EE Pros: Is RPN still relevant? - Page 1
Forum section: electronics / beginners

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 03, 2017, 08:00:46 pm
content: I've been watching a few tutorials on the Forth programming language and looking into the history of calculators. Reverse Polish Notation seems, to me, to be more intuitive due to it's linear structure.For a new student just getting started, is it worthwhile to learn and utilize RPN in the professional world at this point?

author: helius
author_rank: Super Contributor
timestamp: March 03, 2017, 08:17:33 pm
content: Learning to use a RPN calculator doesn't take long in any case, so not much time wasted if you decide it's not helping you.In terms of the question in your topic,catenativeprogramming languages are as relevant as they've ever been, andpoint-freestyle is used by the most modern languages (like Haskell).

author: Benta
author_rank: Super Contributor
timestamp: March 03, 2017, 08:20:17 pm
content: QuoteProbably not.I say this as an older guy possessing two HP-15C, one always in my jacket, the other on my workbench. Before finding the right App on the phone, or booting the laptop, I have an answer in seconds.But I confess, it's nerdy.Nowadays, starting a big simulator program for calculating an RC network seems to be the way to go.

author: rstofer
author_rank: Super Contributor
timestamp: March 03, 2017, 08:22:54 pm
content: Absolutely! The calculator I prefer to use, an HP48GX, uses ONLY RPN. Some calculators use a mish-mashed RPN and some use either algebraic or text-book entry.My grandson is taking Calc I and when we do the homework, we both use HP48GXs. It is his preferred calculator after using HP Prime, TI Nspire and a couple of others.It takes about 5 minutes to learn RPN, it just isn't a big deal. Try (3+4)(5+6)/(4+5)*(7+8)3 Enter4 Plus5 Enter6 Plus*4 Enter5 Plus7 Enter8 Plus*/Now try it with something else!I'm not an evangelist. I use RPN and have for over 40 years. Use it if you think it helps, skip it if you don't.

author: helius
author_rank: Super Contributor
timestamp: March 03, 2017, 08:27:33 pm
content: Quote from: rstofer on March 03, 2017, 08:22:54 pmUnless you type the ' key

author: rstofer
author_rank: Super Contributor
timestamp: March 03, 2017, 08:37:00 pm
content: Quote from: helius on March 03, 2017, 08:27:33 pmOddly, I have never used that key! Didn't even know what it did...I have been using this calculator for 20 years or so and I still don't know what all the buttons do. I did, however, program a fairly large Celestial Navigation program way back when.

author: LaurentR
author_rank: Frequent Contributor
timestamp: March 03, 2017, 10:40:54 pm
content: Probably not useful. I was an avid RPN user during my school years, then the need for calculations dropped significantly and I learnt to use whatever was handy (e.g. the dreaded Windows Calculator) and it's just fine too. Being an EE doesn't add particular requirements (except needing conversions into binary or hex occasionally, for which RPN is neither better nor worse).RPN feels right for a lot of quick mid-complexity operations, but for larger operations, nothing beats a nice pixeled LCD display and the whole operation displayed so that you can read it back and check it visually.Regardless, you need to know how to handle the operator precedence so that you can either transcribe an existing formula into RPN or write a complex calculation into a normal calculatorQuote from: rstofer on March 03, 2017, 08:22:54 pm

author: claytonedgeuk
author_rank: Contributor
timestamp: March 03, 2017, 11:08:28 pm
content: Quote from: jakeisprobably on March 03, 2017, 08:00:46 pmI learned rpn on one of the hp financial calculators....and when I needed a scientific going to an rpn was an easy choice.For me isn't just about the number of key presses but also about how my mind processes information, ie enter your two numbers and then do something to them (the rpn way)....rather than enter a number...prepare to do something to it...and here is the other number (the non rpn way).I don't think it's a gimmick but as some others have said....its actually quite quick to learn....so easy enough to try and dump it if you don't like it.Sent from my SM-G900F using Tapatalk

author: David Hess
author_rank: Super Contributor
timestamp: March 03, 2017, 11:53:42 pm
content: I have replaced my HP48g with an HP50g and much prefer their RPN operating style. One of the better features becomes apparent when people ask to borrow your calculator:"Hey, can I borrow your calculator?""Sure, here you go."*silence while calculator is inspected*"Um, no thanks."

