two queries

[blackeagle7]

Hi,
   I'm a VERY new user of your CAS software. I have some experience with Mathematica, Maxima and Mathcad, with LaTeX, and also with gnuplot (only a few weeks though) and thus was very pleased to find your CAS software. I'm pleasantly surprised by all the functions available. Though a user manual would help a little for some functions which are not so obvious, congratulations for your work and thanks for making this software available freely. I have a HTC P3470 and I'm using the QVGA version of the software.  I enjoy your software as it's pretty fast on my machine. I have 2 questions:

1. Is it possible to start the software directly in the classic mode? Classic mode gives a pretty display of the formulae and functions.
2. After using the software for a while, I guess that buffers or memory can need to be emptied if I want to start a fresh calculation. Do you offer a functionality to clear all memory buffers?



Thanks for your kind help.

Stay bright
blackeagle

[MrMage]

Hello blackeagle,

Thank you for your positive feedback. Remember to tell your friends (especially those with iPhones and iPods!) of PocketCAS.

1. This is not possible, as far as I remember. But the default (session) mode should give you a pretty (mimetex-ed) output, too.
2. Of course. Use the restart() function.

Cheers

Daniel

[blackeagle7]

Hello Daniel,
                    Many thanks for your prompt response in this end-of-year festivity period. The restart() command gives me the null matrix [] if I have nothing in the display or if I have something like t:=58, then restart() gives me restart(t) but I understand that it's doing its job of emptying the buffers.

I had time to look a little more in the functions that are offered. Two functions that I consider useful and which appear to be missing (PLEASE correct me if I'm wrong) are

1. collect. This exists for example in Mathcad. As an example one can have a function involving cos(x) and x, x^2. If I apply collect with cos(x) as the argument, then the expression is rearranged so that cos(x) becomes the major "variable" in the expression. The first term will then always start with cos(x) or one of its powers e.g. cos^2(x) if we have such higher powers in the expression.

2. partial fraction. This is a very useful tool and it helps to expand a rational algebraic expression into its simpler factors.

Yes indeed, I shall pass on the word to friends whom I know would be interested in your CAS software.

Keep up the good work!


Thanks again

Stay bright
blackeagle

[MrMage]

Hi,

1. I'm not sure if this will do exactly what you want, but you might try something like reorder(x^2+2*x+y^2,[y,x])
2. Use partfrac((x^2-2*x+3)/(x^2-3*x+2))

Cheers

Daniel

[blackeagle7]

Hello again,
                   Thanks for your message. I'll try the partial fraction expansion later. I'll give you an example with Mathcad about its collect function:

Say I have this function: a^4 + a^3 *b *c + a^3 *b

With Mathcad, I have:

---collecting with respect to a^3, I get: (b + b *c)a^3 + a^4

---collecting with respect to a, I get: a^4 + (b + b *c)a^3

---collecting with respect to b, I get: (a^3 *c + a^3)b + a^4

I've tried with the reorder command as you suggested but I don't get any good result. "reorder" is just re-ordering the variables a and b.

If it's not yet available, maybe you would like to consider implementing it in a future release.

Thanks again for your quick reply.

Stay bright
blackeagle

[MrMage]

Hi,

I am not the developer of the CAS, so I am not going to add such functionality. You might ask Bernard Parisse (http://www-fourier.ujf-grenoble.fr/~parisse/english.html) to add this functionality, but I will probably not build a new version of the CAS kernel for Windows Mobile in the near future.

Cheers

Daniel

[blackeagle7]

Hello,
        Thanks. I shall try to get in touch with Mr Bernard Parisse when time permits. The fact that I have "played" with mature CAS software for the desktop computer "makes" me look for similar features in your CAS software. Of course, I understand that I can't expect all functionalities as in Mathcad to be available. Your CAS software is a very welcome software indeed and should be well commended.

I am happy as your CAS software is today. Being available for pocket devices freely means that anyone can work efficiently almost anywhere. For much heavier computations, then one can always resort to a desktop CAS software.


Thanks again.

Stay bright
blackeagle

[MrMage]

Thank you for appreciating what you got already. Comments like this are always very welcome :-)

Thanks for the good Karma, by the way.

[blackeagle7]

Hi,
    You're welcome for the good karma .  I have a small comment. In the Ana/Phy section, we have the "laplace" command. At first, I thought it was the Laplace Transform (which is used to transform a differential equation to an algebraic one) but looking at the arguments it takes, I understood that it's computing the laplacian of a function. That said, you do have it in the right section just among rot, div and potential for field computations. .

In electromagnetics or heat transfer for example, the Laplace's equation is a special case of the Poisson's equation when the right hand side is zero. But when we simply call the function, we name the function as either laplacian or Laplacian.

Maybe renaming "laplace" to laplacian or Laplacian would be more appropriate.

I had time to look at the manual available on the home page of Bernard Parisse. He does have laplace and laplacian as separate functions.

PS: I have tried to find the collect function in his manual. He does have "tcollect" and "combine" but they are not quite what the collect in Mathcad does. I will have to search more carefully in his manual.

Looking forward to hearing from you and thanks for your comments.



Stay bright
Blackeagle

[MrMage]

Maybe renaming "laplace" to laplacian or Laplacian would be more appropriate.

True, but the space there already is very limited, and I'm not going to create a release soon. Feel free to edit keyboard.xml yourself, though.

[/quote]PS: I have tried to find the collect function in his manual. He does have "tcollect" and "combine" but they are not quite what the collect in Mathcad does. I will have to search more carefully in his manual.[/quote]

That's why I didn't suggest them to you ;-)

[blackeagle7]

Hello Daniel,
                    Thanks for the tip on editing the xml file. The important thing is that invoking the "laplace" function displays "laplacian(,[x,y,z])" and anyone proficient in advanced Maths will understand "immediately" and also it's surrounded by functions used to describe fields.

Yeah, this is why "tcollect" is in the trigonometry section . It has its right place there.

Thanks and my best wishes for the end of year festivities.

Stay bright
blackeagle