## Recommendations for RPN Calculators? 580

from the still-better-than-an-abacus dept.

*"My trusty old HP 48S graphing calculator, that served me since engineering school, seems to be giving up the ghost. I haven't used it in a few years, but recently I put new batteries in it. It works, but it makes a loud static/white noise sound when it's on. The noise is not as noticeable when I hold it, but when I set it down on a hard surface, it's really loud. Then it sucks the batteries down incredibly fast (I put new batteries in it, and two days later, they were drained). Any suggestions on what I should buy as a replacement?"*

*"I'm in graduate school now, and since I'm taking an accounting course, where they don't want us digging out our laptops during a test, I need to buy another calculator. I'm a big fan of reverse polish notation (RPN), so I'd prefer to get another HP calculator.
Do companies still make calculators? I'd love to get another HP 48, but I'm not even sure if HP even makes calculators like that any longer -- on their web site, they're all cheapo-looking single line deals. I've read about something called an HP 48g, but HP has nothing about it on their web site."*

## HP 48GX (Score:5, Interesting)

Why does HP's current calculator lineup suck [slashdot.org]?

## Re:HP 48GX (Score:5, Informative)

## Keypresses (Score:5, Interesting)

I agree that keypresses saved are minimal, if not sometimes nonexistant in simple equations. In fact, for many simple single-operation equations, the process of learning RPN is far too complicated to justify using it at all.

RPN, however, can be likened to the Dvorak keyboard layout. It is entails a slightly involving process to learn. For many purposes, this is simply a pain. The true power only shines in complicated equations, such as those which make use of brackets.

The following equation shall be typed on an algebraic calculator, followed by an RPN calculator. [;] will be the button name for [Enter].

25 ( 46 ) + 254 - 2462 / ( 645 - 2453 )Algebraic:

25*46+254-2462/(645-2453);RPN:

25;46*254+2462;645;2453-/-In the above example, you will realise that the number of keypresses is exactly the same. (In fact, if you cheat and leave out the second bracket on the algebraic calculator, that calculator edges out the RPN by one keystroke!) However, there are three immediate benefits to the RPN calculator:

Over time, the amount of keypresses will not really be changed too drastically. However, the true power is the convenience and the ease of use. Unfortunately, like the Dvorak keyboard, RPN will slowly fade in the non-specialised markets due to the fact that it takes too much time to learn.

## Re:Keypresses (Score:4, Insightful)

## Re:Keypresses (Score:4, Interesting)

Picking up different notation is easy, but to "convert" your thinking between two different thinking models is much harder and takes longer time.

Mind you, I don't know RPN, but I imagine that at first when learning it, you think of the calculation in a normal way and then covert that to RPN for the calculator, and it'll take time to learn to think of the calculation in RPN.

## Re:Keypresses (Score:5, Insightful)

## Re:Keypresses (Score:4, Interesting)

I agree that keypresses saved are minimal, if not sometimes nonexistant in simple equations. In fact, for many simple single-operation equations, the process of learning RPN is far too complicated to justify using it at all.You can take my HP48GX when you pry it from my cold dead hands. The main advantage of the HP48GX and RPN in general is that I've never had it borrowed in a class by another student for more than 10 seconds. Meanwhile I can watch with a bemused look as they try to figure it out. Then they give it back and grab someone else's lame TI.

## Re:Keypresses (Score:4, Insightful)

## Re:HP 48GX (Score:5, Insightful)

Regardless, HP created the greatest engineering calculators ever made. TI just doesn't cut it--their calculators are for students. What does a student need with a graphing calculator anyway? He should be learning to multiply, divide, and take the square roots of insanely large numbers in his head. That's what school is all about. (That's an overstatement, but still, most of the advanced functions on a graphing calculator are a damaging crutch until you have learned the stuff. Until you are past differential equations, you shouldn't be using anything more than a scientific calculator. And in any advanced math course after that, you barely need any calculator at all. Engineering and Physics are different stories.)

## Re:HP 48GX (Score:5, Interesting)

My primary calculator is the TI-92 PLUS (I used to use a TI-85) and the HP 48 series can't beat the ease of the TI-92 PLUS in terms of entering/performing symbolic operations. What do I use it for? I use it to check that I haven't made a mistake in my pencil and paper grunge work (i.e., arithmetic or algebraic manipulation [my level of math is well beyond calculus so basic algebraic manipulations are considered somewhat grungy]).

The symbolic manipulation of Mathematica is vastly superior to that of the TI-92; however, it is inconceivable that I have ready access to my laptop or another public computer that has Mathematica on it. So, in those moments, I whip out my TI-92 to verify that I didn't make a silly error such as sign dropping or whatever in those calculations which require a page long worth of algebraic manipulation.

