RAM?

How many RAM it needs for this computation?

Thank you

## How to do a simple vector plot?...

I'm a new Maple user and wondering if anyone can explain how to plot vectors similar to this image.

I have seen examples of how to construct a plot with vectors (see example) but I do not want these bold arrows. A line with an arrowhead is clearer.

/Christer

## Fouier series , plotting first 50 terms...

Hi, a school question asked me to plot 50 terms of below fourier series. I need some help programming this plz.

(4/pi)*sum (sin (2k-1)*x/(2k-1), k=1..infinity) (k+1,k=0..n)

## Decomposing powers...

I have a long list of integers looking like

725  =  5^2 * 29

1125 =  3^2 * 5^3

2048 = 2^11

4752 = 2^4 * 3^3 * 11

For all of them I need to extract  base & exponents, namely

for  725:   [5,2, 29,1]

for 1125: [3,2, 5,3], etc

"op" gets lost for integers like  2048, power of a single number.

How to do this ?...  Thanks.

## Performance impact of nested procedures?...

If a sub-procedure A is defined inside another procedure B, and procedure B is called in a performance-critical inner loop, will the Maple interpreter read the definition of A again every time procedure B is called? I'm wondering if I should just avoid nested procedures, as how you would write programs in C, as opposed to Pascal which allows nested procedures.

## Maple 2020 Video refreshing Problems after interac...

Hello, I am trying to fix the problem reported below.

I am using the 64 bit version of Maple 2020.1. I am experiencing similar problems with other java applications. So I believe it must be something related to Java.

Moreover, it looks like the local refreshing problem is following the cursor of the mouse, therefore it must be something related to the interaction of the mouse with the GUI.

I am using a I7 CPU, 32 GB of Ram and a Nvidia Geforce RTX 2070.

Is anyone experiencing something like this? How can I fix this?

## initializing my random variables...

Hi,

I have a small problem initializing my random variables. When I run the sheet with the!!! button, the values do not change. Do you have any ideas?

Thanks

QinitierVariables.mw

## Edit Array/Matrix directly via DataTable / Change ...

Hello Everyone,

I am fairly new with Maple, but I am slowly getting the hang of it.

For a university project I need to be able to create a form where a user can input a matrix manually.
Also, I need to have something like a ComboBox where I can input how many rows that matrix will need. (1-20 or so)

I have solved the latter part by adding a "When Use"-Code that sets my Array/Matrix of the DataTable to be a Zero Matrix with the correct dimensions in accordance with the value chosen in the ComboBox.
(This is for a composite calculation, the ComboBox gives the number of plies, the matrix defines the ply orientation)

I then expected that the ZeroMatrix would serve as the baseline and the user can then manually edit the Matrix to be the correct values manually, but this gives me the error message that the DataTable cannot be edited.
I suspect the ZeroMatrix is now the "Master", because I defined it via Code.

Working with "visibleRows" did not help, because it does not change the matrix size only the size of DataTable and the user can still scroll down.

What I need is that I have a fully editable DataTable with exactly the number of rows that I specified using the ComboBox.

Does anyone of you perhaps have an idea what I could do to achieve this?
Any help would be fantastic! :)

Best Regards,
Lennart

## Creating a gradient with one level curve...

I have been stuggling with this for a few hours. I have my function 4x^2+9y^2. I have my point (2,1,25). I found my gradient to be 16i+18j. I want to plot the level curve that contains the point (2,1,25) and the gradient together.

I know how to graph multiple level curves but not one.

## How to pdsolve(diff( f(a,b), a+b) = diff( f(a,b),a...

How to pdsolve(diff( f(a,b), a+b) = diff( f(a,b),a))?

My personal edition of Maple 2020 throws java-lang-thread for every plot3d. No further output is provided by Maple. How can I further troubleshoot this?

Dave

I am trying to use the command FileTools[Text][ReadFile] to import the contents of a text file as a string in maple, but I want to be able to identify when line breaks occur, instead of the white space that I get.

Is this possible?

## simplify - getting the "simplest" form.... ...

Recently i'm noticing that mathematica is basically a mind-reader with their FullSimplify function, whereas maple even with simple expressions does not show what I would consider optimal (I agree this will be somewhat subjective).

Here is a trivial example:
ex1:=(2*sqrt(N__s) + N__s + 1)/(2*N__s + 2);

none of these are any help
simplify(ex1);
simplify(ex1, size);
simplify(ex1, symbolic);
simplify(ex1, sqrt);
simplify(ex1, sqrt, symbolic);

The ideal expression I would like to see here is:
1/2 + sqrt(N__s)/(N__s + 1)

Am I doing it all wrong (suppose I don't know of this simple form beforehand)?

Mathematica gets it right - see the following screenshot:

I'm finding this a lot... especially when hyperbolic functions and sqrt's are involved ("symbolic" option helps sometimes, but often the expressions are still not what I would consider "simplifed").