@Thomas Richard 

Is there study on which platform Maple is more reliable? mac or Linux or windows?

For me, on windows (now windows 10), I can get Maple to easily hang/freeze/crash few time every day. 

All what I have to do is run my program which takes 20 or more hrs to complete, and it will either crash or most likely hang at random location each time then I have to kill mserver.exe and restart worksheeet again from the same spot it was hanging, It is these random hangs where mserver will stay running at high CPU no matter how long I wait. So I keep checking every 1-2 hrs, and when I noticed this, the only option is to terminate and start again at same problem it was hanging. Then it works. seems like memory or such problem. I never figured why this happens.

Then it runs again OK for 2-3 hrs and then the same problem happens at different random place.  Nothing improves. Same problems I had for years. version after version.

If Maple on mac or Linux are known to be more reliable, I will switch and try. I never used Maple on anything other than windows.

As I was typing the above, Maple mserver.exe went into one of its spins. Been running like this for one hr now.  I can leave it running for 5 years and it will still be doing same thing.

Here is movie. So I had to kill it and start again at same problem and it ran OK. So it is not my program. If it was my code, then it will do the same thing again at same location, but it does not.

@Carl Love 

fyi, sometimes this does not work. Here is example

f:=-(8*x*y^(5/3)+y)/x/(2*x*y^(2/3)-1);
L:=discont(evalc(f),x);
indets(L[2],suffixed(_Z));
indets(L[2],suffixed(_));
has(L[2],_Z)

Maple 2023.2.1

@sand15 

You can try this. Make sure you end your printf(...) with "\n"  this sometimes causes the line buffer to automatically flush and not be buffered.

can you make a small example showing this problem?

@Carl Love 

You used nops()? But for Vector it should be numelems

@Carl Love 

That is really very strange. For me, it said update available. 

I was also running 2023.2 before.

The update went smooth like always. Other than the version number not changing.

@Carl Love 

Why download the update?  The way I always update is like this:

Open Maple and do

                   Tools->Check for Update

If there is an update, it will say so. Then clicked Update.  At one point it will ask you to close Maple in order to finish the update. After closing Maple, it will now finish. 

Now open Maple, and check the version, it should say the new version.

But in this case, the version number was not changed. Which is why I asked above. It should have changed.

windows 10.

I just installed the update. When I start Maple again it still says  2023.2 

I was expecting it to say 2023.2.1

How does one know for sure they are running 2023.2.1 if the version number still says 2023.2? Is there a different command than the above to use that will display 2023.2.1 ?

interface(version)
    Standard Worksheet Interface, Maple 2023.2, Windows 10, 

       November 24 2023 Build ID 1762575


version()
 User Interface: 1762575
         Kernel: 1762575
        Library: 1762575

                            1762575

How did you generate the bode plot? You need transfer function to generate bode plot?

restart: 
alias(DS=DynamicSystems): 
sys:=DS:-TransferFunction(5*s/(s^2+4*s+25)): 
DS:-BodePlot(sys,output=dualaxis, range=0.1..100);

so you already has the TS. Even if you have state space, you can convert that to TF.

how to find CharacteristicPolynomiall of matrix with vector entries?

I do not understand what the issue is. Why not just do something like

V1:=Vector[column]([1,2,3]);
V2:=Vector[column]([4,7,9]);
V3:=Vector[column]([99,8,11]);
M:=Matrix([V1,V2,V3]);
LinearAlgebra:-CharacteristicPolynomial(M,x)

It works for me on Maple 2023.2

@Christian Wolinski 

I am interested to learn how  then you interpret the help page saying

    "It will do the simultaneous substitutions specified by the eqi equation arguments in the last argument expr"

Would that not imply all substitutions are done in place and at same time on the original expression? This is how I read it.

Ofcourse, the help page could be wrong and internally it does as you described. I do not know.

@Carl Love 

opps, you are right. I forgot this rule. So maple's Math is the correct one.  I need to go have more coeffee.

@Christian Wolinski 

I thought that is what it did, this is why I asked if order matters. But that would be really wrong design if this was the case. Also help says

And dictionary says  that simultaneous means:  occurring, operating, or done at the same time.

So it should be doing the substitution in "batch mode", ie, at same time. Not do one. Evaluate the new expression, and now do the next replacement on the new expression, which ofcourse could now have changed, reshuffled, order of operands might change, number of operands changed, and so on. This design would make no sense from the user point of view if this was the case, right?

But who knows. May be help is wrong and may be it works as you said.

fyi, this gives zero

VectorCalculus:-Laplacian(1/r, 'spherical'[r,phi,theta] )

                         0

@Preben Alsholm 

Thanks. But I am little confused what is the bottom line here. Is this a bug in has?

But if one wants to write a function that takes in P, where P is the plot generated by DEplot, and return true of false depending if the plot is empty or not, then what will this function looks like based on what you found above?