## Re:HP 48GX (Score:4, Interesting)

Mathematica is an amazing program, and I have loved using it whenever I have come into contact with it. But I usually find that its symbolic capabilities are only useful for problems that I should be able to do myself. When I need numeric answers, it is usually MATLAB, or more often C++ armed with Boost and Blitz.

## Re:HP 48GX (Score:4, Interesting)

## Re:HP 48GX (Score:3, Informative)

I've got a 20-year old HP-11C that I still use heavily, also an HP 48G that's served well for a few years. These things have been dropped, spilled on, carried in back pockets, etc with not a single problem. These things are built like tanks.

In the same period of time, my wife, who treats her stuff really well, has gone through over a half-dozen TI calculators. They just don't last. And, e

## Calculator Firmware (Score:4, Insightful)

## (ahem) (Score:5, Informative)

And there are many occasions where the graphing functions of my TI have proved useful in the workplace. To name a few:

- being able to view every key I've entered before evaluating the expression

- being able to revise and edit incorrect expressions

- to determine linear regression fits for data sets

- to perform functions like logarithms and square roots on said data sets, in order to linearize them (linearity being checked, of course, by the R^2 correlation of my fit)

- anything at all to do with linear algebra, especially solving systems of equations or matrix manipulations. RREF is a bitch by hand.

For more "pure" math (like Diff. Eq.), I agree that pencil and paper are generally easier. But any applied math (a.k.a. engineering) requires an insane amount of busy work that could

notbe handled with a puny scientific calculator. I know you said Engineering and Physics are different stories, but everything I just wrote could certainly apply to all sciences (even the "soft" ones like Psych. and Sociology), or anything at all requiring data collection.For the record, I use a TI-86 daily at a bio-tech job. It has the stats capabilities of the 83, plus all the good parts of the 85.

## Re:(ahem) (Score:3, Interesting)

I absolutely, positively HAVE to second this statement. I would not have passed Numerical Methods absent the matrix manipulation capabilities of the TI-92 PLUS to check my grind-it-out pencil-and-paper homework!

Sidebar comment: try doing a Newton-Raphson solution of a system of non-linear equations by hand some time. IIRC, that sucker took about eight

## Calm yourself (Score:3, Interesting)

I have been a user of the TI-series of graphing calculators since they first came out with the TI-85/TI-82 line when I was in high school. My Physics teacher even did work for TI over the summers testing out their "new-fangled" (back then) IR sensors, radar sensors, and the 'CBL' which was basically a hand-held data collection microcontroller that could feed data directly into the TI calc's. Since then, (and since doing regular physic

## HP 49G+: new high-end RPN calc (Score:5, Informative)

HP's new calculator division is based in San Diego. I was just at the HHC conference this past weekend, and the division director, marketing director, engineering manager, and lead software engineer were there. They seemed to be

veryconcerned about customer feedback and fixing any problems (or perceived problems) with product quality.Their first new high-end RPN calculator in four years is the HP 49G+, which will be officially announced in the US on October 6. (It's already available in some parts of the world.)

The HP 49G+ has similar capabilities to the HP 49G, but with a larger display (25% more pixels), faster processor (75 MHz ARM), more memory, better keyboard, USB interface, and an SD slot for flash memory expansion.

## (b^x)^y != b^(x+y) (Score:3, Funny)

(b^x)^y = b^(xy)

## Re:HP 48GX (Score:5, Informative)

Absolutely untrue. They're made by the same calculator division that worked on calculators before HP spun off Agilent. It's just that Agilent got the calculator division.

The division was rebranded, not the calculator.

Jeremy

## Agilent (Score:3, Informative)

## Palm PDA + HP4[8,9][S,G]X emulator (Score:3, Informative)

The emulator seems to get good reviews. Unfortunately it doesn't run on my Treo 90.

## its probably in vibrator mode (Score:2, Funny)

## Real Soon Now (Score:5, Informative)

## Re:Real Soon Now (Score:4, Insightful)

## Re:Real Soon Now (Score:3, Informative)

## Re:Real Soon Now (Score:3, Informative)

I love my HP, but I have to say the ONLY

## Re:Real Soon Now (Score:3, Informative)

Back when I was in high school ('87), the HP 12C [hpmuseum.org] reigned supreme. RPN and fast.

The HP 48S and 48G's are much slower than the 12C was for simple arithmetic, which is mostly what those tests were. The slowness for simple arithmetic is probably due to the bit mapped display. Still, they're faster than you can mash the keys ...

