MaplePrimes - Maple 2020 Posts and Questions

Why is Threads:-Task:-Continue miscomputing?

RafalAblamowicz — Fri, 30 Jan 2026 06:53:17 Z

Hi,
I am experimenting with Threads:-Task:-Continue in Maple 2020.2 and sometimes it returns different results depending on N, or, how fine the mesh is. I have modified procedures cont and task in a Maple example shown in a worksheet. I can compare the result from Threads with one I can obtain another way and which surely is correct. The result from Threads depends on N: sometimes it is correct, sometimes it is not. The wrong result is returned only when the Threads:-Task:-Continue loop is executed, of course.

Has anyone spotted that problem? Is there a way to trace what actually is being done in each leaf? Does this problem appear in later versions of Maple?

I would appreciate some feedback.

Thanks in advance,

Rafal Anlamowicz
rablamowicz@gmail.com

Help with the Solution Steps?

delvin — Wed, 12 Mar 2025 12:33:55 Z

Hi,

In order to obtain an algebraic system, one must set the coeffcients of (H + G′/G2)i to zero. Solve the obtained algebraic system.

But the expressions were not arranged correctly, but no answer was obtained, while the answer was as follows:

restart

>	with(PDEtools): df:= diff(diff(G(xi), xi)/(G(xi)^2), xi)= A+B(diff(G(xi), xi)/(G(xi)^2))^2+ c(diff(G(xi), xi)/(G(xi)^2));

(1)

>	a := [a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10]:

>	p:= -2: q:= 2:

>	Y1 :=xi -> (add(a[i+3]*(H+(diff(G(xi), xi)/(G(xi)^2)))^i, i = p .. q)):

>	eq1 := -4(k^2)mdiff(Y1(xi), xi,xi) - 4l(Y1(xi)^2)+(4(nu^2)-4nun+n^2-4)*Y1(xi):

>	eq2:=subs(df,eq1);

(2)

>	simplify(eq2):

>	fin1:=simplify(numer(%)):

>	for i from 0 to degree(fin1,H+(diff(G(xi), xi)/(G(xi)^2))) do EQ[i]:=simplify(coeff(fin1,H+(diff(G(xi), xi)/(G(xi)^2)),i)); end do;

(3)

>	for i from 0 to degree(fin1,H+(diff(G(xi), xi)/(G(xi)^2))) do EQ[i]:=simplify(coeff(fin1,H+(diff(G(xi), xi)/(G(xi)^2)),i)); end do;

(4)

>	Eqs:={seq(EQ[i],i=0..12)}:

>	sol:=solve(Eqs,{a0, a1, a2, a3, a4, H, nu},explicit)

(5)

Download GGGGGGG2.mw

Help with problems solving?

delvin — Fri, 07 Feb 2025 07:54:08 Z

Hello

I encountered a few problems. One is that in the first section, I wanted to use the definition above instead of f (s ) and g (s ), which means that when the variable changes under the integral sign, it should detect and replace it.

And the next is that in the Equality section, I should sort by p and set the coefficients to zero. And then, for example, solve for the zero power of p and get the value of f0 and use it in subsequent solutions. Can you help me?

>	restart; equ1:=diff(f(t),t)-1-t-t^2-g(t)-int(f(s)+g(s),s=0..t)=0; equ2:=diff(g(t),t)+1+t-f(t)+int(f(s)-g(s),s=0..t)=0;

(1)

>	f(t):=sum(f[i](t)*p^i,i=0..1);

(2)

>	g(t):=sum(g[i](t)*p^i,i=0..1);

(3)

>	hpm1:=(1-p)(diff(f(t),t)-1-t-t^2)+p(-diff(f(t),t)+1+t+t^2-g(t)-int(f(s)+g(s),s=0..t))=0; hpm2:=(1-p)(diff(g(t),t)+1+t)+p(diff(g(t),t)-1-t+f(t)-int(f(s)-g(s),s=0..t))=0;

(4)

>	A:=collect(hpm1,p);

(5)

>	for i from 0 to degree(A,p) do EQ[i]:=simplify(coeff(A,p,i)); end do;

Error, final value in for loop must be numeric or character

Download HPMsystem.mw

Can this theorem by proved?

Earl — Fri, 17 Jan 2025 17:56:28 Z

Problem Q15 in the book Parabolic Problems by David Angell and Thomas Britz describes a large circle (LC) and several smaller circles (SCs) which are each tangent to its neighbour SC(s), and externally to LC. All circles are tangent to the x axis and above it.

Section one of this worksheet displays the LC and six of the SCs based on the book's formula for the diameter of the latter in terms of the diameter of the LC and the largest SC, which is determined by the user.

Section two finds and displays that all of the displayed SCs' centers lie on the diameter of a circle closely related to the LC and larger than it.

Can this be proved to be the case for any sizes of the LC and SCs in the same formation as that displayed?

Parabola_Problems_Q15.mw

What is the correct way to solve these two problems?

Earl — Tue, 14 Jan 2025 20:05:00 Z

This worksheet defines two physics problems and fails in the attempt to solve the first one.

How can these problems be solved?

Rolling_circle.mw

Optimal solution for schedule?

brian bovril — Thu, 09 Jan 2025 13:45:41 Z

Hello

Following on from my earlier question:

https://www.mapleprimes.com/questions/239620-Round-Robin-With-Double-Bye

a colleague has produced (admittedly hurriedly) a sports schedule over 14 weeks for a 8-team double bye, and a 10-team over 15 weeks.
Looking at it, and counting the possible combinations, neither seem optimal...

The 8 team has equal byes, the 10 uneven.

Edit. Ideally no team would have 2 byes in a row.

Is there a solution in maple over these weeks? given the min duration would be 13 weeks and the max 15 weeks?
In the previous solution by mmcdara the 8 bye schedule each team has played 6 times after week 8, but since the roster is truncated to 14 or 15, there will be some weeks when no byes are required (all teams playing) to even things up.
Similarly, the 10 bye each team has played 8 times after week 10, but since the roster is truncated to 14 or 15, there will be some weeks when no byes are required.

Any help would be welcome!
double_bye.xls

Edit: I made some counting errors. It's 28 and 45 as Carl pointed out
double_bye_revised.xls