Calculator Operations RPN versus DAL
Calculator Operations RPN versus DAL
(OP)
There is a discussion ongoing on the structural engineering forum regarding the current range of HP calculators.
I was unable to comment on the discussion as I have tried a HP a few times and didn't like it. I didn't like the Reverse Polish Notation (RPN) system. I currently use a Casio CFX-9850G which uses the DAL (Direct Algebraic Logic or something similar) system. I have had it a number of years and cannot fault it. However, I seem to be alone in my department as most everyone uses a HP with RPN.
Why does RPN seem more popular? Is it a better operating method for calculators? Should I bite the bullet, ditch my Casio and move over to a HP?
I was unable to comment on the discussion as I have tried a HP a few times and didn't like it. I didn't like the Reverse Polish Notation (RPN) system. I currently use a Casio CFX-9850G which uses the DAL (Direct Algebraic Logic or something similar) system. I have had it a number of years and cannot fault it. However, I seem to be alone in my department as most everyone uses a HP with RPN.
Why does RPN seem more popular? Is it a better operating method for calculators? Should I bite the bullet, ditch my Casio and move over to a HP?
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RE: Calculator Operations RPN versus DAL
RPN might be a bit more popular in that, at least in my experience, HP came out with calculators that were really useful for engineering before anyone else and they utilized the RPN notation.
Regards,
RE: Calculator Operations RPN versus DAL
I too would say use what you are most comfortable with. I personally like the RPN because once you force yourself to use it a while, you begin to realize that for calcs with a few more variables in it, the RPN really helps you fly through the numbers without having to remember all the ().
For basic X times Y either method is fine.
RE: Calculator Operations RPN versus DAL
RE: Calculator Operations RPN versus DAL
For me, RPN is easier for getting "intermediate" results:
y = mx + (b+c)
If I want to know what mx and b+c is while I am doing my work.
In my life today, my Excel spreadsheet gets more use than my HP 15C and 32S (both RPN). I still have my HPs, I just use it less often for work, and more for quick calcs.
"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
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RE: Calculator Operations RPN versus DAL
When you get right down to it though, most computer language and hardware architectures are stack oriented, hence, more like RPN, even at the calculator level. The parentheses simply force a new stack entry.
Anyways, use whatever gets you the correct answer the fastest. Any other consideration is really irrelevant.
TTFN
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RE: Calculator Operations RPN versus DAL
RE: Calculator Operations RPN versus DAL
Why is my handle 65Roses?
Please visit http://www.cff.org/aboutCFFoundation/About65Roses/ to learn why!
RE: Calculator Operations RPN versus DAL
RE: Calculator Operations RPN versus DAL
Took ages to figure out why pressing 2 followed by squareroot gave "Error" all the time...
I also managed to put it in some weird mode where 22/7 == 3
RE: Calculator Operations RPN versus DAL
RPN was specially invented to use less memory and to avoid the use of parenthesis.
For example:
((((1+2)*3+4)*5+6)*7+... would be
1 2 + 3 * 4 + 5 * 6 + 7 * ....
That is the key advantage.
RE: Calculator Operations RPN versus DAL
BTW, I use the TI and my HP48G interchangeably... I keep one where I'm working and one at home. I like both and HP's 'stack' architecture was originally chosen because of the manner in which data was entered into a computer... similar with Forth... they needed 'real time' speed.
Dik
RE: Calculator Operations RPN versus DAL
Like others, I was confused by RPN when I got my first HP calculator around 1978 but it made sense when the HP manual explained it in terms of order of execution and how the RPN method is the same method that one would use when evalulating a numerical expression by hand.
In other words, when evaluating by hand you don't simply start at the left and work towards the right (unless you can stack up those intermediate results in your brain, I can't), you start somewhere "in the middle", evaluating expressions within parentheses first, then by other standard procedures.
For example, in my original "Solving Problems With Your HP Calculator" (complete with helpful Charlie Chaplin cartoon manipulating the stack register) from 1978 they give the example of:
5*((3/4)-(5/2)+(4*3))/(3*0.213)
Evaluating with an RPN calculator proceeds just as though you were solving by hand, start with the innermost parentheses, then work outward (there may be more than one path taken). The intermediate results are stored in the stack, then brought down as they are needed. Solving with an algebraic calculator, well, I guess the modern ones you can enter the whole expression and then even edit it, then evaluate it. That's pretty handy too. But by the time those were available I was an HP convert. Nowadays, I still use my trusty old HP-15C but for anything fancy I will make an Excel spreadsheet (and use it over and over again).
Some Polish mathematician found that the minimum requirement for a stack is 4, anything less and values would pop off the top and be lost. But some later HP calculators have very large stacks (100?). I have an HP 48GX stuck somewhere in my desk, I don't have much use for it.
By the way, the old HP-15C "Advanced Functions Handbook" (separate purchase) had an incredible Appendix on "Accuracy of Numerical Calculations". I still refer to that to this day. It was written by some very brilliant person(s) but in a form that even I can understand.
RE: Calculator Operations RPN versus DAL
Personally I like DAL, although I can use RPN at a push. I don't use RPN often enough to develop proficiency in it, so it is determined effort rather than second nature. Practice would change that, but since I can have a result from my Casio FX-115 much quicker at present than I would with a RPN calculator I have little reason to change for the sake of saving a few keystrokes some time in the future.