But once you start

## Re:Real Soon Now (Score:3, Informative)

I was in high school at the same time and the 12C isn't the calculator you're thinking about. At least I don't think so. The 12C is the financial calculator in that form factor, and wasn't appropriate for those contests since it had only financial functions. No trig, no factorials, no logs, etc. It's an amazingly durable financial calculator however, and one I used in business later in life.

You're probably thinking of the 1

## Re:Real Soon Now (Score:3, Informative)

What they lack in a whiz-bang fast processor, they make up for in efficiency. I've had the same batteries in my HP-48SX since 1994 and it is still going strong. A fast calculator will do you no good if it runs out of juice.

## Buy new batteries (Score:4, Informative)

I have the HP48GX - it's a great calculator, but slow as molasses.Buy new(alkaline) batteries for it. I kid you not, it'll speed it up- if you haven't noticed, performance is noticeably dependent upon battery voltage, and the thing crawls when the batteries get low- possibly on purpose, I dunno.

I've had mine since the early 90's, and I never though of it as slow at anything except menus, graphing, and equation solving. For standard math and even running RPN programs, it's pretty quick- I never felt it was a 'hinderance'.

## speedup (Score:4, Informative)

Once you know that secret, the speed isn't a problem (and I've got a 48S and a 48SX... that's a 1 MHz processor vs. the 2 MHz processor of the G's)

## My choices... (Score:5, Informative)

I also wrote a GTK based one:

ghsilop [sourceforge.net].

## Inverter toast? (Score:5, Informative)

## Re:Inverter toast? (Score:2)

## Re:Inverter toast? (Score:2)

The 49G has been available for over a year now.Over a year... over four [area48.com] is more like it. The 49G+ is cool though - way faster and a larger screen, but it's too bad that it's got a cheap painted plastic casing.

## Zener Diode? (Score:2)

## Re:Inverter toast? (Score:3, Funny)

>>down the IC that is making all the noise (or look for a small IC

>>mounted xformer near on IC) and do some home work. Replace what makes

>>noise and what ic is a PWM if it has one, unless its home brew PWM

>>inversion and learn.

>

>Generally the only time an IC makes a noise is when it sizzles just

>before it goes bang.

>

>But yes, it sounds like a faulty component in the inverter for the TFT

>backp

## depends (Score:2, Interesting)

## Re: TI's have RPN? (Score:3, Insightful)

## Re: TI's have RPN? (Score:2)

## New Hp49G+ (Score:2, Informative)

## Re:New Hp49G+ (Score:3, Informative)

## Try an emulator (Score:2)

## open it up, fix it (Score:2)

## New HP calculators (Score:2)

This new calculator even uses a RISC ARM processor, so it should be fairly speedy. However, I don't know if these calculators have been made available for sale yet.

## RPN really exists? (Score:2, Funny)

## Re:RPN really exists? (Score:2)

There is one drawback - I have a hard time with "regular" calculators. I tend to lose numbers because I expect the RPN behavior of keeping my stack.

## TI-89? (Score:2, Informative)

## Brief HP calculator guide (Score:5, Informative)

16C - awesome calculator for programmers, especially embedded work. There is no better number system converter available at any price. No I can't do bin/dec/hex in my head faster than the 16C and neither can you. Expensive due to relatively low numbers produced.

42S - pricey, even used, but excellent. Two line display, a replacement for the 15C.

32SII - somewhat like a 42S but with single line display, not so nice to use.

15C - same form factor as 16C. At the time HP's top scientific.

11C - a simpler 15C

10C - a simpler 11C

All the above have solid old-HP build quality, excellent key feel and outstanding battery life.

Older HPs are also usable (and may be preferred) - but they have even greater collector status and sometimes fetch higher prices. They will go through batteries faster and the red LEDs can be harder to see.

Forget the 48 models, the 49 and all the new stuff. The 48GX is OK if you have to have graphing but the single and dual-line models have better UI for daily use. The 49? HP died when Carly took over. Now they make pretty colored plastic boxes that only work with windows and they have forgotten how to spell "engineering". In fact they fired all the engineers and HP is now run by MBAs in shiny suits.

(I own 16C, 42s, 15C and 11C models.)

## Re:Brief HP calculator guide (Score:3, Insightful)

I've had one of these for -- can I say this? -- about 20 years. I think I changed the three button cells

oncein that time. The thing is still on my desk, and it still works. And you're right, the thing is great. I find the lack of scientific functions a bit of a drawback, though.## Re:Brief HP calculator guide (Score:2)

## Re:Brief HP calculator guide (Score:4, Interesting)

The only 'problem' with the 49 is the soft non-clicky keys.

