The (Induced) Subgraph Isomorphism computational problem is, given H and G, determine whether there is a (induced) subgraph isomorphism from H to G. See https://en.wikipedia.org/wiki/Induced_subgraph_isomorphism_problem

In Maple, IsSubgraphIsomorphic(G1,G2)  returns true if G1 is isomorphic to some subgraph of G2. However, it does not provide options for induced subgraphs. For example, 

with(GraphTheory):
claw:=CompleteGraph(1,3);
g:=CompleteGraph(2,2,2,2):
DrawGraph(g);
IsSubgraphIsomorphic(claw,g) #true

So the graph g contains a claw as a subgraph. But every claw in graph g  is non-induced. So g does not contain any induced claw. Maple does not appear to have this feature to determine if a graph contains a induced subgraph isomorphic to another graph. It is unclear whether we can modify some code in IsSubgraphIsomorphic  to achieve this goal.

Download n=1_analytical.mw

ode1 is Lane emden equation that can be solved analytically for n=0,1,5 .

For other values of n it needs to be solved numerically.

My question is how to proceed and use the numeric result in ode2 with bcs mentioned and get same or close result to analytical one. I am trying to verify alpha. In the worksheet i have chosen n=1 because i want to learn how to deal with numeric solution for which i already have the answer to verify. If ode2 also needs to to solved numeric its ok. The point is to get at the derivative value from various alpha values for different n like 3. Please help and let me know if additional info is needed.

Hello

I re-opened my maple file and got the following error code:

"There were problems during the loading process. Your worksheet may be incomplete"

I have attatched the original file and todays backup file.

Backup:

D_Maple_files_Mat_2_Hjemmeopgave_7_igen22_MAS_1_1.mw

Original:

Hjemmeopgave_7_igen.mw

I hope some of you can solve this issue for me, as I am at a loss. Appreciate any help I can get.

This setup works, where B extends A, then B method access local variable in A directly, since it now becomes part of the object B itself

restart;
                            
module A()
  option object;
  local s::string:="";
end module;

module B()
   option object(A);
   export foo::static:=proc(_self,$)
      _self:-s := cat(_self:-s,"something");
      print(_self:-s);
   end proc:
end module;

o:=Object(B);
o:-foo()

Gives "something"

Now, I changed B, by adding an anonymous local proc() and did the same exact thing as above, which is to access s.

Now Maple complains that B does not export s

restart;

module A()
  option object;
  local s::string:="";
end module;

module B()
   option object(A);
   export foo::static:=proc(_self,$)
        proc()
            _self:-s:=cat(_self:-s,"somethig");
            print(_self:-s);
        end proc();
   end proc:
end module;

o:=Object(B);
o:-foo()

It gives

Error, (in anonymous procedure called from anonymous procedure) module `B` does not export `s`

Could someone help me understand why this happens? How it works in the first example but not in the second?  I do not see why it would make difference. isn't anonymous procedure part of the class that is being extended?

Update

It is worst than I thought. Even named local proc, inside method now fail. Here is an example

restart;

module A()
  option object;
  local s::string:="";
end module;

module B()
   option object(A);
   export foo::static:=proc(_self,$)
        local z::string:="something";
        local my_inner_proc:=proc()
            _self:-s:=cat(_self:-s,z);
        end proc();
        my_inner_proc();
   end proc:
end module;

o:=Object(B);
o:-foo()

Gives 

Error, (in anonymous procedure called from anonymous procedure) module `B` does not export `s`
I was using code which worked before, but now after extending the class, I am finding all these problems.

Is this documented something that local proc()'s inside method do not work as expected when extending classes in Maple OOP? It means now I have to move these local proc() to the outside of its current enclosing proc() to make Maple happy.  I just do not understand why this limitation.

Maple 2023.1 on Windows 10

Hi Users!

