Hello,

I have a quite big program designed with packages and subpackages.

I realized that i'm not to well understand the operation of local/ global/ export variables in this case.

Let's detail the issue.

I consider a package like this :

MAIN PACKAGE:=module()

local XM

global YM

export ZM

      SUBPACKAGE1:=module()

      local X1

      global Y1

      export Z1

      end module;

      SUBPACKAGE2:=module()

      local X2

      global Y2

      export Z2

      end module;

end module;

Question:

Can you describe in the simpliest way the rules for accessing to the variables in the case the variables are local/ global/ export and in the case you are writting procedures inside the MAINPACKAGE or the SUBPACKAGEs ?

In others words may you help me to answer to these questions  ?

Is the local variable XM accessible to the procedures used in SUBPACKAGE1? no
Is the local variable X1 accessible to the procedure used in MAINPACKAGE ? no

Is the global variable YM accessible to the procedures used in SUBPACKAGE1? yes
Is the global variable Y1 accessible to the procedure used in MAINPACKAGE ? yes

Is the export variable ZM accessible to the procedures used in SUBPACKAGE1? yes
Is the export variable Z1 accessible to the procedure used in MAINPACKAGE ? yes with the syntax SUBPACKAGE:-Z1

I let my opinion but i need certainty on these points...

I attach a first draft that i would like you help me.

AboutModuleLocalGlobalExport.mw

I thank you in advance for your help.

I could not find a function in StringTools package which removes all substrings (not single characters) from one long string directly. 

For example given a Latex string 

s:=" \\left \\int x \\,dx \\left";

And I want to remove all "\\left"  from it, which results in "  \\int x \\,dx "

In Mathematica, there is a function called StringDelete which removes all occurances of the substring in one call. Like this

s = " \\left \\int x \\,dx \\left";
StringDelete[s, "\\left"]

In Maple, I tried StringTools:-Remove(x->evalb(x="\\left"),s) and this did not work.Also tried

s:=" \\left \\int x \\,dx \\left";
StringTools:-Remove(x->StringTools:-Compare(x,"\\left"),s)

But this returned "leftintxdxleft"

And StringTools:-Delete needs a range, which one then has to first find.

I found this:

s:=" \\left \\int x \\,dx \\left";
idx:=[StringTools:-SearchAll("\\left",s)]; #returns index of first character in the string
StringTools:-Delete(s,idx[1]..idx[1]+4); #this only remove the first one. Need to loop to remove all.

Which returns the first substring. So one has to make a loop and keep removing all substrings found from the call to StringTools:-SearchAll

This is all too much work. But can be done.

The question is: What is the simplist way to remove all substrings from one string? All substrings are the same and the substrings can be more than one character.

Here is another example

s:="1234566X6Y67890A6BC66DEFGH";

And want to remove all "66" substrings, so the result will be

"12345X6Y67890A6BCDEFGH";

I am sure there must be an easier way to do this in Maple than having to call 2 or 3 functions and using a loop, but I could not find it so far. 

What would be the closest function in Maple to Mathematica's StringDelete? 

Requesting a code to compute (and graph) the following self referencing sequence:

a(1)=1. If a(n) is a novel term (seen for the first time) then a(n+1)= d(a(n)) where d(k) is the number of divisors of k. 
if a(n) has been seen before then a(n+1) = a(n)+m where m is the least prior term which has not already been used in this way (once m is used it cannot be used again).

Sequence starts:

1,1,2,2,3,2,4,3,5,2,4,6,4,7,2,5,7,11,2...,

note that there are often multiple copies of the least unused term, which might make accounting for them tricky. 

Thanks in advance 

hello dear maple maple users.

I'm trying to solve this system of equations using fsolve but i'm geting this unrealistic curve.

I don't know exactly how, can help me understand!!!!!.

fsolve.mw

I am working with the JetCalculus package along with the DifferentialGeometry package. Notation: if there are 2 independent variables (x,y), then u[1,2] would now represent the 3rd mixed partial derivative of u, once with respect to x and twice with respect to y. Please check Example 3 here, https://de.maplesoft.com/support/help/Maple/view.aspx?path=DifferentialGeometry/JetCalculus/TotalDiff

If I have an expression like u[1,0]+f(u[0,0])*u[0,1]+u[1,1]*u[0,3], then I am looking for a procedure which gives me the Lead derivative term. In the example above, it is u[1,1]*u[0,3], and then I can find the lead coefficient, i.e u[1,1].
Please note that the Lead derivative is not unique and can have several terms. For example, orders are the same for u[1,1] and u[0,2].

Idea: If I can find a way to extract the subscripts and do operations on them, then it would be very helpful. 
Any help/guidance is much appreciated. Thanks.
EDIT 1: LeadingDerivative command is not the solution for me.

Dear maple users,

A fine day wishes to all.

How to replace a value in already computed data value.

In my problem, I have evaluated a set of values (with help of #ma1 := evalf(seq((A4(t)), t = 0.0..1, 0.1));)  

ma1 := 0., .1941703021, .3203871063, .4089371834, .4712881303, .5145114133, .5435036431, .5617715009, .5718586242, .5756277760, .5744585726

I need to change 0 value as a 1.

I have used subs(ma[1]=1,ma1), but its coming wrong.

diff(w(r, theta), r)/r + diff(w(r, theta), r, r) + diff(w(r, theta), theta, theta)/r^2 = r^3*cos(3*theta)

Can it be solved without boundary conditions?

Hi there.

