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Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Posted by Nick on 8 June 2000, 19:18 GMT

Lars Frederiksen has released a very interesting new program called RPN Interface v1.00. HP calculators have had "Reverse Polish Notation" as a feature for a long time now: now, the 89 and the 92 Plus enjoy it as well. For those of you who don't know, RPN is a "stack-based" interface. The design of it makes it much easier and faster to input almost any function, especially those which are increasingly complex. Anyone who enjoys using RPN or who would like to learn a new interface is encouraged to pick this up and give it a whirl. Versions exist for both hardware versions, so it should be compatible on everything except, of course, AMS v2.04.

Update (Nick): About sixty-three quintillion people told me that RPN v1.00 works under AMS v2.04. Thanks to all of them. :)

Update (Magnus): The program has been removed from the ticalc.org server as per the authors request. For access to the program, contact the program author.

Update (Nick): I erred when I posted Lars Frederiksen's RPN program to our archive against his wishes. Furthermore, I was wrong to have posted about flame mail to the comment board under this news item. I apologize for any wrath I may have incurred upon your email boxes and yourselves in the past few days. What I said was out of line and I'd like to apologize for anything bad I have caused them both.

 


The comments below are written by ticalc.org visitors. Their views are not necessarily those of ticalc.org, and ticalc.org takes no responsibility for their content.


Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Sean Kinney  Account Info

I find this interesting. I followed the link to HPCalc.org, and started browsing the information on HP calculators. I have one question. Why hasn't TI implemented any of this stuff? RPN is something that programmers can easily add to the TI line, but how could we add a memory card device?

This is starting to sound a little off topic, as this is not a post about the debate between TI and HP, but it seems TI calcs are better suited for gaming and HP calcs for math and science.

This program looks good. I can't wait to try it out.

     8 June 2000, 22:53 GMT

Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Amalfi Marini  Account Info

a few questions:
It would be cool to emulate a HP calc in our TI89... is it possible?
What happened to Time to team home page?
Downloading rpn from scs homepage:
is it the updated version? it doesn't seem to be...

     8 June 2000, 23:30 GMT

Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

Yes, it is the updated version; there is no version number change.

     9 June 2000, 00:03 GMT


Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
EvanMath

>It would be cool to emulate a HP calc in our TI89... is it possible?

Well, if you mean actually emulate, then no. The HP lines use Saturn chips, which (somebody correct me if I'm wrong) has several 64 bit registers designed for floating point operations. In addition, there are the standard differences between them (different instructions, I/O, etc.). And since the HPs run at (again, I'm not positive) 4 Mhz, there is no way the 10-12Mhz chips in the TI-89 can emulate them.
But if you mean just take HPs OS and put it on the TIs, sure you can do that. In fact, I think that may be somewhat the purpose of PowerTools (http://www.ltech.fr.st/). That is due to be released in July/August according to the author. Plus, for all you French people, he's French.

>What happened to Time to team home page?

The whole ti-news site is "down" (giving a message: (werd 5 days to go), and the message seems to imply it is undergoing some sort of transfer or something that will be completed in 5 days (?)

>Downloading rpn from scs homepage:
>is it the updated version? it doesn't seem to be...

Well, it's not giving me the address error when I rotate an empty stack...

     9 June 2000, 01:08 GMT


Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Amalfi Marini  Account Info

In other words, the TI89 can emulate a HP, but it would take a lot of ram and it would be very slow(un-usable). Maybe someone can rewrote the hole HP rom to make it compatible with the TI89/92, and then run it as a program in our homescreen.(wow!what a dream!!)That means to use all your archive memory, etc...

     9 June 2000, 04:56 GMT

Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Sebastian Reichelt  Account Info
(Web Page)

This seems like a very logical step, especially since the TI-89 internally works with RPN. I wonder why it wasn't implemented in the first place. Too bad I'm so stuck with algebraic notation.

     9 June 2000, 00:23 GMT


Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Daniel Bishop  Account Info

This might be a dumb question, but what's so great about RPN? Why would anyone prefer A B * C D * + to AB+CD?

     9 June 2000, 00:44 GMT

Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
EvanMath

That's not that important, but try typing something much more complex, such as (pardon the formatting)
1 + sqrt(sin(7x-3)-4x)
------------------------------
3(2-17ln(x^2)^2)
in algebraic (normal) mode. How many parhentisis did you leave out? Did you remember to put them around the numerator and denominator? If so, I would just like to say WOW. And if you did get this one, there is an even more complex one in the .pdf file with the program.

     9 June 2000, 01:01 GMT

Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

For large expressions, it can be easier to use RPN to see what happens as you go along instead of using millions of parentheses, just to hit <ENTER> and get the error message "Missing (" or "Missing )". In RPN, you don't need to use parentheses to enter expressions like that.

