## Create excel file with sheets of independent varia...

Given a excel sheet with data for regression as input column Y will be a dependent variable

Say a maximum of 120 independent variables are their

A function that takes excel as input with headers as in the excel file

Do pick all possible subsets of maximum size 5 that is sizes 2,3,4,5 only

Pick each and eleminate not to store them all together as otherwise storage will be a problem if more data

Copy only those subsets of independent variables to seperate seperate sheet

Only those subsets

where the variables are independent pairwise between them

Step 2 function

Then need to run a multiple linear regression on these subsets like training and test

And choose the best models I each of cases of number of variable

That is best with 2 variables

Again with 3 variables

Similarly 4 and 5

Atleast if possible upto 2 to 3 variables it will be good kind help with your guidance and what is possible

If you are not able give the program of train test regression with charts no issues

Kind help with atleast storing the independent pairwise subsets of size 2 and 3 into seperate sheets in a Excel file atleast

I will do the regression at my end

## Taking an excel sheet perform operation create new...

I will have excel sheet with minium 500 coulmns and 1000 rows say

For sample to explain my question I attach a demo excel

I am looking to find all 2 way multiplication and add them as columns to my excel sheet and return it as a new excel sheet say

The column names for the new 2 way column should be like the

header name of column you are multiply * the name of the other columsn

Now in sample file if i multiple column with name A with column with name B I get a new column with header A*B the header name should be inserted and

Below that all the elements of that A column multiplied  with that of B should come

I am looking to form columns for all possible2  way multiplication for the excel I will give.

As you can see the demo file

Excel_to_explain.xlsx

## Global setting of character size in maple 2022...

Hello!

I have changed the the global character size from 12 to 14 but it is not stable. Suddenly size 12 is coming up when a try to copy a row to a another row in the same worksheet.

It is very annoying!!

Any tips????

Regards

Kjell

## limit at infinity ...

Dear all

I have an equation obtained from partial derivable of some functions, I would like to compute the limit when my variable named Pe goes to infinity.

I hope to get a more appreciate presentation of my code to obtain the limit (  Pe -> + infty)

limit_infinity.mw

All derivative are well compute, but How can I add the limit as Pe goes to infinity

Thank you

## Issue with Mapleprimes on Laptop...

Hey everyone,

I've been experiencing some issues with Mapleprimes on my laptop. Whenever I try to access the website, it takes an unusually long time to load, and sometimes it doesn't even load at all. This is quite frustrating as I need to use Mapleprimes for my research work. I've tried accessing the website on other devices, and it works fine, so I'm confident that the issue is with my laptop. Has anyone else experienced this problem? Any suggestions on how to fix it?

## Kind help to implement the attached flow chart...

Kind help to implement the attached flowchart

Finding_Detour_using_alorigthm.pdf

## Strange Maple response with Font anti-aliasing ena...

Just experienced a strange response from Maple when I changed the Font anti-aliasing to enabled.

With Font anti-aliasing disabled I ran evalf(Pi,100) and Maple returned 100 digits - no problem.  I then did some other errands in other programs leaving Maple idle, when I came back I thought I would change anti-aliasing to enabled and see if maybe that's the reason why some users are experiencing icons disappearing etc..

Well I re entered and evalueated evalf(Pi,100) and Maple only output 10 digits.  Huh??? What!? Why?  changed font anti-aliasing back but no joy.  So I closed Maple and I got a pop up

Maybe it was hiding behind Maple I don't know but I don't think it was there until I closed Maple.  It seems this OpenJDK platform I believe is causing a lot of Maple issues.

Whoa!  That's really odd.  My restart was with Maple Font anti-aliasing enabled I performed a evalf(Pi,100) and no problem.  I changed to Font anti-aliasing disabled and evalf(Pi,100) presented me with 10 digits!

What the heck is going on.  This font anti-aliasing enabled caused my Maple to slow down as the screen filled up (as I recorded in a earlier post months ago) and now toggling anti-aliasing causes the outputs to not work as expected.  It's gotta be an open JDK issue. (FYI closing Maple did not produce the same pop-up as earlier - I expect idling maple for a while might)

## How can i re-install maple 18....

Dear Friends
On 22 March 2018, I received:

ORDER REFERENCE INFORMATION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Customer: Universidad Nacional Autonoma De Mexico, UNAM
Order Date: 3/21/2018
Order Number: 889668
Customer Purchase Order: 10972
For instaling MAPLE 18

Please see the at bottom of the mail

Best Regards

El 22 mar 2018, a las 11:05, license@maplesoft.com escribió:

Here is your copy of Maple 2018. And this is not a release to ignore!

