Hello,
I recently discovered the "Physics" package wich provides tools for manipulating abstract vectors (non-component).
In the "Physics:-Vectors", an orthonormal basis (i,j,k) is available and my main concern is how to generate arbitrary other 3D orthonormal bases to be able to calculate results in "vectorial form" without manipulating vectors' components.

To better explain my needs I have setup a kind of minimal example in the attached file where some questions are asked.

Thanks in advance for any feedback.

orthonormal-triads.mw

Download orthonormal-triads.mw

This used to work in Maple 2022.  Something is broken in 2023. 

Download simplify-piecewise-bug.mw

When printing a Maple Worksheet  often I go in the PrintPrewiev of the Mac and then select some sides to print.

This is not working anymore since I have updated from Maple 2021 to Maple 2023.

Is this known ?

Any help for his ?

Can anyone assist with this error please?

Download Asst_3_Q4b.mw

I can import maple, but I get an error when importing namespace/symbols:

import maple.namespace as mpl

Hi!

I'm having problems with my maple not saving. I get no error message and no windows pop up.
The error occurred after the summer holidays in Maple 2022. I use Windows 11, everything is up to date. Have no Anti-virus programs.

  I have tried the following after I discovered the error:
- To install Maple 2023
- Uninstall and delete all maple folders, then reinstall Maple 2023
- Pressed Ctrl + s
- Press "Save as..."
- Pressed on the floppy disk/save icon
- Restarted computer and updated windows
- Run Maple as administrator

The only thing I can be allowed to do is:
- Ctrl + p
- Print to PDF/printer

Really hope you can help!

Since strings are not mutable objects in Maple, the package provides two procedures, StringTools:-OldStringBuffer and StringTools:-StringBuffer, which appear heavily correlated with Java's  and . 

The help page of StringBuffer claims that use of a is much more efficient than the naive approach: 

(*
`G` and `F` are taken from the link above.
*)
G := proc()
   description "extremely inefficient string concatenator";
   local   r;
   r := proc()
       if nargs = 0 then
           ""
       elif nargs = 1 then
           args[ 1 ]
       else
           cat( args[ 1 ], procname( args[ 2 .. -1 ] ) )
       end if
   end proc;
   r( args )
end proc:
# # This can be transformed into an O(1) algorithm by passing a string buffer to the recursive calls.
F := proc()
   description "efficient version of G";
   local    b, r;
   b := StringTools:-StringBuffer();
   r := proc()
       if nargs = 1 then
           b:-append( args[ 1 ] )
       else
           b:-append( args[ 1 ] );
           procname( args[ 2 .. -1 ] )
       end if
   end proc;
   r( args ):-value()
end proc:
s := 'StringTools:-Random(10, print)' $ 1e4:
NULL;
time(G(s));
                             5.375

time(F(s));
                             1.125

But why not use the built-in cat directly? 

time(cat(s));
                               0.

time(StringTools:-Join([s], ""));
                               0.

Clearly, this is even more efficient. 

Here is the last example in that link. 

FilterFile := proc( fname::string, filter )
   local   b, line;
   b := StringTools:-StringBuffer();
   do
       line := readline( fname );
       if line = 0 then break end if;
       b:-append( filter( line ) )
   end do;
   b:-value()
end proc: # verbatim 
filename__0 := FileTools:-JoinPath(["example", "odyssey.txt"], 'base' = 'datadir'):
filename__1 := URL:-Download("https://gutenberg.org/ebooks\
/2600.txt.utf-8", "War-and-Peace.txt"):

fclose(filename__0):
    time[real]((rawRes0 := FilterFile(filename__0, StringTools:-Unique)));
                             0.223

fclose(filename__1):
    time[real]((rawRes1 := FilterFile(filename__1, StringTools:-Unique)));
                             1.097

Nevertheless, 

close(filename__0):
use StringTools, FileTools:-Text in
	time[real]((newRes0 := String(Support~(fscanf(filename__0, Repeat("%[^\n]%*c", CountLines(filename__0))))[])))
end;
                             0.118

close(filename__1):
use StringTools, FileTools:-Text in
	time[real]((newRes1 := String(Support~(fscanf(filename__1, Repeat("%[^\n]%*c", CountLines(filename__1))))[])))
end;
                             0.580

evalb(newRes0 = rawRes0 and newRes1 = rawRes1);
                              true

As you can see, these experiments just tell an opposite story. Isn't the so-called "StringBuffer" obsolete today? 

