## losing connection to the maple kernel...

Why would firewalls cause issues with connecting to the maple kernel if the CAS is entirely self contained (as ive been told before on this forum)

## Optimization with LPSolve (Kernel Crash!)...

Example 6 from Maple Help.

restart:

with(Optimization):

LPSolve(2*x+5*y, {3*x-y = 1, x-y <= 5}, assume = {integer, nonnegative})

Kernel crash the same with Maple 2015.

`Does anyone can confirm?Mariusz Iwaniuk`

## Kernel does not work...

Dear all

When may program begin the following massage appears

kerenl connectio has been lost

## Kernel of a map between two polynomial rings...

Assume we have a map f from a polynomial ring R to another polynomial ring S, I know how to compute kernel (a generator for the kernel ideal) of these maps by Singular, but I want to know can I do it with Maple too? Thanks.

An example;

Consider the homomorphism f:k[x,y]-->k[u,v] sending x to v and y to v^2 then using Singular;

ring r1=0,(x,y),lp;

ring r2=0,(u,v),lp;

ideal i=v,v2;

map f=r1,i;

setring r1;

kernel(r2,f);

_[1]=x2-y

So at above I took k a field of characteristic zero. The kernel is the ideal generated by x^2-y.

## Source of TRDpolynomial_ring...

I am not seeing any reference in help to TRDPolynomial_ring in PolynomialRing function in RegularChains. Though if I debug it, I can get in it. Is it that it is part of kernel ?

## Problem with integer optimization...

When I use the option assume = nonnegint or integervariables = {...} in Optimization[Minimize], or Optimization[LPSolve] I've got the message "kernel connection lost'.

Thie even happens when I use the simple example from the Maple help:

with(Optimization):
LPSolve(2*x+5*y,{3*x-y=1,x-y<=5},assume={nonnegative,integer});

It says; mserver.exe has stopped working.

What's wrong?

## Lost data in worksheet...

While I am working with a problem , suddenly the message 'Kernel connection lost' appeared. After that I restarted maple and then I opened my work sheet again , but I lost all my equations and data in the work sheet. I dont know why? All my work is total empty.

How can I recover the work sheet data? Solutions are appreciated.

I have attached the lost work sheet for your reference.

Thanking you.

## Kernel connection lost...

Hello,

I'm trying to calculate and export a huge "Strategy-Matrix". The calculation works in a smaller version with less possible strategies. For this version I use a specialised simulation-PC with enough memory (that was my problem using my own PC). But now I've got this error massage ("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. Please ensure that any firewall software is configured to allow Maple to create connections to the kernel. Consult the FAQ for more information.")

The firewall should not be the problem. Below the code. num_Strat is 63001.

m_Gi:= Matrix(num_Strat, num_Strat):

for t from 1 by 1 to num_Strat
do
Digits:= 5:
v_h2:= evalf((-(24/17)* v_pEi[t]^2)*v_h1 + (v_pEi[t]*(-(128/51)*v_pKi[t]+980/51))*v_h1+ v_pEi[t]*((40/51)*v_pKj+(15/17)*v_pEj)-((110/51)*v_pKi[t]^2)*v_h1 + v_pKi[t]*((55/51)*v_pKj+1220/51*v_h1+(10/17)*v_pEj)):
m_Gi(..,t):= v_h2:
end do:
ExportMatrix(TestMatrixNK, m_Gi):

## sandboxing an operation?...

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.)

## Error, (in rtable/Power) singular matrix...

Hi,

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

Matrix_Fred:=proc(N,d,lambda)
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;
Fredholm:=phi(x)=f(x)+lambda*int(Kernel(x,y)*phi(y),y=-a..a);
Kernel:=(x,y)->ln(abs(x-y));
eq2:=int(Kernel(x,y)*phi(y),y=-a..a)=sum(int(Kernel(x,y)*phi(y),y=n*h..(n+d)*h),n=-N..N-d);
Vct_basis:=[seq(x^i,i=0..d+1)];
fct:=[seq(unapply('Vct_basis[i]','x'),i=1..d+2)];
sys:=[seq(eq3(fct[i]),i=1..d+1)];
w := [seq(beta[i,n],i=1..d+1)];
M,b := GenerateMatrix(sys,w);
M1:=-M; V:=-b;
Vect_beta:=(M1)^(-1).V;
for i from 1 to d+1 do
beta[i,n]:=Vect_beta[i];
end do;
x:=m*h;
for i from 1 to d+1 do
alpha[m,n,i]:=unapply(beta[i,n],n,m);
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)];
Fredholm_stencil:=subs(Subs1,eq6):
Stencil[1] := unapply(Fredholm_stencil,m,lambda,phi,f);
sys1 := [seq(Stencil[1](m,lambda,phi,f),m=-N..N)]:
sys2:=subs(Subs1,sys1):
Subs2:=[seq(f(m*h)=f[m], m=-N..N)]:
sys3:=subs(Subs2,sys2):
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;
Matrix_Fred(N,d,lambda);
1
2
3
--
Pi
Error, (in rtable/Power) singular matrix

## How to deal with formal parameters in linear syste...

Hi,

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,

NoThik

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

## Can anyone explain this "kernel" error message fro...

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.

NewPicture.mw

GS

## Kernel connection lost in Linux X64 but not in Win...

Hi,

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".

## Very special evaluation rules of `if`...

In the following code, why is B returned unevaluated?

`restart:A:= a:  B:= 2:F:= _a-> eval(`if`(A,B,C), a= _a):F(true);                               Beval(B);                   ...`

## execution stopped:......, the kernel has been shut...

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

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