For the sake of the age profile, I'm 35. By the time I was using a scientific calculator at school the RPN types were an expensive minority and Casio had cornered the bulk of the market.
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Sometimes I only open my mouth to swap feet...
RE: Calculator Operations RPN versus DAL
Dik
RE: Calculator Operations RPN versus DAL
I am now 65. I started with a national semiconductor RPN calculator, then went to a TI59, until somebody pinched it.
I then went to a Sharp PC1600 which was a strange beast, you entered the equation as you wrote it then hit enter. It was also programmable in basic but would only hold 900 lines of code, I now use a Casio CFX-9750G.The small brother to the one Ussuri uses, the large screen allows you to enter the whole equation and see what you have entered before you hit the execute key. I have no problem switching between DAL and RPN.except when I am entering strings of numbers on a DAL and get to the last one.
B.E.
RE: Calculator Operations RPN versus DAL
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Sometimes I only open my mouth to swap feet...
RE: Calculator Operations RPN versus DAL
I think the RPN vs normal logic is a religous argument - RPN is to some extent more closely related to slide rules... but I'm not really sure that translating a normal equation into RPN is a robust solution.
I don't actually care much either way - a Toshiba Libretto running an early version of Mathcad was as portable as a proper calculator, and 200 times as useful. But some bastard stole mine to fund his crack habit.
Cheers
Greg Locock
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RE: Calculator Operations RPN versus DAL
I really do not use the graphing function that much, the large screen and the fact that I can program the calculator appeal to me the most, I have a large number of trig functions programmed into mine.
Greg,
Was that Mathcad 3.1 or 3.0 ?
B.E.
RE: Calculator Operations RPN versus DAL
I preferred 3.1 to be honest
Cheers
Greg Locock
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RE: Calculator Operations RPN versus DAL
RE: Calculator Operations RPN versus DAL
Would you have the CD-ROM for that Libretto? I still have one but the CD-ROM is missing. It was a great little tool.
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Sometimes I only open my mouth to swap feet...
RE: Calculator Operations RPN versus DAL
I only got floppies until v.8
TTFN
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RE: Calculator Operations RPN versus DAL
1. Something my dad (IBM-er) brought home circa 1974. Had red lights.
2. TI-30
3. TI-35
4. TI-44
5. TI-66
6. HP-28C (borrowed a friend's to do matrix algebra). Discovered I liked RPN better than AOS.
7. HP-28S (bought my own)
8. HP-33S (for PE exam, don't like it)
9. HP-48S ahhhhh.
10. HP-48G emulator on my computer ahhhhhhhX2.
RE: Calculator Operations RPN versus DAL
At the time I lost/had it stolen (not sure which) I couldn't afford/find another one and settled for a slightly cheaper fx-7400G.
It's not as good and I'm no where near as good on it.
RE: Calculator Operations RPN versus DAL
I was forced to do massive numerical calculations on a HP48-G in 1989 by a perveted professor when much more suitable computer tools were already available. The project included by necessity complex nested procedures and massive data entry for table lookups.
My ahhhh moment came after that when I threw my HP48G in the drawer and went back to desktop computer-based tools.
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RE: Calculator Operations RPN versus DAL
I didn't have the CD drive for the Libretto, I used the IR link back to my PC, and prayed that I'd never have to reinstall W95. I have still got the floppy drive, but use that with my 'new' laptop.
Cheers
Greg Locock
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RE: Calculator Operations RPN versus DAL
TTFN
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RE: Calculator Operations RPN versus DAL
After that my various employers lost interest!
Cheers
Greg Locock
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RE: Calculator Operations RPN versus DAL
Over the years I discovered another great advantage of RPN - folks would come into my office and ask for a calculator, see mine on the desk, pick it up, look at it and put it down again because they couldn't work out how to use it. RPN = theft proof
RE: Calculator Operations RPN versus DAL
It is mostly the HP 15 I use. Lately, I have the desktop calculator shortcut on my screen. And also use a slide rule.
Love RPN. And did a lot of FORTH programming, too. It was the only way to squeeze OS, program and data into a 64 kB memory space. Still use FORTH for an ARM7 processor. But have come to use SPIN and Propasm for the propeller processor lately (thanks to IR that hinted me).
Gunnar Englund
www.gke.org
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RE: Calculator Operations RPN versus DAL
Dik
RE: Calculator Operations RPN versus DAL
First one I bought was a Commodore 4148, followed by a Commodore 4190.
When the nicads died I bought a cheapo Texas LCD since I didn't need hyperbolic functions anymore... followed by a Casio with hex arithmetic functions.
The latest Sharp el531w is the only one I've ever encountered that lets you set it up so that 22/7 = 3, a facility that I never knew I needed.
RE: Calculator Operations RPN versus DAL
RE: Calculator Operations RPN versus DAL
B.E.
RE: Calculator Operations RPN versus DAL
B.E.
RE: Calculator Operations RPN versus DAL
What do you not like about the HP33s? I've heard from many people who were 48G(X) users throughout the years who also don't like the 33s. I assumed it was just because they were upset the 48G series was no longer allowed for PE exams. I've never used one myself but it is one of the ugliest HPs I've ever seen.
Why is my handle 65Roses?
Please visit http://www.cff.org/aboutCFFoundation/About65Roses/ to learn why!
RE: Calculator Operations RPN versus DAL