     9 June 2000, 01:07 GMT


Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Sebastian Reichelt  Account Info
(Web Page)

Or worse: What if you get "Syntax Error"?

     9 June 2000, 02:00 GMT

Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Jeff Meister  Account Info

Horrors! :)

- Jeff

     9 June 2000, 02:29 GMT

Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

Or just "Error". ;-P

     9 June 2000, 03:03 GMT


Re: Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
jaymz Account Info

Or "Address Error".

ok, I know that's far-fetched, but imagine if you get the screen of death :)

     9 June 2000, 15:55 GMT


Re: Re: Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

Yeah, I once got the BSOD (Blue Screen of Death) when I opened Notepad... :-)

     9 June 2000, 16:57 GMT


Re: Re: Re: Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Matt Hockenheimer  Account Info

I tend to get Red Screen of Death more often than blue (I found a program that lets me change the color) :)

     10 June 2000, 03:32 GMT


Re: Re: Re: Re: Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
buraian  Account Info

cool! Where did you get it at?

     11 June 2000, 06:12 GMT


BSOD color
The_Professor  Account Info
(Web Page)

Try x-setup
Search for x-setup at tweakfiles.com
I never get a BSOD, but sometimes I get a GSOD

     12 June 2000, 17:50 GMT


Re: Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
calcfreak901  Account Info
(Web Page)

or "error: memory"

Nerd # 110

     9 June 2000, 14:46 GMT


Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Yonder

Here's a simple example: solve (1+2)*(3+4)

With RPN, you can solve this problem as 1 [ENTER] 2 + 3 [ENTER] 4 + *. That's nine keystrokes. Don't count the four keystrokes needed to enter the numbers, since these will be the same on all calculators. That leaves five keystrokes.

RPN always shows intermediate steps. In this case, it shows three results: 1+2=3, 3+4=7, and 3*7=21. Many people feel that it's important to see every step in a calculation, as this helps to prevent errors.

Non-RPN calculators can certainly solve this problem, and show all intermediate steps. But not in only five keystrokes.

     9 June 2000, 21:39 GMT

Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
deuist Account Info

Reverse Polish blows!!! The reason I got a TI was so I could get away from RP. For those of you who are a little bit older and remember using RP, you should back me up on this: 3+4+5 [ENTER] is a lot easier than 3 [ENTER] 4 [ENTER] 5 [ENTER] +

     9 June 2000, 17:56 GMT

Down with RPN!
Daniel Bishop  Account Info

I agree. Algebraic notation is much easier to understand than RPN.

The only reason for having RPN is that it is simpler to implement than algebraic notation.

but I am a hypocrite because I just wrote an RPN program for the 83.

     9 June 2000, 19:52 GMT


Hurray for RPN!
Jason Schoenfelder  Account Info

It's impossible to lose track of parentheses with RPN. In algebraic mode, if you put in one too many or one too few parentheses, it can take some time to find out where the problem is. With RPN, You can put the operations in any order you want easily without any unwieldy parentheses.

If only I had an 89 or 92/+...

     9 June 2000, 22:47 GMT

Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
Yonder

Most people who criticize RPN don't know how to use it. The post above is a good example.

The procedure described above won't work in RPN; it would sum 4 and 5, and leave 3 above on the stack. The correct way to solve 3+4+5 would be 3 [ENTER] 4 + 5 +. These are exactly the same keys that you would use on a TI-89, only in a different sequence.

So what is the advantage of RPN? Well, RPN always shows every intermediate step. In this case, it would show that 3+4=7, and then that 7+5=12. The TI-89 would only show the final answer, 12.

The TI-89 could show the intermediate step in the calculation, if was input as 3 + 4 [ENTER] + 5 [ENTER]. But this approach takes more keystrokes than RPN, especially when parentheses are required.

In this simple example, the advantage of RPN is not great. But RPN becomes increasingly valuable with more complex calculations. Most professional scientists and engineers like to work through complex problems one step at a time, and RPN is designed to work in exactly that way.

     9 June 2000, 20:27 GMT


Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

Hey - if the reason you got a TI was to avoid it, you don't have to download it. It's that simple. No one's forcing you to get this thing.

     9 June 2000, 21:57 GMT


Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
calcfreak901  Account Info
(Web Page)

as for your last sentence, quite the opposite
the author has severely restricted access

     11 June 2000, 10:03 GMT


Re: Re: Re: Re: Reverse Polish Notation (RPN) Interface v1.0 by Lars Frederiksen
JaggedFlame

Uh... not really. Just because it's not on ticalc.org doesn't mean he's *severely* restricted access. There's still a news item on it, so I'm sure people can still go to scs.ticalc.org and get it. It's not like he took it off the Internet or something.

Anyway, maybe he has his own reasons for doing it, but let's not get into this again...

     11 June 2000, 22:22 GMT

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