mcgrant@elaine3.stanford.edu (Michael Grant) (11/15/90)
In article <BAGCHI.90Nov14181650@snarf.eecs.umich.edu> bagchi@eecs.umich.edu (Ranjan Bagchi) writes: > I'm looking for something to replace my HP28C. It's logical, I >guess, to go to a 48SX. One problem, tho. One of my main beefs with >the 28 is that I can't have variables in a vector or matrix. It's >variable. Didn't work. > So...is there any plans in the work to put this into the >matrix operations? It really doesn't make much sense, at least to me. Well, it certainly would be awfully nice to have symbolic matrix operations. For example, I would like to be able to calculate (sI-A)^-1 almost daily. However, have you considered how much MORE programming that would require to do such a thing? The fact of the matter is that I am more than impressed with the amount of symbolic math that the HP calculators do, and we tend to get spoiled into expecting more! Perhaps a program designed for a more powerful system--like Mathematica-- could handle such functions. But, the on the HP48sx it would simply be too slow and require too much ROM space to support symbolic matrices, in my opinion. On the other hand, depending on what you are doing, there are often ways around such a limitation. Take my example of (sI-A)^-1, often called the _resolvent_ of A. Well, this matrix is the Laplace transform of exp(At), and this turns out to be quite useful in a lot of ways. So, people have come up with many ways to calculate the resolvent without resorting to the slow, symbolic computation of Adj(sI-A)/det(sI-A). Thanks to one particular formula, in fact, I have developed precisely such a program, which does calculations no more complicated than matrix multiplication, and produces a very accurate result QUICKLY (~3 seconds or so for a 4x4 in FAST mode). In addition, there have been symbolic matrix manipulation programs floating around that use the list data structure of the HP. I imagine that they are slow, but if push comes to shove you could use those. So, the HP48sx is probably your best bet if you want to do ANYTHING with matrices, and this probably includes symbolic matrix manipulation as well. If you NEED something more powerful still, you'll need a full-blown computer. One matrix-user's opinion, Michael C. Grant mcgrant@portia.edu (If anyone wants that resolvent program, e-mail me...I have a corollary program that calculates c(sI-A)^-1b as well, even for multi-input, multi- output systems...)
bagchi@eecs.umich.edu (Ranjan Bagchi) (11/15/90)
I'm looking for something to replace my HP28C. It's logical, I guess, to go to a 48SX. One problem, tho. One of my main beefs with the 28 is that I can't have variables in a vector or matrix. It's never made sense to me, and I assumed that it was an oversight. So I went to the HP dealer here, and played with a 48SX. 'twas impressed, with what had been done with matrix entry (a truely painful process, on the 28), and tried to multiply a matrix by a variable. Didn't work. So...is there any plans in the work to put this into the matrix operations? It really doesn't make much sense, at least to me. I'd really like to stick with HPs for my handheld, because of all the other neat stuff that it does. NOt to mention tetris... -rj bagchi@eecs.umich.edu
bagchi@eecs.umich.edu (Ranjan Bagchi) (11/15/90)
To: In article <1990Nov15.000438.13116@portia.Stanford.EDU> mcgrant@elaine3.stanford.edu (Michael Grant) writes: In article <BAGCHI.90Nov14181650@snarf.eecs.umich.edu> bagchi@eecs.umich.edu (Ranjan Bagchi) writes: > I'm looking for something to replace my HP28C. It's logical, I >guess, to go to a 48SX. One problem, tho. One of my main beefs with >the 28 is that I can't have variables in a vector or matrix. It's >variable. Didn't work. > So...is there any plans in the work to put this into the >matrix operations? It really doesn't make much sense, at least to me. Well, it certainly would be awfully nice to have symbolic matrix operations. For example, I would like to be able to calculate (sI-A)^-1 almost daily. However, have you considered how much MORE programming that would require to do such a thing? The fact of the matter is that I am more than impressed with the amount of symbolic math that the HP calculators do, and we tend to get spoiled into expecting more! Unfortunarly, the emacs calc mode (modeled after the HP line of calculators), does support this. I'm naively assuming that it's a matter of how object-oriented the programming style is. One matrix-user's opinion, Michael C. Grant mcgrant@portia.edu (If anyone wants that resolvent program, e-mail me...I have a corollary program that calculates c(sI-A)^-1b as well, even for multi-input, multi- output systems...)
icsu8268@attila.cs.montana.edu (Greenup) (11/16/90)
In a recent article from mcgrant@elaine3.stanford.edu (micheal grant)
there was a mention of something called FAST mode. Have the appropriate bits
been found? can the hp48sx be speeded up similarly to the hp28s?