author: CatalinaWOW
author_rank: Super Contributor
timestamp: March 04, 2017, 12:17:18 am
content: Depends on what you do. The last I knew, there were several programming languages that used RPN internally, and as pointed out above there are a few that present that face to the world.Calculators are mostly a dead end these days, and RPN has gotten quite rare in calculators so that wouldn't justify any real effort.Unless you specialize in writing assemblers or compilers, or focus on one of the few RPN calculators available there really isn't much need to know RPN.That said, it should take you 10-15 minutes to learn 99.9% of what you need in RPN. Not much longer to become proficient in calculator operations. The great thing about RPN is that it is totally consistent. No need to memorize special rules for how to compute x to the y power as is usually the case with algebraic calculators.Why not put it in your toolbox?

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 04, 2017, 12:20:14 am
content: RPN is the only right way, you must learn RPN, all others are worthless .RPN is more like how the microprocessor works, it makes it easy to work on a micro in assembly.

author: w2aew
author_rank: Super Contributor
timestamp: March 04, 2017, 12:46:53 am
content: Use whatever you're comfortable with. I used alegebraic through school (Casio Elsie-mate), but then got hooked on RPN at my first job in 1985. I've used an HP 15C ever since. Also have a 35S on my desk. I even balance my checkbook with a 32S.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 04, 2017, 12:59:23 am
content: I used to get magazines from the library with ads for hp calculators, it was like playboys for nerds.I graduated high school and then 48sx was released and I worked and saved months for it and finally saved up the $300 and bought it from a store called service merchandise. It was under glass like in a jewelry store so I made my purchase then went to the waiting room where the product you bought came out on a belt like luggage in the airport. I almost cried when that little box finally came down the belt for me.

author: djnz
author_rank: Regular Contributor
timestamp: March 04, 2017, 06:38:59 am
content: It's just calculator stuff... not really much to it imo.These days I just have an ipython3 shell running all the time on my laptop...

author: orolo
author_rank: Frequent Contributor
timestamp: March 04, 2017, 10:15:39 am
content: Since you mention Forth, there is other family of languages where RPN is prominent: functional languages, like LISP, scheme, Haskell and the SMLs. These languages are not stack oriented, RPN emerges naturally from function composition. Most functional languages are flexible enough to allow the programmer to redefine most operators as infix, but I have found that the higher the abstraction, the more detrimental it is. For arithmetics it's ok; using monads with infix 'do' notation in Haskell just confuses me, even if there are people that swear it's easier.RPN is the mathematical way of operating. First you get the operands, either in a stack, a tuple, or whatever. Then you apply some function, and get the result.

author: kultakala
author_rank: Regular Contributor
timestamp: March 04, 2017, 11:30:43 am
content: I also started with a HP-41C back in the eighties and never had something else than RPN calculators.It takes less key presses usually than an algebraic one, but i think the biggest advantage is that you have to understand the structure of the equation or whatever you are trying to calculate to be able to do it with an RPN calc.On an algebraic thing you can blindly type in everything and when you did something wrong you dont know where, because you dont think first before using the calculator as you have to do with RPN.

author: newbrain
author_rank: Super Contributor
timestamp: March 04, 2017, 11:35:53 am
content: Do yourself a favor, download "free42" on your phone (fruit or robot), and if you want, to your desktop (fruit, non-flying bird or glazed hole in the wall).It's a one to one emulation ofone of the best(IMHO) HP calculators.Just take some time with RPN,if you are a natural RPN guyit will "click in" very quickly, otherwise you'll hate it.Of course, all the advanced functions take a long time.As for the practical value...as much as I'd love to praise it, I don't think it's that much: apart from computer science, the only other exposure to RPN comes from HP calculators.Quote from: claytonedgeuk on March 03, 2017, 11:08:28 pmSame here:this one(this might show my age...I was just a kid, I swear!).I was able to calculate logs/exp with the financial functions!It's been a kind of imprinting, and I have always had problems with algebraic calculators, as they have all slightly different syntax (even the same brand!).I'm actually evaluating getting a new HP35S...

