Since approximately a week ago, probably after some Ubuntu update, the xmaple 2021.2 interface started to crash after some simple commands, without any error message or log. I tried to run with java (open-jdk) 11 and 8, and I had the same problem. I still have an old 2017.3 version, and it works perfectly. The problem only affects the new Maple release. 

Is there some bug report? What can I do?

I'm a newbie to maple, I want to get a group that meeting the criteria with this code:

with(GroupTheory);
G := SymmetricGroup(6);

do

H := Subgroup({RandomElement(G),RandomElement(G)}, G);

C := Core(H, G);

until is(GroupOrder(C) <> 1) and is(GroupOrder(C) <> GroupOrder(H));
H;
C;

But it's seem I cannot construct subgroup. so I adjust it into:

with(GroupTheory);
G := SymmetricGroup(6);

do

H := Subgroup({[[rand(1 .. 6)]], [[rand(1 .. 6), rand(1 .. 6)], [rand(1 .. 6), rand(1 .. 6)]]}, G);

C := Core(H, G);

until is(GroupOrder(C) <> 1) and is(GroupOrder(C) <> GroupOrder(H));
H;
C;

However, it is clear that random numbers do not always satisfy the rules of permutation. So how can I use the loop to generate a random subgroup that satisfies the condition?

How to adapt this program C to Maple ? Thank you.

Sub Les_Vendredi_13()
Dim Annee As Integer
Dim Mois As Byte
Dim Cellule As String
Dim Compteur As Byte
Cellule = "B2"
Compteur = 1
Columns("B:B")
.ClearContents For Annee = 1949 To 2009
For Mois = 1 To 12 If Weekday(Mois & "/13/" & Annee) = 6
Then Range(Cellule).Offset(Compteur, 0) = "13-" & Format(Mois, "00") & "-" & Annee Compteur = Compteur + 1 End
If Next Mois Next Annee Range(Cellule).Offset(Compteur, 0) = "Nbre = " & Compteur - 1
End Sub

Hello!

I'd like to sort variables which are non-commutative and obey certain commuting rules in a preferred order. Here is a minimal example

with(Physics)

Setup(mathematicalnotation = true):Setup(noncommutativeprefix = {q, w}, algebrarule = {%Commutator(q, w) = A})

If I want to rewrite q*w as A+w*q since I prefer the order w>q, what should I do? I tried sort(Simplify(q*w, algebrarules), [w, q]) but it doesn't work.

Thank you in advance.

The long form of ScientificConstants[GetValue] is not working in at least Maple 2021 and Maple 2022

ScientificConstants[GetValue](Constant(g))

This is causing issues for MapleFlow, not being able to call on a constant. 

**edit some of the long forms work - specifically the GetValue does not.  I modified the title to reflect that.**

with(GroupTheory);
G := GaloisGroup(x^5 + 20*x + 32, x);

I just can get a result like:

GroupTheory:-GaloisGroup(x^5 + 20*x + 32, x)

But how do I know exactly what group it is? Actually I know the galois group is D₅, But can we use maple to get this information?

ds := DerivedSeries(PermutationGroup({[[2, 3, 5, 4]], [[1, 2, 3, 4, 5]]}))

will get a series group like:

How to get the group by the red line point out? Then I can use GroupOrder to get the order of it. I note GroupOrder[ds[2]] don't work

I have a student who then she uses tools/assistent/import data and then the file then Maple claims the Excel file is empty? She uses Maple 2021.2. File works on other my and other student computers. 

I have two questions:

1) How can I select only parts of an equation in a Maple Workbook? E.g. I have

4*x^2*(1 + x)^2*(x^2 + 6*x + 1)

and I want to select the text between the first "2" and the "6", but Maple always extends the selection to include the complete bracket. This is very annoying :)

2) How can I copy text from a maplesoft page into a workbook. E.g. I'm looking at

https://www.maplesoft.com/support/help/maple/view.aspx?path=updates/Maple2021/ODEsandPDEs

and I would like to select and copy some of the shown examples so that I can use them.

Suppose I want to calculate gcd(g(x),f(x))=a(x)f(x)+b(x)g(x) for two polynomial, i.e finding the RHS representation of the gcd, then how to implement this in maple?

I know of the command GCD(f(x),g(x)) but how to find the RHS representation?

Thanks!

primes_integrale_exp.mwThe integral in x of 

exp(-sqrt(x^2 + c))

was done by Maple 11 but return unevaluated in Maple 2021,

see attached worksheet 

I am trying to solve the equation in the attached Maple file, but Maple cannot return a result.

Download test_fsolve_integ.mw

I try to sove the equation x^2-10*y^2=9 with tne procedure : 
genpellsolve := proc(D::posint, N::integer)
local t, u, L1, L2, sols, x, y;
if type(sqrt(D), integer) then error "D must be a nonsquare integer"; end
if; t, u := pellsolve(D); if 0 < N then L1 := 0;
L2 := floor(sqrt(1/2*N*(t - 1)/D)); elif N < 0 then L1 := ceil(sqrt(-N/D));
L2 := floor(sqrt(-1/2*N*(t + 1)/D)); else return {[0, 0]}; end if;
sols := {}; for y from L1 to L2 do x := sqrt(N + D*y^2);
if type(x, integer) then sols := sols union {[x, y]};
if (x^2 + D*y^2) mod N <> 0 or (2*x*y) mod N <> 0 then sols := sols union {[-x, y]};
end if;
end if;
end do;  return sols;
end proc:
This procedudure fails; I don't see why. Thank you for your help.

I run Maple 2021 under Ubuntu 20.04 on a new Lenovo laptop with 32Gb of Ram. Every time I start Maple, it runs for a few minutes and then loses the "kernel connection". I have to save the worksheet and re-start Maple. In dmesg, I find:

[ 1436.724570] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-1000.slice/user@1000.service,task=mserver,pid=8037,uid=1000
[ 1436.724589] Out of memory: Killed process 8037 (mserver) total-vm:31723552kB, anon-rss:31289772kB, file-rss:60kB, shmem-rss:0kB, UID:1000 pgtables:61656kB oom_score_adj:0
[ 1437.151441] oom_reaper: reaped process 8037 (mserver), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

indicating that Maple's virtual memory exceeded 30 Gb! This happens even if the only command I execute is, for instance, "resrart" or "A:=1" and nothing else. It also happens when no other applications are running and the "top" command indicates that around 30Gb of RAM is available.

In this state, Maple is utterly useless to me. This was a new install of Maple and a fresh install of Ubuntu on a new laptop, surely I am not the only one seeing this?

I have tried setting a 30Gb limit in "kerneloptions" for "stacklimit" but that di not make a difference.

If you have seen any behaviour like this, please respond. Is there some bug in Maple that leads to oncontrolled and unprovoked memory grabbing?

Dear all,

I'm using Maple to calculate the geodesics of the Poincare' Half Plane:

restart:
with(LinearAlgebra): with(DifferentialGeometry): with(Tensor): with(Tools): with(plots): 
DGsetup([x,y],M1)
g1 := evalDG(1/y^2*(dx &t dx+dy &t dy))
R1 := CurvatureTensor(g1)
K := SectionalCurvature(g1,R1,D_x,D_y)
Gamma := Christoffel(g1)
C := [x(t), y(t)]
V := GeodesicEquations(C, Gamma, t)
DE := Tools:-DGinfo(V, "CoefficientSet")

simplify(dsolve(DE, explicit))

I receive this error message

Error, (in simplify/siderels:-simplify/siderels) specified variables must be names or functions

How can I fix this error?

Thanks, Nicola