WHAT NEEDS TO BE DONE?
Also, a big PLEASE and DO HURRY for those who are keeping TETRAS hostage
Thanks in advance-
John Greenup
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John Greenup | snail mail:
Internet: icsu8268@caesar.oscs.montana.edu | P.O. Box 6598
Bitnet : not yet | Bozeman, MT 59771 ram@tellabs.com (Bob Martin) (11/16/90)
In article <2899@dali> icsu8268@attila.cs.montana.edu (Greenup) writes: > In a recent article from mcgrant@elaine3.stanford.edu (micheal grant) >there was a mention of something called FAST mode. Have the appropriate bits >been found? can the hp48sx be speeded up similarly to the hp28s? > WHAT NEEDS TO BE DONE? From what I have heard, the FAST program on the 28S doubles the clock speed, to its maximum acceptable level. The 48SX, which uses the same processor (Saturn), already has the doubled clock speed, so FAST is not possible. -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Bob Martin | ram@tellabs.com ...!uunet!tellab5!ram Tellabs, Inc. |"Listen to me now, and believe me later" - Hans & Franz Lisle, IL. 60532 |"Flibble-dee Floo" - Grumpy Old Man
frechett@boulder.Colorado.EDU (-=Runaway Daemon=-) (11/16/90)
In article <2899@dali> icsu8268@attila.cs.montana.edu (Greenup) writes: > > In a recent article from mcgrant@elaine3.stanford.edu (micheal grant) >there was a mention of something called FAST mode. Have the appropriate bits >been found? can the hp48sx be speeded up similarly to the hp28s? OK I will field this one.. IT ALREADY IS. ;) When you speed up the 28s up to SPEED's highest setting, you are now running at the speed of the hp48sx. The processor is at it's limit.. The 48 cannot pass this limit any more than the 28 but it runs there all the time.. > WHAT NEEDS TO BE DONE? Nothing.. Enjoy the speed of the 48... > Also, a big PLEASE and DO HURRY for those who are keeping TETRAS hostage I agree.. Lets see this thing.. WE WANT Tetras... WE WANT Tetras.. Lets all join in now.. WE WANT WE WANT.. TET.. RAS!!!. (sung to we will rock you) > Thanks in advance- > John Greenup > John Greenup | snail mail: >Internet: icsu8268@caesar.oscs.montana.edu | P.O. Box 6598 >Bitnet : not yet | Bozeman, MT 59771 So.. when are we going to have that FAQ list? I think that SPEED one needs to be added.. Twas fun when I was talking someone into a 48 last week and I mentioned that it runs at SPEED's speed all the time and he went huh??? I sent it to him and now I think he is not going to get a 48 for a while.. Ah well. Can't win them all over. ian -- -=Runaway Daemon=-
brent@oak.circa.ufl.edu (11/16/90)
Someone has already created a nice collection of programs that allow you to use symbolic matrices. Look for sim.mat.vec (or something like that) in the math directory of Wayne Scott's mailserver. It's a very powerful collection, and even includes programs for Eigenvalues and Eigenfunctions.
JSHEA@CLEMSON.CLEMSON.EDU (John Shea) (11/19/90)
Does anybody know if there is a way to turn the screen off, so
that it is not updated at all??? I used to turn off screen updating
on my C-64 to speed it up, and even now when I want my Amiga to print
faster, I switch to a lower resolution screen, and print with the other
program in the background.
I don't even know how the screen updates are handled (I assume
they're similar to CRT scanning, considering the way they flicker, etc.)
John Shea