Although, it has the added benefit of not being piss slow and has a (thank God) hard case.

## Re:Brief HP calculator guide (Score:2)

## Re:Brief HP calculator guide (Score:2)

16C - awesome calculator for programmers, especially embedded work. There is no better number system converter available at any price. No I can't do bin/dec/hex in my head faster than the 16C and neither can you. Expensive due to relatively low numbers produced.I bought a 16C in 1983 when I got a new job with a 30% pay raise. I figured it was a tool of the trade. I was right, too - and not only is a tool, it's a Snap-On. The thing is damn near indestructible.

The going price for these on eBay is from $125

## Do You Have a PalmPilot? (Score:5, Insightful)

If you have a PalmPilot, you might consider RPN [nthlab.com]. Given your stated requirements, it may not be powerful enough, but it's served me well.

Schwab

## Can be fixed (Score:5, Informative)

## Re:Can be fixed (Score:5, Funny)

This sounds like subharmonic oscillation in the inductor core used in the DC-DC converter. Pop it open, find the inductor, and replace it - thing should be good as new.The sad part is I still have not figured out if you are making a Trek funny or have a soldering iron and know how to use it. God help me, I actually thought to see how the mods would tag it to decide...

## Re:Can be fixed (Score:5, Informative)

This sounds like subharmonic oscillation in the inductor core used in the DC-DC converter.It's funny that someone would think that this comment is funny.

A DC-DC converter converts one voltage (battery voltage) to another (operating voltage). They often work by converting the DC signal to AC oscillations, transforming, and then back to DC.

Subharmonic: a harmonic less than the fundamental frequency. The DC-DC converter switches at a frequency much higher than audible range so you could never hear its switching but you could hear subharmonics.

Inductor: Used to transform the AC current. An introductory electromagnetics text will describe how. Inductors are usually made of coils of wire. Transformers are just two coupled inductors.

Core: Winding the wire around an iron or more exotic core will increase the inductor's efficiency.

If there is damage (i.e. cracked inductor core), you might actually be able to hear the switching used to convert the DC voltages. The cure: replace the inductor.

## The truth about RPN (Score:2, Informative)

I hope when he wrote- "

Do companies still make calculators?", he meant 'still make RPN calculators.'## use a software emulator (Score:2, Informative)

## Get a HP... (Score:2, Funny)

## HP-48 and friends banned on PE Exams (Score:2, Informative)

## What's with RPN? (Score:2)

## Re:What's with RPN? (Score:3, Insightful)

It's the same reason I live in tcsh, but write all my shell scripts using sh.

## A pitch for TI (Score:2)

## Reliability? (Score:2)

## ti89 (Score:2)

## what about a good calculator for linux? (Score:2)

## All you need... (Score:2)

What? It got me through AP calc. The trick is to buy

low.## 48G vs 49G (Score:2, Informative)

In the end, it really depends on what you'll be using it for. I

## Goodbye HP (Score:2)

They no longer make calculators at all [hpcalc.org]. I'm suprised there are still any for sale on the web site. When I mentioned this business change to a calculator geek I know (he was just out of physics grad school), he got this pained look on his face, as if his favorite rock star had been killed or arrested for pedophilia, or both.

This is why I couldn't take any interest in that HP-Compaq soap opera. The dis

## PDA? (Score:5, Interesting)

I use Palm PDAs (my current one is a Tungsten T) and I run a program called RPN [nthlab.com] on it. It's programmable and it has graphing, but I haven't used those features; but as a general-purpose RPN calculator, it's kept me happy.

What I really want is something similar to Palm RPN that is programmable in Python.

Anyway, the best thing about this is that I

alwayshave it with me. I used to have an HP calculator, but it was never handy when I wanted it.steveha

## Re:PDA? Found another! (Score:3, Informative)

I recently got a Palm OS device I can use, a Treo 300 (I'm Graffiti-challenged - way to sloppy a handwriter to ever train myself to make the symbols consistently enough) and have been looking around for a go

## Re:PDA? (Score:2)

## Got a Palm - want a HP - get this (Score:2, Informative)

http://power48.mobilevoodoo.com/

## HP 12c - All the Way (Score:2)

As a geek, I appreciate the fact that they have had a good 20 years (!) to nuke any bugs. The technology is well-thought out and there are no annoying "modes" and menus to deal with.

I recommend using the 12c standard (gold) versus the "platinum".

The manual is written really well, particularly for those who are still warming up to RPN.

## Graphing or not? (Score:5, Insightful)

On the other hand if you need to be able to graph get a HP 48G or 48GX. The GX is expandable but in my experience most people never end up using the expansion packs. Also HP is scheduled to release their new 49G+. Don't let the name fool you though. It is more like a 48 then a 49. None of thoes crappy soft-touch rubber buttons. Also it is based on some ARM processor that will be *much* faster then the 48s and 49.