People use Maple to do many different things, so it’s inevitable that each new release will include some features you care about and some features you really don’t need. However, Maple 2018 contains a large number of substantial enhancements to how you interact with Maple, which means you’ll benefit from this release no matter what you use Maple for.

You are receiving this email because you are a member of the Maplesoft Elite Maintenance Program (EMP). While you participate in this program, you are entitled to new product releases as they come out.

If you are a MapleSim user, note that, unlike in previous years, this email contains only your Maple entitlement information. If you are still an active EMP member when MapleSim is released, we will send your MapleSim information to you at that time.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you would like a physical copy of your product(s) shipped to you, please go to http://www.maplesoft.com/entitlements. You will need the email address that this email was sent to along with the order number.

ORDER REFERENCE INFORMATION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Customer: Universidad Nacional Autonoma De Mexico, UNAM
Order Date: 3/21/2018
Order Number: 889668
Customer Purchase Order: 10972

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

================================================================

================================================================

The following Purchase Codes activate this product:

[Purchase code deleted]

For the Maplesoft terms and conditions that govern your license to the above noted products, please refer to the Maplesoft End User License Agreement (EULA) found during installation. The Maplesoft EULA can also be found online at http://www.maplesoft.com/documentation_center/Maplesoft_EULA.pdf . You should review the entire Maplesoft EULA prior to activating your products.

SUPPORT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It is important that you follow the installation instructions contained with each product. If you experience any problems during installation, please visit the Maplesoft online technical support center at http://www.maplesoft.com/support.

For more information on activation, refer to the FAQ page at: http://www.maplesoft.com/support/FAQs/Activation.

Please refer to your order number (889668) in any correspondence to customer service.

Kind Regards,
Maplesoft Customer Service
http://www.maplesoft.com

© Maplesoft, a division of Waterloo Maple, Inc., 615 Kumpf Drive, Waterloo, ON, Canada, N2V 1K8, customerservice@maplesoft.com. To opt out of all commercial email communications from Maplesoft, please click here.

## why Maple's worksheet content disappears when open...

I found a new problem in Maple 2023 on windows 10.  But it is more of an annoyonus. This is what happens:

I can have a worksheet open and running somecode with lots of output generated on the screen. Everything displays fine.

Now I go and open a new application not related to Maple at all, for example if I open the task manager, this causes the Maple screen to immediately go all BLANK ! Yes, all the display is gone. I have no idea why opening a new application in new window could cause this.

Everything disappears from the worksheet except for the worksheet frame. All the menus are gone also.

But resizing the worksheet window makes everything to appear agin due to the repaint process, But I need to resize the worksheet few times to get everything to repaint fully.

So the content is still there, but it just do not show/repaint.

Note that Maple does NOT freeze or anything, it is still running and the content is there, it is just that the content becomes not visible due to opening a new application window on the side.

I have never seen anything like this in any other application on windows. I also never had this problem on same PC with Maple 2022.2.

Anyone else noticed this problem?  This is reproducible all the time. Sometimes the content will display again on its own after short amount of time, but will be missing many menu items and missing side content and so on so I have to resize the windows to make repaint eveything again.

May be it is a Java problem. I do not know.

I have the same system as described in this post

I will make a movie to show this very soon but I am waiting for something to finish running before I do this so I can save all my work.

Windows 10 pro, running Maple 2023 with two monitors.

Here is a small movie. I made very small example which prints number on the screen in a loop. I added a Sleep in between so it does not take over the CPU just for illustration. In my real code there is no such Sleep command.

In this movie, we see that when I open the task manage window how the display in the worksheet is gone. In this example it comes back after few seconds but all the other items in the worksheet (menus etc..) are still missing. Resizing the windows makes them appear again. In my actual code, due to the larger content, the whole worksheet remain not visible for much longer each time (I waited 5 minutes and more for it to repaint), but still had to resize it to make everything visible as in this example.

