@rashmi 

I suggest you to give values to e and l and use dsolve/numeric and odeplot (see ?dsolve,numeric and ?odeplot). Sometimes of use too, you can combine plots for different values of [e, l] using plots:-display.

Edgardo S. Cheb-Terrab 
Physics, Differential Equations and Mathematical Functions, Maplesoft

@juggler 

No, there are no limitations, as far as I can tell .. but I am not the appropriate person to answer this type of question - perhaps people at support@maplesoft.com can give you a more exact answer.

Edgardo S. Cheb-Terrab 
Physics, Differential Equations and Mathematical Functions, Maplesoft

@Mac Dude 

All ok, just one thing: when testing your example with currrent Maple (17), remember to update Physics with the latest version found at the Maplesoft Physics: Research & Development webpage, where you get not only new developments but also bug fixes to the problems reported.

Edgardo S. Cheb-Terrab 
Physics, DEs and Mathematical Functions, Maplesoft

@John Fredsted 

Hi, yes, for sure. I'll post again here, in this thread.

Edgardo S. Cheb-Terrab
Physics, DEs and Mathematical Functions, Maplesoft

@Alejandro Jakubi 

Not sure what you mean. In Physics you can set the metric to whatever you want, including arbitrary. The same in DifferentialGeometry. But it is current Maple, not Maple 12.

Edgardo S. Cheb-Terrab 
Physics, DEs and Mathematical Functions, Maplesoft

@John Fredsted 

There seems to be a bug in assume: after you assume(theta1(t,x,y,z),scalar): and assume(theta2(t,x,y,z),scalar): I would expect getassumptions(theta1(t,x,y,z)) to return {(theta1(t, x, y, z))::scalar} but instead it returns {(theta2(t, x, y, z))::scalar}. From that output, Dagger cannot conclude about theta1(t,x,y,z) and so it returns with dagger instead of conjugate.

The solution to all this is to have one more option in Setup, as said, to indicate that something is scalar, even an algebraic expression perhaps more general than a function. One of the advantages of this approach, as the one already in place to indicate that something is real, is that it does not change the object into something else and therefore you can reuse expressions involving the assumed objects that were entered before the assumption got placed. Likely, you can remove the assumption at any point and reuse expressions entered while the assumptions were holding. All this because when you Setup(real = {a,b,c}) there is no change to a, b or c. 

Have in mind however that I'm somewhat overloaded with activity related to the upcomming Maple release - will probably only be able to implement this new setting in February ...

Edgardo S. Cheb-Terrab
Physics, DEs and Mathematical Functions, Maplesoft

@Carl Love 

In the previous reply I meant this could be done taking the standard `print/diff` (the one there when you restart) as template, but you can also change the one installed by `PDEtools/declare` instead - in fact it is probably easier, despite that the routine is much bigger. So in that case look right after line 92 as shown by showstat: the local variable called tty_ans is the f[x,x,x,y,y] object; insert a couple of lines there to convert to tty_ans := f[3x, 2y]. Note however that if it is a function of only one variable and that variable happens to be the prime variable tty_ans is not an indexed object. To workaround that situation, search for things like ... if dx = prime_variable ... and replace that equation that involves 'prime_variable' by the word false.

Edgardo S. Cheb-Terrab 
Physics, DEs and Mathematical Functions, Maplesoft

@Carl Love 

Take as template the `print/diff` of Maple 17: right after line 20 as shown by showstat(`print/diff`) starts a loop that does most of what you need - a small alteration in the conditional that starts at line 24 would suffice.

Having said that, note that `print/diff` is changed on background by a number of packages in order to display things according to the increased functionality they provide; this is the case when you use PDEtools:-declare and also Physics.  Next, have in mind that the display is one thing, the copy & paste is another one, and if you want the latter to work you need to use something else, e.g. Typesetting:-mcomplete. Finally, print/diff is an internal routine, it changes frequently (e.g. its size for Maple 18 multiplied by two) in order to accomodate new functionality, so just be aware that what you write and works in one release may be conflictive with the print/diff of the next release ... as said these are internal routines, that is the way it is for them.

Edgardo S. Cheb-Terrab 
Physics, DEs and Mathematical Functions, Maplesoft

@peter137

Thank you for your comments. There is a vision behind this project and it's coming along nicely. And yes, updates for the Physics package are being posted around the clock, serveral times a week. Our goal is to accelerate the development with rapid ping-pong-like feedback - with the results available for download right away, and mainly to move the focus into what people are actually doing with the package today. Things like what you see in the two previous posts on Quantum Mechanics (here and here, the third one comes next week) illustrate not only what we can do today with this package but also how constructive this new developmental approach of presenting updates around the clock is.

I wrote a first draft of a book on the use of Physics a long time ago, when this was a University project. It was rather popular among students. I considered updating and completing it many times, but have not had the time. Hopefully, I'll be able to complete it during 2014.

Edgardo S. Cheb-Terrab
Physics, Maplesoft

@Sergio Parreiras 

Hola, :) I'd need the actual Maple input for dsys; you could either paste it in 1D or attach a mw with the 2D input. Advancing: it is not possible to set an independent variable as arbitrary, but there may be ways to achieve the same thing -I need to give a look and with a concrete example to think about is simpler. Also the error interruption is not appropriate, that requires a fix. Y gracias por el feedback Sergio! :)

Best

Edgardo S. Cheb-Terrab
Physics, DEs and Mathematical Functions, Maplesoft

@Sergio Parreiras 

Yes, you can specify both the ordering for the dependent variables, and independent of that also for the independent variables. All this is explained in ?PDEtools,casesplit, give a look please at the section "Optional Arguments". Indeed these are the two options that can make a relevant difference, also the number of rounds; the 'ctl' together with the 'casesplot' options may also server to identify what is the branch that is not terminating, making the whole process hang, and in that way you may be able to get results for the terminating branches (ctl carefully timelimit the non-terminating ones) and then consider any more special strategy for the non-terminating ones.

Edgardo S. Cheb-Terrab 
Physics, DEs and Mathematical Functions, Maplesoft

@ Kevin

Great that it works well for you. Kevin, trying to do (say step by step) the computations that an existing command can do (as in 'all in one step') is an interesting exercise, and frequently tells about functionality missing, or things not working as expected, here and there. Please post these. We will give them a look. Most of the enhancements of the last year are related to people's feedback. Other times you will find that things do work as expected, and posting the example (now as a post instead of as a question) is also interesting - it helps everybody understand different ways of verifying or performing computations.

Edgardo S. Cheb-Terrab
Physics, Maplesoft

@Carl Love 

So, if you have examples where simplify is not idempotent, please post them. I am not saying there are none, but am saying that I am not aware of any in this moment (and I am in charge of simplify).

Edgardo S. Cheb-Terrab
Physics, Maplesoft

@Preben Alsholm 

There is no reason, it is just a historial fact. At the beginning, all dsolve(...) calls were requesting you to give the indeterminate function(s). Mathematica is still that way. I rewrote dsolve in 1997 and introduced the approach I used formerly when writing pdsolve, that is: get the indeterminate(s) from context. Then (only) dsolve/numeric also fell in my hands and so the same. I'll see if we can have the others also getting the indeterminates from context, it makes all the sense.

Edgardo S. Cheb-Terrab
Physics, Maplesoft

@SandorSzabo 

I didn't think about that when doing the previous change, but yes, it makes sense, and is possible to do it. I'll change the code a bit more.

Edgardo S. Cheb-Terrab
Physics, Maplesoft