What ever you do, stay HP. HP builds the best damn calculators on the market.

## Offtopic... (Score:2, Offtopic)

## Some alternatives... (Score:4, Insightful)

a slick RPN emulator...it preserves all the functionality of the TI-83+ while giving you the standard 4-register stack-based RPN functionality.

## Wait until HP releases new calcs. (Score:5, Informative)

## dc! (Score:2)

## HP41CV (Score:2)

## Sheesh, is eBay really that hard to use? (Score:2)

This is worth an Ask Slashdot?

--

## Palm HP48SX, 48GX and 49G Emulator (Score:4, Informative)

It works really well. Hope this helps.

## GNU Emu48CE for Pocket PCs (Score:3, Informative)

## Ha! (Score:3, Funny)

But, anyways, this reminds me of a funny story. I'm sitting in a low-level C++ class, when the teacher decides to show us some Lisp. I found this quite interesting and reminescent of my days with the RPN calculator, so (stupidly) I raised my hands to inquire whether or not the design of Lisp was based on Polish Notation (PN), which would at least cement in my mind how to treat the language.

Teacher: "WHAT! What did you say about Poles?!"

Me: "Polish _Notation_. You know, the mathematical format."

Teacher: "You're making it up!" (at this point, I was fairly stunned)

Me: "It's called that because, theoretically, those Polish mathematicians knew what they were about, you know?"

It was probably the lowest day of my school career. We were getting CS teachers who _didn't know what RPN was_. How embarassing.

As for your calculator, no bloody idea, I just use my TI-83+ whenever the batteries still work.

-Erwos

## I need a manual... (Score:3, Funny)

I'll bake ya some bad-ass cookies if you can give me that

I'm also looking for a hard case. I love my 48, and you can pry it from my cold dead hands. Or from my newly distracted hands when I can get a Palm that'll run the emulator. : )

## Let's see . . (Score:5, Funny)

## Nitpick (Score:3, Informative)

Brits stole our Enigma credit, the French took Maria Sklodowska-Curie so at least let us keep our good ole RPN.

## A capacitor or two! (Score:3, Informative)

You could at least try opening it up to see if there's big (relative to the rest) "can" capacitors (not sure of the proper english term, sorry :-) They often feature in the 100+ uF range.

When they dry out they often (but not always) start looking like they're about to explode (which they sometimes do). And best of all - if the solution is that simple it will probably cost you $2 in parts and a few minutes with a soldering iron.

## Re:rpn = racist (Score:2, Funny)

Why exactly is it "Polish"It's not! it's

RPN, so it's everythingexceptPolish.It's a Norwegien fisherman, a bannana, and a communicable disease, but it's NOT "Polish".

## Re:rpn = racist (Score:5, Informative)

Reverse Polish Notation?!?!? Why exactly is it "Polish"?Because a Polish man came up with the idea?

Prefix and Postfix notation were developed in the 1920's by Jan Lukasiewicz (who was, in fact, Polish). Prefix notation was often called Polish Notation in honor of Lukasiewicz.

Postfix turned out to be useful for computer operations, if you made it into a stack and then did operations upon that stack. It was called Reverse Polish Notation, since postfix is the opposite of prefix, and prefix was called Polish Notation.

Simple.

## Re:TI-83 (Score:2)

Not everything

## Re:Why are you using RPN? (Score:2, Informative)

I find it hard and annoying to use "regular" calculators now. I have been using my HP 48SX for almost ten years now and it still runs like a charm!!!! BTW, HP has revived their calc division. See www.hpcalc.org [hpcalc.org] for details. They have a line of new calculators on the way too!!!

## Yes, it's relevant - at least for software (Score:2)

I think the one I was using just before my PC died was XCalc [tordivel.no], and I have some sort of less satisfactory RPN calculator on my Palm Pilot (it'd be nice to have one that was both good and free, but Palm's programming environment is too annoying to write one myself :-)

## Re:Mathematica (Score:2)

That said, I agree that no calculator can match a decent computer, especially one with a good math package.

## Re:"giving up the ghost" (Score:2)

I guess the idea is that after you die, a ghost comes out of you.

It is odd to think of little HP-48 ghosts coming out of broken calculators. At Halloween, they can haunt people scared of math.

steveha

## Re:"giving up the ghost" (Score:2)

[duck a rotten fruit]

## A bumper sticker I saw once: (Score:2)

(A note for the ignorant - Forth also uses RPN.)