I hope everyone is fine here. I have plotted the density plot below:

restart; Digits := 20; with(LinearAlgebra); with(plots); N := 20; Mx := 20; L := 1; `&Delta;x` := L/Mx; T := 2; `&Delta;t` := T/N; for i from 0 while i <= Mx do u[i, 0] := 0 end do; for n from 0 while n <= N do u[0, n] := 0; u[Mx, n] := 0 end do; for n from 0 while n <= N-1 do for i while i <= Mx-1 do Ru[i, n] := eval((u[i, n+1]-u[i, n])/`&Delta;t` = (u[i+1, n+1]-2*u[i, n+1]+u[i-1, n+1])/`&Delta;x`^2-u[i, n+1]+.5) end do; Sol[n] := fsolve({seq(Ru[i, n], i = 1 .. Mx-1)}); assign(op(Sol[n])) end do;

Digits := 10; NP := 100; XX := [seq(seq(i1/Mx, i1 = 0 .. Mx), i2 = 0 .. N)]; TT := [seq(seq(i2, i1 = 0 .. Mx), i2 = 0 .. N)]; ZZ := [seq(seq(u[i1, i2], i2 = 0 .. N), i1 = 0 .. Mx)]; interfunc := subs(__M = Matrix(Matrix(Mx+1, N+1, ZZ), datatype = float[8]), proc (x, y) options operator, arrow; CurveFitting:-ArrayInterpolation([[`$`(i1, i1 = 0 .. Mx)], [`$`(i2, i2 = 0 .. N)]], __M, [[x], [y]], method = cubic)[1, 1] end proc); newz := CurveFitting:-ArrayInterpolation([[`$`(i1, i1 = 0 .. Mx)], [`$`(i2, i2 = 0 .. N)]], Matrix(Mx+1, N+1, ZZ, datatype = float[8]), [[seq(Mx*(i3-1)/(NP-1), i3 = 1 .. NP)], [seq(N*(i3-1)/(NP-1), i3 = 1 .. NP)]], method = cubic); nminz, nmaxz := (min, max)(newz); C := .666*(1-ImageTools:-FitIntensity(newz)); PC := PLOT(GRID(0 .. Mx, 0 .. N, newz, COLOR(HUE, C)), STYLE(PATCHNOGRID)); numcontours := 15; PP := (proc (P) options operator, arrow; (op(0, P))(op(P), ROOT(BOUNDS_X(0), BOUNDS_Y(0), BOUNDS_WIDTH(600), BOUNDS_HEIGHT(500))) end proc)(plots:-display(PC, plots:-contourplot(interfunc, 0 .. Mx, 0 .. N, thickness = 0, contours = [seq(nminz+(nmaxz-nminz)*(i3-1)/(numcontours+2-1), i3 = 1 .. numcontours+2)]), seq(plot(ZZ[1], nminz .. nminz, thickness = 15, color = COLOR(HUE, .666*(1-i3/(numcontours+1))), legend = sprintf(" %.3f", nminz+i3*(nmaxz-nminz)/(numcontours+1))), i3 = numcontours+1 .. 0, -1), legendstyle = [location = right, font = [Helvetica, 14]], font = [Helvetica, 16], labelfont = [Helvetica, bold, 16], labels = [x, t], labeldirections = [horizontal, vertical]));
plots[display](PP, size = [500, 400]);

Here the t-axis is from 0 to 20 but its actual value is from 0 to 2 and the x-axis is from 0 to 20 but its actual value is from 0 to 2. How can I change the axis? Moreover, I used the following way to extract the data in a dat file to plot the function (say f) in some professional software.

with(plots); f := plot(sin(x), x = -Pi .. Pi); dat1 := `~`[plottools:-getdata]([f]); for i while i <= 1 do A[i] := dat1[i, 3]; Y[i] := A[i][1 .. -1, 2] end do; X := A[1][1 .. -1, 1]; MM1 := `<|>`(X, `$`(Y[j2], j2 = 1 .. 1)); ExportMatrix("C:/Users/Usman/Desktop//Graph f.dat", MM1);

How I can, I extract data in the form of a dat file to plot in some professional software? 

integral of sqrt(sin(x)) is known to be as given in few place such as in here and other places.

Maple gives a result which is much more complicated (but also in terms of EllipticE special function). 

Could someone find a way to simplify it to the above answer and also to the same answer given by Mathematica?

int(sqrt(sin(x)),x)

Compare to 

Maple's result seems to be correct, as I plotted it and compared the smaller known resut. But I was not able to simplify it to obtain the smaller antiderivative.

Any tricks to do that?

