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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.)

Hello, Maple wizards.

I have a problem with Tasks for parallel computations. In each task my programm should execute this command:


"A" and "B" are Arrays (1..m). "m" is integer. I have 8 tasks. Each task is a loop ("for i from 1 to n do..." n is integer), where my command is executing. "A" and "B" are local for each task. In this case each task should execute my command n times.

So, I obtain this:

"Error, (in SignalProcessing:-Engine:-DFT) attempting to assign to `FwdDFT` which is protected"

What is it? In Maple Help I read that ">SignalProcessing:-DFT" is Thread-Safe Function.


I really need help!
please help to solve the boundary value problem by method of shooting.
I never met with this problem and I can not quite figure out how to solve this problem in maple
Thanks for the help!

 the problem

This post is an index page for reading the Parallel Programming blog posts.

Hello, everyone. I have some problem with multithreaded calculation. I just need calculate eigenvalues of matrix m at various parameters (and then export to a file) using advantages of the parallelizing. The following code works but in serial way


restart: with(LinearAlgebra):

m:=ImportMatrix(cat(currentdir(),"m.txt")): # here is matrix m.txt




local u,i,j,nmc:



for i from 2 to op([1,1],u) do


end do:

for i from 1 to op([1,1],u) do

nmc:=sort(Eigenvalues(m*u[i,1], output='list')):

for j from 2 to op([1,2],u) do


end do:

writedata[APPEND](cat(currentdir(),"u_",convert(k2,string),".txt"), [convert(Re(u[i]),list)]):


end do:

return finished:

end proc:



Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]);



The Start(ArrayTools[Concatenate], 2, Task=[prc,1,20], Task=[prc,20+step,40]) function makes two tasks of calculation at the parameter ranges of 1-20 and 21-40. But in this case Start spends twice more time than simply prc(20+step,40). How to realize a multithreaded calculation?

By the way I don't need to use a Concatenate function in Start but without any procedure Start doesn't work.

I have a statistics task that is very complicated to me, and I would really appretiate some help!

I believe that I have completed task a, but task b and c seems to be too hard for me to grasp.

Here is a presentation of the task text:


xi 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
yi 12.3 12.8 16.8 17.9 20.5 22.7 24.9 27.5 26.9 29.4 30.3 34.2 36.4 36.7 41.1

Assume that the data represents independent realizations of a "linearlnormal" model.

Yi = α + β xi + ei i = 1..15,

where ei˜N(0,σ), where sigma is unknown.


(a) create a scatterplot of the data {f(xi,yi)}15 ; i=1
Then calculate the empiric correlation coefficient.

(b) Find the minimum least square estimate for α & β.

(c) Create a 95% confidence interval for the parameter β. What does this confidence interval express?

Is there anyone out there who are able to help me with some maplecode?

thanks in advance,


This blog post is a response to a post on MaplePrimes.  MaplePrimes user wkehowski asked how the Task Model could be used to filter combinations.  The basic problem is formalated like this:  We want a function, I'll call it FilterComb, that accepts positive integers...

In the following task procedure, when i>1, it works well,but if i=1, the task(M,1,5) returns error


I am planning to use the "schedual task" in windows to try to launch
maple in the background (run under some different user account)
to do some computations.

For this pupose I have designed a little counter that is located in the
Start up code region:

for i from 0 to 100 do
if DataTable1(1, 1)=i then DataTable1(1,1):=i+1:  break; end if:
end do:

the DataTale will tell me how many times the worksheet has been opened
just to check...

Is there a way to plot a function in a multithreaded way?

I have a computing-intensive function (eg. integral over Hermitian-Polynoms), which I want to plot. I couldn't find a way to do this such, that all my cpu-cores are used.

Any suggestions?


Hello, MaplePrimes!

I want to create a custom component to model dynamics of a movable pulley, which can rotate and move along some direction (translational motion). I’ve got dynamic system, which describes both motions of a pulley. Some information about this dynamic system:


I want to download historical data from google finance for two Indecies simultaneous
but I dont understand where the output is saved...?!  Also should I use task or threads ?


X1 := proc () local str, sid; global b; str := "";

sid := Open("", 80);
Write(sid, cat("GET /finance/historical?q=INDEXSP:.INX&histperiod=daily HTTP/1.0 \n\n"));

b := Read(sid); while b <> false do str := cat(str, b...

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