## Physics[Vectors] vector type...

Is there  a specific type name for vectors in Physics[Vectors]?  Specifically, Let's say we want to write a proc whose argument is expected to be a (Physics) Vector, as in  these (trivial) demos:

```with(Physics[Vectors]);

f := proc(a_::???)
return a_ . a_;
end proc:

g := proc(a_::???, b_::???)
return a_ &x b_;
end proc:
```

What do we put in place of "???".

## Questions re using Maple cloud...

I want to create and modify the same worksheet at different times on two different computers in two different locations.

To avoid transferring files between the two machines, it seems most convenient to reference all objects within Maple cloud.

I am a beginner at this and have several questions:

1) I have downloaded the DirectSearch package as directed in help text but the only result from issuing the command kernelopts(toolboxdir) is " ".

How can I establish a path which enables my worksheet to execute commands within this package?

2) How can my worksheet invoke procedures within my .mla file referencing only objects in Maple cloud?

How can I update (save and delete procedures) within my .mla file?

## How to simplify Differential output?...

Maple knows how to obtain differntials using D.

So typing  D(x*y) it gives   D(x)*y+x*D(y)

But what I want is given as input  D(x)*y+x*D(y) have Maple return back D(x*y)

Nothing I tried work. I tried simplify and convert(...,D)

I am looking for a function that takes an expression with differentials like the above output, and return, if possible ONE differnetial in the form  D(  f(x,y) )

What I mean, given as INPUT any of these expressions on the RHS in the image below

To return back  the  D(...)  in the LHS above. I know Maple can do it going from the LHS to the RHS. But I want the other way around.

Does Maple support such operations?

Maple 2022.1

## How to split a list into character set and integer...

If I have a list say

L:=[1,"2","3",4,5,"6",7,8,9,"10"]

Now i would like to have fuction which takes L as input say    split(L)

and would return two list one with characters from that namely ["2","3","6","10"] and another of integers [1,4,5,7,8,9] like this

The list will have characters and integers only

Kind help it will be acknowleged

## Initialization diagnostics questions...

Q1: clicking on a variable in the attached I get

What does it mean and how can I fix that when it happens?

Initialisation_diagnostics_error.msim

Q2: Why are initial conditions which are set to "Ignore" listed as "Guess"?

I intend to use the initialization diagnostics to filter a model for components that have initial conditions set. In the attached example (excerpt from a larger model), this does not work the way I want it to (i.e. I don't want P1 to be listed a guess).

Init_diagnostics_ignore_listed_as_guess.msim

Q3: The app seems to be a powerfull tool. Is it explained somewhere how to use the app to debug a model?

## How to find Dirac gamma matrix?...

Given a diagonal metric of signature (++- -)  for example the diagonal elements are [1,1,-1,-1], then how to find the Dirac gamma matrix in the standard representation or any representation.

## Difficultu with pointplot...

restart;
with(LinearAlgebra);
with(plots);
NULL;

EqBIS := proc(P, U, V) local a, eq1, M1, t, PU, PV, bissec1; a := (P - U)/LinearAlgebra:-Norm(P - U, 2) + (P - V)/LinearAlgebra:-Norm(P - V, 2); M1 := P + a*t; eq1 := op(eliminate({x = M1[1], y = M1[2]}, t)); RETURN(op(eq1[2])); end proc;
NULL;
A := <4, 8>;
B := <4, 2>;
C := <1, 4>;
EqBIS(A, B, C);
NULL;

Cen := proc(M, N, R) local eq1, eq2, sol; eq1 := EqBIS(M, N, R) = 0; eq2 := EqBIS(N, M, R) = 0; sol := simplify(solve({eq1, eq2}, {x, y})); RETURN([subs(sol, x), subs(sol, y)]); end proc;
Cen(A,B,C):

CircleParm := t -> [(-t^2 + 1)/(t^2 + 1), 2*t/(t^2 + 1)];
P1 := Transpose(convert(CircleParm(1/4), Vector));

P2 := Transpose(convert(CircleParm(5), Vector));
P3 := Transpose(convert(CircleParm(-1/10), Vector));
P4 := Transpose(convert(CircleParm(-3/2), Vector));

C1 := Transpose(convert(Cen(P1, P2, P3), Vector));
Pts := [P1, P2, P3, P4, C1];

display(implicitplot([x^2 + y^2 - 1], x = -2 .. 2, y = -4 .. 2, colour = [blue], scaling = constrained), pointplot(Pts, symbolsize = 16));
Error, (in plots:-pointplot) incorrect number of coordinates in points data
NULL;Why this error. Thank you.