Maple (2023.1) opens regularly but I cannot use "open" or "save" or "save as" and after opening Maple I no longer can close it.

That is a big problem for me.

The issue is on my new laptop Lenovo L13 Yoga with Windows 11.

Any suggestion? Thanks

hi i have a problem where maple dosent have a varible theta inside cos and sin and when i give it a size it dosent solve the equtation 

Delay differential equations in Chebfun lists 15 examples "taken from the literature". Many of them can be (numerically) solved in Maple without difficulty, yet when I attempt to solve the  in the above link, Maple's internal solver `dsolve/numeric` just halts with an error. 

plots:-odeplot(dsolve({D(u)(t) + u(t)**2 + 2*u(1/2*t) = 1/2*exp(t), u(0) = u(1/3)}, type = numeric, range = 0 .. 1/3), size = ["default", "golden"]);
Error, (in dsolve/numeric) delay equations are not supported for bvp solvers

Even if I guess an initial (or final) value artificially, the solution is still less reliable (For instance, what is the approximate endpoint value? 0.26344 or 0.2668?): 

restart;
dde := D(u)(t) + u(t)**2 + u(t/2)*2 = exp(t)/2:
x__0 := 2668/10000:
sol0 := dsolve([dde, u(0) = x__0], type = numeric, 'delaymax' = 1/6, range = 0 .. 1/3):
plots['odeplot'](sol0, [[t, u(t)], [t, x__0]], 'size' = ["default", "golden"]);

x__1 := 26344/100000:
sol1 := dsolve([dde, u(1/3) = x__1], type = numeric, 'delaymax' = 1/6, range = 0 .. 1/3):
plots['odeplot'](sol1, [[t, u(t)], [t, x__1]], size = ["default", "golden"]);

Compare:  (Note that the reference numerical solution implies that its minimum should be no less than 0.258 (Is this incorrect?).).

And actually, the only known constraint is simply u(0)＝u(⅓) (so neither value is known beforehand). Can Maple process this boundary condition automatically (that is, without the need for manual preprocessing and in absence of any other prior information)?
I have read the help page How to | Numeric Delay Differential Equations and Numerical Solution of Difficult ODE Boundary Value Problems, but it appears that those techniques are more or less ineffective here. So, how do I solve such a "first order nonlinear 'BVP' with pantograph delay" in Maple?

When i try to log on to my maplesoft acount on Maple 2023 i get a messeage saying "Sign in Error: Please check your credentials and try again." i have done this multiple time double checked my password and everything, but it won't let me log on... what do i do?

I am using Maple 2023.

When using PDE Numeric Help Side the text sides is not smooth moving when scrolling downwards or upwards.

Any advice what to do????

Kjell

GraphTheory:-GraphEqual says that G₁ and G₂ are equal, but GraphTheory:-AllPairsDistance gives different results instead: 

Download allpairs.mw

So, which one is incorrect? Any reasons?

Since I began to use Maple for teaching back in 2014 (now on 2023 version), the following happens to some students. 

While they are in math mode, the Maple engine suddenly stops being unable to do anything (even 2+2). Only way to solve this is to start a new document or restart Maple. I have seen this issue on both Mac and PC version. 

So my question is what causes this? 

I installed Maple 2023.1 update and immediately noticed a problem with the worksheet editor.

Specifically, the editor seems to be replacing "<" with "!" in the maple code. I first noticed the problem with code copied from the maple code editor into a worksheet, but then noticed the same problem with code on another worksheet which was loaded from file. Thus, it seems the problem is actually in the worksheet editor and not the copy paste function.  Note that the problem occurred immediately on reloading files after I restarted maple from the update. Normally, when this occurs, it starts after Maple has been loaded for an hour or more. Fortunately, when I restarted Maple and reloaded files, the problem seems to have cleared itself.

I have attached images showing the maple screen with the error, and also the specific code copied from the code editor to a worksheet for comparison.  I have also attached the worksheets in which I saw the problem. For now my goto workaround is to save and restart because the problem does not seem to corrupt the actual files even when I save them.

Attachments: chain.mw  chain2.mw