Can someone else reproduce this?

```for n from 1 to 1000000 do
print("n=",n);
od;```

## Relude surface : lines planes, 3D geometry...

Hi, I am looking to illustrate my lecture with Maple figures. This is in a French context, using French vocabulary. I am including my mathematical development in an appendix. I would appreciate any suggestions. Thank you for your help

## How to compute definite integral...

> int((1 - x)^r*(-2*x + (-2 + x)*log(1 - x))/(2*x*log(1 - x)^2), x = 0 .. 1) assuming 0 <= r

Expected result is:

1 + r - r * ln(1 + r) - 1/2 * ln(2 * Pi * (1 + r)) + lnGAMMA(1 + r)

## (Bug) Units package gives different output...

Hi,

Can anybody explain why

with(Units):
A := 1, 2, 3:
B := 4, 5, 6:
AB := B - A;

outputs 11, but the output is 3, 3, 3 without the Units package?

Best regards,

Mikkel

## Why is zip slower than `~`?...

For two nonempty lists (of the same length),

`F~(list1, ` \$`, list2); # space-dollarsign`

is (almost) equivalent to

`zip(F, list1, list2);`

However, it appears that in practice, using ``~`` can be faster than its equivalent `zip` version.
Here is a typical test:

 > restart;
 > x := combinat:-randperm(10^7): y := combinat:-randperm(10^7):
 > undefine(f);
 >
 memory used=0.62GiB, alloc change=1.21GiB, cpu time=51.35s, real time=14.77s, gc time=42.55s
 >
 memory used=0.52GiB, alloc change=-4.00MiB, cpu time=53.88s, real time=16.25s, gc time=44.51s
 >
 (1)
 >

But I cannot find any explanations in the documentation (as well as What is Maple's equivalent to Mathematica's MapThread?). Does anyone know why?

## How does the range option affect the way dsolve/nu...

I recently got stuck on a strange behavior of odeplot which did not return any result (only the axes were drawn).
Convinced that the solution of the differential system was correctly constructed, I noticed that drawing it, without using odeplot, gave me the correct result.
I then discovered that the range option (which I mistakenly defined) was the cause.

But this led me to the following question: what does this option really do?

Here is a notional example. The two questions are at the end of the worksheet.

 > restart:
 > interface(version)
 (1)

EXAMPLE 1

 > sol := dsolve({diff(x(t), t) = t, x(0)=0},numeric, events=[[x(t)=2, halt]], range=0..1)
 (2)
 > # As range is defined up to t=1 and x(t) = t^2/2 = 2 for t=2 it seems "normal" # for the event not to be fired: Tend := sol(eventfired=[1])[]
 (3)
 > # But the limitation induced by range seems ignored by odeplot: plots:-odeplot(sol, [t, x(t)], t=0..4);

EXAMPLE 2

 > sol := dsolve({diff(x(t), t) = t, x(1.1)=0},numeric, events=[[x(t)=2, halt]], range=0..1)
 (4)
 > # For the same reason the event is still not fired here Tend := sol(eventfired=[1])[];
 (5)
 > # odeplot doesn't return any plot. # # This seems logical given that range=0..1 is not consistent with the initial # condition set at t=1.1 # Nevertheless the warning message looks contradictory with the fact that the event is not fired plots:-odeplot(sol, [t, x(t)], t=1.1 .. 4);
 > # Remark: using refine seems to fix this problem plots:-odeplot(sol, [t, x(t)], t=1.1 .. 4, refine=1);
 > # Let's try to plot the solution differently. X := proc(s) eval([t, x(t)], sol(s)) end proc: plot([seq(X(s), s=[seq](1.1 ..4, 0.1))])
 > # Why is the solution calculable? # Why can't odeplot calculate it?
 >

Please note that the last couple of commands strangely overpasses the < Warning, cannot evaluate the solution further right of 2.2825424, event #1 triggered a halt > limitation.

## Why is map slower than `~`?...

For a list containing at least one element,

`F~(list0); # element-wise`

is (almost) equivalent to

`map(F, list0);`

However, it seems that in practice, using ``~`` can be faster than its equivalent `map` version.
Here is a typical test:

 > restart;
 > w := [`\$`](0 .. 1e4): x := [`\$`](0 .. 2e3): y := [`\$`](0 .. 3e2): z := [`\$`](0 .. 4e1):
 >

# Compute a generalized outer product of  and  without using the inefficient `ArrayTools:-GeneralOuterProduct`.

 >

memory used=282.53MiB, alloc change=0.59GiB, cpu time=21.67s, real time=7.41s, gc time=17.33s

 >

memory used=230.48MiB, alloc change=-4.00MiB, cpu time=23.26s, real time=8.67s, gc time=17.71s

 > evalb(p2 = p4);

 >

But I cannot find any explanations in Comparison of element-wise operators and map function or Difference between 'map' and '~' (element-wise operation). Does anyone know why?

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