## How to relabel only a subset of vertex of G...

How relabel only one particular vertex of G of my choice. others will remain as it is

Function I want to create

V:=Vertices(G):

Relabel:=proc(Graph::G,S,K)

I want to relabel only that particalur S subset V of G where S is list with say the K is a list of labels to be assigned the corrsponding vertices i paased in S.

end proc;

Where v:=V[i] the vertex , k can be a character like       a or 1 or [1,2,3,4] or anything

## fyi, internal error generated by odetest on series...

To Maple support,.

fyi,

internal error generated on this ode when trying odetest

 > interface(version);

 > restart;
 > ode:=x^3*diff(y(x),x\$3)+x^2*diff(y(x),x\$2)-3*x*diff(y(x),x)+(x-1)*y(x)=0; sol:=dsolve(ode,y(x),'series',x=0): odetest(sol,ode,'series','point'=0);

Error, (in odetest/series) complex argument to max/min: 1/4800*((-79*I+3*83^(1/2))*3^(1/2)+9*I*83^(1/2)-79)*(316+12*83^(1/2)*3^(1/2))^(2/3)+1/12*I*(316+12*83^(1/2)*3^(1/2))^(1/3)*3^(1/2)-1/12*(316+12*83^(1/2)*3^(1/2))^(1/3)+20/3

## How to increase graph qaulity according to desire?...

He Seniors, How to increase the quality of graph by puting command in ploting command according to required desire

Graph_qaulity_help.mw

## A bug in convert...

Hi,

I found a bug in convert, please help me if you know a solution.

When we use the code

convert(U(xi)^2*y(xi)^5,list);

we get

[U(xi)^2, y(xi)^5]

but when we use

convert(U(xi)^2,list);

we obtain

[U(xi),2]

while I expect the following result:

[U(xi)^2]

* "convert" is one part of my code for solving a problem. Sometimes there are cases that just exist one function instead of >1.

Since I want to keep my codes general, hence I need [U(xi)^2] in response to convert(U(xi)^2,list).

## simple problem - yet difficult i found...

A polynomial divided by another polynomial of lower degree. I want to find the remainder and quotient. How do I get.

The question is what should I add to the numerator get perfect division when x-3 x  -12 x+19 is divided by x2+x-6.

I shd get the answer as 2x+5 to be added since the remainder is -2x-5.   (Note that x-3 x  -10 x+24 is excatly divided by 2+x-6.

Can any one state the code to get the answer.

Quotient ( ) and Remainder (  ) codes , i tried, donot know how to use them.

Thanks for help. Cheers. RK

## What is generating the R[0] term, and how do I rem...

I'm using Maple 2021, and my Euler-Lagrange equation is coming out with a R[0] term that should not be there. I want to know what is causing this error and how I can fix it.

Lagrangian

 (1.1)

Time Equation

 (2.1)

## How to define, in a module, a typesetting rule to ...

Dear All,

I'm wondering if there is a simple way to define, given a "module" that protects "e" as a global, to allow the user to write e[0], e[1], e[2], e[3], e[inf] such that I calculate with e[4] but I display e[inf]. And if I type in e[inf], it translates behind the curtain of the module e[inf] into e[4] such that I keep my indexes 0-4 for the handling of my entities.

I hope I made myself understood ;)

I was woundering if there is some way with the standard "TypeSetting Module" ?

Sincerely

Ivar

## Sparse matrixplot with column labels: Is that poss...

How can I achieve something like this (i.e. an output in a worksheet)?

It is important that the variables of the lables match the columns.

In the attached file is a typical dataset. A display of row lables would be optional.

Context: Easier interpretation (of the structure) of a Jacobian and subsequent manual solving the equations of interest that correspond to the rows.

Labels_for_sparse.mw

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