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I am working with a package that is not entirely stable and which can sometimes corrupt Maple's state. I would like to "sandbox" the risky operations, executing each of them in another kernel thread that I can destroy (or somehow reset), getting back just the return result of each operation (each return result involves only global names, numbers, and strings). What would be a good way to achieve this?

I see the Task model, but it is not clear to me that each kernel used is effectively restart()'d for each Task Start(). At the moment I would have a bit more confidence in manually using Thread Create(), except that I do not see any information on how to destroy a thread (just to destroy Mutex and Condition Variable resources.)

This is, I suppose, a kind of security, but it is not covered by EngineSecurity. (Not unless I need to process[popen] to achieve this.)

I was calculating average BER for BPSK and while its execution encountered kernel failure with an error message as "execution stopped:stack limit reached.worksheet lost connection to should save worksheet and restart maple."

how to overcome this error. Any help?


I have an error how can I fix the error. Thank you.

local Kernel,K,Fredholm,phi,MatA,eq2,eq3,eq4,Vct_basis,fct,sys,M,b,M1,Vect_beta,W,i,beta,alpha,eq5,eq6,x,Subs1,Fredholm_stencil,Stencil,w,V,sys1,sys2,Subs2,sys3,Sol_phi;
w := [seq(beta[i,n],i=1..d+1)];
M,b := GenerateMatrix(sys,w);
M1:=-M; V:=-b;
for i from 1 to d+1 do
end do;
for i from 1 to d+1 do
end do;
eq5:=lhs(eq2)=sum(rhs(eq4), n=-N..N-d);
eq6:=subs(x=m*h,subs(lhs(eq5)=rhs(eq5) ,Fredholm)):
Subs1 :=[seq(phi(m*h)=phi[m], m=-N..N)];
Stencil[1] := unapply(Fredholm_stencil,m,lambda,phi,f);
sys1 := [seq(Stencil[1](m,lambda,phi,f),m=-N..N)]:
Subs2:=[seq(f(m*h)=f[m], m=-N..N)]:
Sol_phi := [seq(phi[i],i=-N..N)]; # The unknown vector must be computed.
MatA := GenerateMatrix(convert(sys3,list),Sol_phi)[1];
return MatA;
end proc:

d:=1; N:=2; lambda:=3/Pi;
Error, (in rtable/Power) singular matrix


I want to compute a formula which is too complicated and it contains some variables. So I divide it into several parts. But it always turns out kernel connection has been lost. I looked maplesoft online help system and change the ConnectionType from 0 to 2. But it does not work. So how does this happen and how to solve?

I attach my maple file which appears error.
Thanks a lot!




I have a Matrix whose entries are polynomials in several formal parameters (the matrix is sparse and the polynomials are rather simple, though inverses of the parameters may also arise).
Then, when I compute the kernel with LinearAlgebra-NullSpace, maple naturally gives a basis of solutions over the same ring of polynomials.

Now for some reason there are some parameters that I don't want to see in the solutions (all but two of them, actually).

How can I compute the part of the kernel that lives in $\mathbb{Z}[a,a^{-1}, b,b^{-1}]$, i.e. that involves only the first two parameters?

Thank you,


Edit : the coefficients of the polynomials are integers, and I expect the kernel elements to have integer coefficients as well.

I am having trouble getting a certain Maple worksheet to execute.  Using both Maple17 (I think it is 17.02) installed on two separate PC's at home (XP), and using Maple15 via Citrix from a server maintained by my employer, I get a long error message.  It starts:    "Kernel connection has been lost.  You should save this worksheet and restart Maple.  Executing commands in Maple requires a connection to the Maple kernel.  Firewalls have been known to cause problems with kernel connections in Maple.".  If anyone wants, I can add the entire error message to this question. I don't think I actually have a firewall at home, and this error message doesn't seem to explain why my local copy of Maple is having trouble.

I think I updated my home copy of Maple to Maple 17.02 after I started writing the worksheet and before this problem appeared, so there may be an issue with Maple 17.02.  But this would not seem to explain the trouble I have executing the worksheet using Maple15 via Citrix.

I have uploaded the file.  I removed the output to make it a reasonable length.  I created a "toy" file that plots x^2 from x = 1 to x = 4, and does nothing else, and it works just fine.  I apologize for the length of the file I uploaded, but I don't know exactly what is causing  the error.





I have always been experiencing problems using a university server. It runs Red Hat 6.4 (Santiago) and Maple 17 X64.

The problem never occurs on Windows 7 SP1 X64 with Maple 17 X64.

Only reason I want to use the university machines is that it's "faster".

I had raised...

In the following code, why is B returned unevaluated?

A:= a:  B:= 2:
F:= _a-> eval(`if`(A,B,C), a= _a):

hi guys,i have a program when i run it after 3or4 minutes maple give this :

execution stopped:memory allocation failed.please see ?alloc for more detail.

when i ok it then give this :

the kernel has been shut down.further computations cannot be performed.


what do you think ?



thank you very much

What are the main functions of the kernel Male and for which they are responsible?

Hi all,

I am running xmaple via linux, version 17.

This is on a Unbuntu OS X64 with i7 940X, and 4G RAM.



My query has spawned two new questions.

1) Why won't this work?

  First embed and Text area component TextArea0

  I thought the contents of the procedure would be entered into TextArea0.

2) While code is being evaluated in Maple, is it possible to continue working within the same kernel?  or must one have to be in a separate Maple (kernel) window?

above link's comment said eliminate will NOT generate a polynomial in all cases

make me think that eliminate in above link can not return correct one.

what is the correct way to convert groebner basis of kernel into kernel?

the goal is to check kernel belong to image in Maple

K := {r-x^4,u-(x^3)*y,v-x*y^3,w-y^4};
G := Basis(K, 'tord', degrevlex(r,u,v,w));
R1 := eliminate(G, {r,u,v,w}); # eliminate is the reverse of Basis
Ga := Basis({a*G[1],a*G[2],a*G[3],a*G[4],a*G[5],a*G[6],a*G[7],a*G[8],a*G[9],a*G[10],a*G[11],a*G[12],a*G[13],a*G[14], (1-a)*K[1], (1-a)*K[2], (1-a)*K[3], (1-a)*K[4]}, 'tord', deglex(a,r,u,v,w));
Ga := remove(has, Ga, [x,y,a]);

below code is calculate basis of kernel and kernel

i guess basis of image is 

remove(has, Ga, [r,u,v,w]); if this correct, i eliminate this, i can get the image
however it include variable 'a'
is it correct? if not, how to calculate? 
my final goal is to make unexact sequence into exact sequence
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