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: March 04, 2017, 12:22:48 pm
content: Funny you are asking this today, as I started a thread on my own aboutbuying an HP 16c.Having a calculator handy is very much essential to me, though I would not need it every day. For me, it is most convenient to have it sitting on my desk for whatever task comes along instead of using a software based solution - just like notes on real paper work best for me.RPN is fun to use apart from being faster and more natural than working with brackets. There is, however, something very nerdy about it xD

author: TNorthover
author_rank: Contributor
timestamp: March 04, 2017, 07:56:36 pm
content: Quote from: orolo on March 04, 2017, 10:15:39 amThat's a bit of a stretch. There's no notion of a stack in conventional mathematics, and the notation is definitely infix.If I had to say any paradigm was "the mathematical way" I'd go for declarative, like prologue. A mathematical expression representing a series of constraints on the variables involved that may or may not uniquely determine a result.

author: David Hess
author_rank: Super Contributor
timestamp: March 04, 2017, 08:09:47 pm
content: Besides being faster and ultimately easier to use, I like RPN for the stack which holds, and in the case of the HP48g and HP50g, displays multiple results. I prefer a calculator over using a PDA/phone or computer because it is portable, the battery life is effectively unlimited, and the interface is better.While the HP50g has many improvements over the HP48g, it is a step back as far as user interface performance (it is several times slower) and the PDA/phone calculator programs I have tried except for my old Palm Pilot are even worse.

author: orolo
author_rank: Frequent Contributor
timestamp: March 04, 2017, 08:40:23 pm
content: Quote from: TNorthover on March 04, 2017, 07:56:36 pmAny basic algebra textbook will define addition of real numbers as a function from the cartesian product of the real numbers into themselves \$+ : \mathbb{R}\times\mathbb{R} \longrightarrow \mathbb{R}\$, taking a couple numbers into their sum. That is, addition takes a tuple of reals into a real number. Taking a tuple is essentially the same as taking a couple of elements from the top of a stack. When one uses infix notation, one is implicitlycurryingthe addition function, which is in fact stretching its algebraic definition.

author: Unknown
author_rank: Unknown
timestamp: March 04, 2017, 08:44:46 pm
content: Ah, this thread made me nostalgic for theHP 42sI used to use. I went looking to see if you can still get them, but they seem to go for hundreds of dollars now, and it seems that HP's recent (although now decade old) engineering efforts with the 35shave been disappointing.Instead I bought aSwissMicros DM15L cloneof the HP 15C.

author: claytonedgeuk
author_rank: Contributor
timestamp: March 04, 2017, 08:47:32 pm
content: When the Swissmicros shows up...can you report back? I don't think there is even any attempt to conceal the inspiration...but would be keen on hearing how well it matches up.Sent from my SM-G900F using Tapatalk

author: Unknown
author_rank: Unknown
timestamp: March 04, 2017, 08:49:38 pm
content: Quote from: claytonedgeuk on March 04, 2017, 08:47:32 pmSure!

author: Gyro
author_rank: Super Contributor
timestamp: March 04, 2017, 08:59:48 pm
content: Quote from: David Hess on March 04, 2017, 08:09:47 pmAs mentioned in the HP16C thread Istilluse NEOCAL on my old Palm TX. It can be set to display 4 lines of the RPN stack (X,Y,Z,and T) though you can set the stack deeper than that. It does algebraic too, so you don't see RPN in most of the screenshots.I believe the free lite version for Android has the same capability, though misses out on programmer, Financial, etc. functions. I haven't tried it myself, I have a Nokia 3310 (Hey, I'm trendy again)http://www.hudren.com/products/neocal/