Maple 2023.1 will not let me overload a method for an object when using _self.  Is there a way around this?

module person()
   option object;
   local the_name::string:="*",the_age;

   export set_info::static:= overload(
   [
      proc(_self,the_name::string,$) option overload;
          _self:-the_name:=the_name;
      end proc,

      proc(_self,the_name::string,the_age::integer, $) option overload;
          _self:-the_name:=the_name;
          _self:-the_age:=the_age;
      end proc
   ]);

   export get_name::static:=proc(_self,$)
      RETURN(_self:-the_name);
   end proc;
end module;

And now when I do 

o:=Object(person);
o:-set_info("me");
o:-set_info("me",20)

Error, (in person:-set_info) `me` does not evaluate to a module
Error, invalid input: no implementation of person:-set_info 
matches the arguments in call, 'person:-set_info("me",20)'

The problem goes away by removing `_self` as first argument in signature of the overloaded method. But then I will not be able to use _self any more inside the methods.

There is no problem overloading the method when using normal module, or one that does not use _self. For example this works

restart;

module person() 
   export set_info:= overload(
   [
      proc(the_name::string,$) option overload;
          print(the_name);
      end proc,

      proc(the_name::string,the_age::integer, $) option overload;
          print(the_name);
          print(the_age);
      end proc
   ]);
end module;

person:-set_info("me");
person:-set_info("me",20)

How to make the first example above work? I need to overload a method inside an module with option object that uses _self

update

I found a workaround. But it is not good, but for now. For the overloaded method, instead of using 
           o:-set_info("me");

This works instead

         set_info(o,"me");

So the following now works

o:=Object(person);

#o:-set_info("me");   #do not use with overloaded
#o:-set_info("me",20); #do not use with overloaded

set_info(o,"me");  #now works OK with no error
set_info(o,"me",20); #now works OK with no error

o:-get_name();  #OK since this method  is not overloaded
o:-get_age();  #OK since this method  is not overloaded

I do not understand why _self can't be used with overloaded methods and if this a bug or by design. 

Maple 2023.1 on windows 10

Download self_with_overloaded.mw

In short, I'd like to obtain n largest/smallest elements in a huge list of (probably non-numeric) data. Of cource I can sort it and then extract the desired part, yet isn't there a dedicated procedure that do a partial sort of the input data in Maple?

Edit. In a MatLab weblog, the blogger gave: 

So I believe that a dedicated one is not useless. But what is the Maple equivalent to MatLab's maxk, mink, and topkrows?

If if solve for two circles intersecting the general solution conteint a factor of (xc1-xc2) i.e. x co-ors of the circle centres in both numerator and denominator. So the solution fails if they are equal i.e circles vertically aligned.
I can get arount the problem using  "RealDomain" but that introduces Signum which I dont like and is much slower to solve. I substitued out substitued signum out signum(xc1-xc2)=1. Works.

Just looking for is neater solution approach.
 

Download 28-10-28_Q_Circles_Intersect.mw

It seems like my maple document has been corrupted. When I tri to open the document I'm met with an error message "There were problems during the loading process. Your worksheet may be incomplete."

I have spent a great amount of time in this document, so if there was a way to recover it, that would be fantastic.

Thanks!

Download prac_exam_ece4179.mw

Hi

Why, when I run the integral command, it only prints the integral instead of solving it?

Hi, I'm looking to create a series of random exercises on square roots for my students with two objectives: Simplify square roots and rationalize the denominator. Here's my scenario: I'm using the properties of the table to display the question and its solution, and generate a PDF with a good layout. I have two issues with the code: I don't want to display the '*' symbol when using "Parse" for "ex1" and "ex2," and I want only one denominator to be displayed for "Sol2." Thank you very much for your insights

AléatoireSérieRadicauxTEST.mw

TestRacineCarrée.pdf

Hi all

I need your advice on Maple usage after a long break. I installed Maple on my laptop and first of all tried to launch my old program. Surprisingly, the old file opened. While the core Maple functionality remained familiar, the user interface had undergone some changes.

Yet, I soon encountered challenges when attempting to perform even the simplest operations, like file browsing or text selection; the Maple Standard GUI seemed uncharacteristically sluggish.  I switched to Maple Input mode but it didn't help much. Are there ways to improve my experience with Maple? Is it caused by the outdated hardware?

My system:
Ubuntu 22.04.3 LTS
Dell Inc. Latitude 5510 (1TB SSD, 32GB RAM).

Maybe it works much better on Windows?

Thank you for any suggestions.

How do I compile a larger maple code for usage without maple system ?

Thanks for support :)

I am trying to separate a value by using solve common but could get the answer. Is there any way to get required expression

Simplification_Help.mw