Hi, does anyone know how to plot a Bode diagram (phase and amplitude plot)? I am not looking for preparation of data but rather for the technicality of producing a plot that looks like I want, given I have data in the right form (which in my case are three Vectors: frequency, amplitude and phase).

Below is a rough sketch of what I am looking for. Note that the amplitude is on a log scale. It would be acceptable having to take the log of the data "by hand" to allow both vertical scales to be linear (I'd just convert the amplitudes to dB). The important things are the common frequency scale (horizontal) and the separation of amplitude and phase. I know plots has  dualaxisplot, and I know I can use plots:-transform to move a curve around, but I want the two axes on the left side, below each other, rather on the left and right. I'd like the frequency scale in the middle between the two curves, although I could settle on that scale to be below both curves.

I had some look around the Maple applications but did not find anything looking like this.

Thanks,

Mac Dude

I have an expression like this (from an earlier computation):

2*(sum(A*cos(omega*t)^2+cos(omega*t)*B*sin(omega*t)-cos(omega*t)*ymeas(t), t));

I want to distribute the sum over the terms in the expression, i.e.

sum(A*cos(omega*t)^2,t)+sum(cos(omega*t)*B*sin(omega*t,t)+sum(cos(omega*t)*ymeas(t), t)));

I suspect defining a rule and using applyrule should be the way to go, but for the heck of it I can't figure how to do it. The best I can manage is getting the Maple kernel hung with the following construct:

distSum:=sum(A::algebraic+B::algebraic+C::algebraic,D=algebraic)=sum(A,D)+sum(B,D)+sum(C,D);

applyrule(distSum,(5)); # (5) referrs to the expression on line 2 (and it is a proper label in my Maple wrkbook).

I have asked similar questions before and gotten answers; but I am not able to find what I need in MapePrimes (or my faorites, for that matter).

Thanks for any help,

Mac Dude

Hi,

I want to write a proc to calculate exponential averages. Each call will add one data point to the averge. To do that, I need to store the previous average. I can do that by handing the previous average back to the proc at the next call, but I'd rather store it in the proc. Is there a way to guarantee that a variable---once set---remains alive keeping the last value upon entering the proc again? Note that I need the variable to be local to each instance of the proc since I will have several of these running in parallel (I intend to create these procs using the module factory scheme outlined in the programming guide). So I cannot store the previous average in a global variable since that would not be unique to a given instance.

Any ideas out there?

TIA,

Mac Dude

Hi,

Following situation: I have Records with several members. These members in turn have varied expressions assigned to them: some have numbers, one has a Matrix, some have formulae. Example:

q:=Record(l=len,k1=kl/len,R=(a 6x6 Matrix dependent on len and kl/len));

I want to be able to use the limit command on each of the members of q such that each member gets assigned the correct limit of its expression. I.e. I want to write a function limit2 such that

limit2(q,len=0);

yields

Record(l=0,k1=infinity,R=(limit~(the Matrix,len=0))

The trick here is that the members of the Record vary for different Records but I want to write a function limit2 that works for all of these. I can make a list of the members by using exports(q) like this:

exlist:=[exports(q)];

and after some fiddling I found that I can run limit on each member in turn:

for nam in exlist do
  limit~(eval(parse(cat(elm,":-",eval(nam)))),len=0)
end do;

What I have not been able to do is putting the result back into the member of the Record. Usually I would use assign for such a task, but I am unable to get the correct name on the left side that lets me assign to it. These names would of course be q:-l, q:-k1 and q:-R in the above example. I tried the parse(cat(...)) construct above and variations, but in the best case the assignment does not happen, in worse cases I get an error thrown. Never do I get the actual assignment.

Any hint how to do this?

TIA,

M.D.

PS: FWIW, I am doing this on Mape 15.

I am trying to define a new typt and I am beating my head against the wall...

What I have working:

TypeTools:-AddType(Element,'record(l,R)');
 
This defines a type which I can then use in type(xpr,Element) to be false or true depending on whether xpr is a record containing (at least) entries l and R or not.

Now I want to define a type ExpandedLine that is a Vector of Element (Element in the sense above). In fact, in the context of my application I am willing to settle for ExpandedLine being a Vector of record.

Tried various approaches (and making sure Vector is in uneval quotes in the AddType statement) like:

TypeTools:-AddType(ExpandedLine,'Vector'(record));

and variations but no luck.

Any help is appreciated.

Mac Dude