author: Benta
author_rank: Super Contributor
timestamp: March 04, 2017, 09:11:35 pm
content: QuoteAre you aware that the SwissMicro devices are less than half the size (in area) of an original HP-15C? I think you may need pointy fingers.HP-15C: ~130 x 95 mm2DM15: 88 x 59 mm2

author: Unknown
author_rank: Unknown
timestamp: March 04, 2017, 09:17:43 pm
content: Quote from: Benta on March 04, 2017, 09:11:35 pmThe DM15 (non-L) version is the small version with the plastic dome keys. However the L ("Large") version is near the original size: 129x79x13mm. It also has normal (apparently pretty good) keys, and is a bit more expensive.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 04, 2017, 09:31:45 pm
content: Quote from: newbrain on March 04, 2017, 11:35:53 amI have a 48sx so I'm using this onehttps://sourceforge.net/projects/x48.berlios/files/

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 04, 2017, 09:53:04 pm
content: So, I think I understand now... Get, and learn how to use an old RPN calculator because it's effective, and secondly, it's a nod to the current generation of EE masters. It might be worth a bit of street cred on a new guy's work station down the road.

author: Benta
author_rank: Super Contributor
timestamp: March 04, 2017, 09:55:10 pm
content: QuoteAh! Thanks. The SwissMicros site is somehow a bit "lobotomized", several of the links don't work.

author: Benta
author_rank: Super Contributor
timestamp: March 04, 2017, 10:01:31 pm
content: QuoteActually, the street/lab cred comes when you whip out the HP-15C from your breast pocket, turn it on and do the calculation in 5 seconds, then return it to your pocket, while the PFY, nose down in his smartphone, is still searching for the calculator app.

author: TNorthover
author_rank: Contributor
timestamp: March 04, 2017, 10:03:13 pm
content: Quote from: orolo on March 04, 2017, 08:40:23 pmThat's a computation-theoretic view of what's going on, and even then it's one particular computational model. By taking the stack as the fundamental object you're baking in RPN or some equivalent. I don't think it's a model used by most mathematicians for their general work.Infix expressions seem to naturally be some kind of tree structure over operations or formulae or whatever (it'll vary by context); and you could indeed use a stack to combine the components into a final one, but it doesn't seem necessary. Alternatively you could make some kind of tree-traversal your basis; some stack involvement is likely as an implementation detail simply because that's how computers work.Edit: And maths itself is just logical formulae with no stack in sight, at its basis. ZF set theory and so on.

author: Benta
author_rank: Super Contributor
timestamp: March 04, 2017, 10:12:48 pm
content: @ orolo and TNorthover:You're scaring people away from HP RPN calculators. Just sayin'

author: bson
author_rank: Unknown
timestamp: March 04, 2017, 10:19:01 pm
content: RPN really excels when chaining calculations, and in fact promotes thinking like this instead of setting up formal expressions to be evaluated left to right. For example, you want to drive a small LED at 2mA, so you have a simple BJT: 12V supply, a resistor, the LED, and a BJT - and you just want a ballpark figure for Ib so you can size a resistor for it to interface to a 3.3V CMOS output.So you start with the supply voltage 12V.Subtract Vce(sat) for the transistor, say 0.25V.Subtract Vf for the LED. Now you're left with the voltage over R.Hmm, maybe we should also check the power dissipation of R?So DUP it on the stack.Divide the voltage on the stack by R, now we have Ic.Calculate the power dissipation: dup, over, *, swap; now we have it in Y and Ic in XApproximate Ie = Ic, and divide by min current gain for the BJTNow we need the base resistor voltage: 3.3V, subtract 0.65 for VbeDivide this by the current in Y: swap, divideNow we have the base resistor resistance in X, and the current limiting resistor dissipation in YAs a result of doing this, you will have implicitly sanity checked every single step of the way.No pen and paper needed to sit and write up expressions to type in on the calculator. In addition to the transcription stage you only get very limited partial results out of algebraic calculators.

