sometimes, the maple server goes in a loop and runs full CPU. Waiting makes no difference. It just hanged. Even stopping the computation from the UI makes no difference (i.e. cliking on the "interrupt the current evaluation" button). Only way I found is go to task manager and terminate the mserver.exe by force.

The problem now is that I have to close Maple and start all over again. Since I can't start a new computation or do anything if the server is down.

I am just asking if there is a better way to do all this. For illustration, this int() command below hangs the server, so you can try the same thing I am seeing. This is on Maple 18.02, windows 7, 64 bit.

Make sure to save all your work before running this. This is just one example. I have many more where maple hangs like this (i.e. the interrupt does not terminate anything and the server keeps running)

y := 1;
z := 2 + x + y;
s := 1/2;
m2 := 5325;
m1 := 5279;
mz := 106055/10;

int1 =evalf(int(1/z^3 *(x + y + 2* x*y)* (1 + s^2/(2 *m2^2* z)) *exp(-(m2^2*x + m1^2*y)/s^2 + (mz^2 *(x + y + 2 *x*y))/(2* s^2* z)), x=0..1));

After I do

restart;
plot(cos);

Now I right-click on the plot, and from the menu change the "line" to "dashed" style, so the plot becomes like this:

Now I would like to obtain the Maple plot command that would have generated the above plot, so I can use the command later in my script.  I could not find a menu option to show the Maple command.

Maple 18.02 on windows 7

I'd like to implement this in Maple, but being a newbie having hard time getting the syntax right:

This is what I tried:

a:='a';
f:= i->product( `if`(evalb(i<>j),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);

but it is not skipping the i=j case, since when I call it with f(1) I get division by zero.

f(1);
Error, (in product) numeric exception: division by zero

Tried also

f:= i->product(`if`(evalb(not(i=j)),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);
and few other things. I think the reason it fails is deeper than my level of Maple undertstanding.

How would you do this in Maple?

I am really baffled by this. I was starting to think Maple control system is good, only to find I get an error when I try to obtain the controllability Gammian for a state space system which is time varying.  Maple only seem to support a non-time varying A,B,C,D for this function.  Can someone please confirm this, or may be I am doing something wrong?

I was trying to verify my hand solution for a HW using Maple.

----------------------
restart:
alias(DS=DynamicSystems):
A:=Matrix( [[2,-exp(t)],[exp(-t),1]]);
B:=Matrix([[0],[1]]);
sys:=DS:-StateSpace(A,B);  #created OK
m:=DS:-Grammians(sys);

Error, (in DynamicSystems:-Grammians) symbolic value(s) in model: t, exp(t), exp(-t)
---------------------------------------------------

If the system is time invariant, then it works. Example from help:

-------------------------------------------------
restart:
alias(DS=DynamicSystems):
aSys := DS:-StateSpace( <<-5,3>|<3,-4>>, <<2,3>>, <<1,0>|<0,1>>, <<0,0>> ):
m:=DS:-Grammians(aSys);
---------------------------------

The main advantage of using computer algebra system for control system is to be able to do things using symbolic which is much more powerful than just numerical computation as with Matlab. There is nothing in the above linked to help page that says Maple does not support time varying state space for this function (unless I missed it).

Is it possible to add support for LTV in Maple 19?

ps. note that the ControllabilityMatrix works on LTV:

m:=DS:-ControllabilityMatrix(sys); #OK

But I wanted the Grammian.

Looking at  http://www.maplesoft.com/support/help/maple/view.aspx?path=ImageTools

and

http://www.maplesoft.com/support/help/maple/view.aspx?path=ImageTools%2fFormats

it seems to only support jpeg,tiff,bmp.

This seems like something from 1980's days. Is there another package to load other image formats? Such as png for example, and to export as png?

I'd like to import png file, rescale it in Maple (make thumbnail image) and export it again.

I am using 18.1 on windows 7