Following by https://www.mapleprimes.com/questions/232199-Bug-In-EllipticCPi

there is some strange behavior of EllipticPi - this function return complex answer when nu>1

WolframAlpha and some another online calculators return real values - just real part of Maple's value.

Why Maple's EllipticPi return complex answer?

help.mw

How to solve Linear first-order PDE by the Lagrange method?

dx/(x) =dy/0=dt/0=du/3=dv/v=dw/w, where x,y,t are independent variables and u,v,w are dependent variables.

hello guys,

I want to plot the phase plane between F and m when:

F := 736*R^4/sqrt((-1380*Pi*R*m(r)^3 + 368*R^4 - 1587*m(r)^2*R^2 + 1280*m(r)^2*a)^2);
R := X^(1/3)/(-l^2 + 4*a) - 3*l^2*m(r)^2/X^(1/3);
X := m(r)*l^2*(sqrt((27*l^2*m(r)^4 - 16*a^2*l^2 + 64*a^3)/(-l^2 + 4*a)) + 4*a)*(-l^2 + 4*a)^2;
 

and

m := (l^2*r^2 + r^4 + a*l^2)/(2*l^2*r)

for positive constant a and l

please guide me,

thanks

Hello everyone. I took part in a project in which we had to solve problems with Maple 2015. The managers gave us a permanent license. However recently I had trouble on my computer and now Maple doesn't work anymore because it somehow lost the license. The project ended last year, so I can't really ask them anymore. Is there any way to get the license working again? I checked on the site but didn't found anything useful and I'd really need it for the final exam of the last year of high school...

Thanks in advance!

Sorry file was not attached
 

Download CALC-0191-Upload.mw

When I have an operation to perform with Maple, my first reflex is to use the "native" Maple procedure(s) because it seems logical to think that they have been written in order to reduce the memory used and/or the execution time.
Unfortunately, this feeling is not confirmed by reading some of the answers provided on this site.

The attached file shows 4 ways (among probably several others) to center and reduce (by columns) a random matrix.
Amid them is the Statistics:-Scale procedure which appears not to be the most efficient (even a double loop outperforms in term of time).
This is just an example among many others (for instance Statistics:-Select can be easily outperformed)

So my question: why deceive the user with magic functions which sometimes have a very relative efficiency?

Scaling_efficiency.mw

Hello

I have used Maple almost daily for the last four years, but a few days ago two students approached me with an issue I had never encountered before. However, it had happened to both of them within a few weeks.

They described the issue as follows: When they opened a random Maple document and they tried to type in simple operators (like +, - or *), Maple would instead write an odd symbol, which none of them recognised as a mathematical symbol.

As they could not find a way to solve the problem within Maple, they tried restarting their computers. When they afterwards reopened Maple, the problem was gone and the operators worked as expected again. Neither of the students has experienced the issue since.

During the last few days, I have been trying to replicate the issue myself without success. Therefore, I also don't have any screenshots to share, so hopefully my simple explanation is enough.

My questions are: Has anyone heard about this issue before? Does anyone know what might have caused it? Is there a way to replicate it and/or prevent it from happening again in the future?

I hope someone is able to clarify it a bit for me! :)

Regards,

Frederik

How to find the location of the poles of a normal chord in an ellipse ?
Here is my code :

restart; with(geometry); with(plots); `local`(O);
_EnvHorizontalName := x; _EnvVerticalName := y;
corde := a*x/cos(theta)-b*y/sin(theta) = a^2-b^2;
isolate(corde, a/cos(theta));
Error, (in isolate) a*x/cos(theta)-b*y/sin(theta) = a^2-b^2 does not contain a/cos(theta)
eq1 := (a^2-b^2)*X/a^2 = a/cos(theta);
c := solve(eq1, cos(theta));
eq2 := (a^2-b^2)*Y/b^2 = -b/sin(theta);
s := solve(eq2, sin(theta));
lieu := simplify(expand((a^2-b^2)^2*X^2*Y^2*(c^2+s^2 = 1)));
allvalues(eliminate({eq1, eq2}, theta))[1][2];
ell := x^2/a^2+y^2/b^2 = 1;
P := [a*cos(theta), b*sin(theta)];
tgP := x*P[1]/a^2+y*P[2]/b^2 = 1;

sol := solve({corde, ell}, {x, y});
tgP1 := simplify(x*rhs(sol[2][1])/a^2+y*rhs(sol[2][2])/b^2 = 1);

Drawing in a case
a := 5; b := 3; theta := (1/6)*Pi;

line(l1, corde); conic(co, ell);
Pole(P1, l1, co); coordinates(P1);
a := 5; b := 3; theta := (1/6)*Pi;
Ell := implicitplot(ell, x = -a .. a, y = -b .. b, color = red);
Cor := implicitplot(corde, x = -a-1 .. a, y = -b-1 .. b, color = blue);
TgP := implicitplot(tgP, x = 0 .. 10, y = -5 .. 10, color = magenta);
TgP1 := implicitplot(tgP1, x = -5 .. 10, y = -5 .. 10, color = magenta);
lieu := subs(X = x, Y = y, lieu);
subs(x = 125*sqrt(3)*(1/24), y = -27/8, lieu);
Lieu := implicitplot(lieu, x = -a .. a, y = -b .. b, color = green);
dr := draw(P1);
display([Ell, Cor, Lieu, TgP, TgP1, dr], axes = normal, view = [-10 .. 10, -10 .. 10], scaling = constrained);

Why the drawin of the location (lieu) does not appear ? Thank you.