author: bson
author_rank: Unknown
timestamp: March 04, 2017, 10:30:33 pm
content: When evaluating formal expressions on an RPN calculator you generally want to work your way from the innermost subexpression and out. This tends to be easier and less error prone than piling up partial values going left to right. Leave that task to compilers. Or get a calculator like theHP-50gHP Prime that has symbolic entry; this lets you enter your expression and check it for correctness before evaluating.

author: orolo
author_rank: Frequent Contributor
timestamp: March 04, 2017, 10:32:47 pm
content: My argument was that RPN arises naturally from function composition. In strict algebraic terms, 2+3 is shorthand for +(2,3) where '+' is a function acting on tuples. It is, therefore, more natural to write 2 3 +, meaning you first define the tuple, and then apply the function. As I mentioned, with arithmetics there is little trouble going infix, bit with higher levels of abstraction things get different. The stack model is mostly irrelevant; it's the tuples that are important. I have often wondered if RPN should be typically used: math notation is burdened by tradition. Perhaps the worst detail is the use of - both for substraction and negative numbers. Lots of trouble for begginers.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 04, 2017, 10:32:56 pm
content: Quote from: jakeisprobably on March 03, 2017, 08:00:46 pmCool. FORTH was a great language of its time. In fact I've been toying with the ideal of re-visiting it myself. There was a really interesting book called "Threaded Interpretive Languages by Loeliger" that is worth a read is you are interested in computer archaeology; this book managed to make my interested enough to spend my last year at school porting FIG FORTH to the Commodore PET! FORTH was big in niche areas like Astronomy for a while.Quote from: jakeisprobably on March 03, 2017, 08:00:46 pmShort answer: NO.Modern calculators have brackets so expressions do not need to be decomposed in the same way they used to. My kids use fx-995ES type calculators and it does most of what they need will no RPN in sight.Long answer: YESRPN is fun! There are commercial RPN calculators like HP35s which I have sitting beside me which are readily available. Personally I grew up without brackets so it works for me.Even longer answer: YES!Build yourself ahttps://sourceforge.net/projects/wp34s/.I have made a few of these in the past and sold them on EBAY. All you need is a HP-30B calculator, often available at bargain prices as there seems to be excess stock (or was when I last looked), a keyboard overlay fromhttp://commerce.hpcalc.org/overlay.phpand then a simple reflash using a USB Serial TTL converter. I love my WP34S but keep forgetting how to use it!

author: artag
author_rank: Super Contributor
timestamp: March 04, 2017, 10:42:25 pm
content: I'm not sure what you mean by 'is RPN still relevant ?'.It's still a pleasure. Isn't that enough ?The thing about calculators is that they're personal. You use them to help your brain. It's reasonable to ask if some programming language is relevant, because there's a good chance you'll use it to earn money and you might want to learn a language that will get you a job. But you learn a calculator's keystrokes for your own use.Despite that, there's probably only one calculator on the planet that IS a stock-in-trade for some profession (though, I hope, not one we'll find represented here). And that's the HP12C.

author: claytonedgeuk
author_rank: Contributor
timestamp: March 04, 2017, 10:50:59 pm
content: Quote from: artag on March 04, 2017, 10:42:25 pmHaha....its actually the hp12c that got me into this. My first rpn....set the standard really.Sent from my SM-G900F using Tapatalk

author: xrunner
author_rank: Super Contributor
timestamp: March 04, 2017, 11:09:12 pm
content: Quote from: newbrain on March 04, 2017, 11:35:53 amThank you! I still have my HP 42S right in front of me, and I didn't know of that app.

author: artag
author_rank: Super Contributor
timestamp: March 05, 2017, 01:04:04 am
content: Quote from: David Hess on March 03, 2017, 11:53:42 pmhttps://xkcd.com/1806/

author: w2aew
author_rank: Super Contributor
timestamp: March 05, 2017, 01:06:46 am
content: ...and one of the best reasons to use RPN calculator at work... ..it will keep most people from borrowing your calculator.

author: xrunner
author_rank: Super Contributor
timestamp: March 05, 2017, 01:07:44 am
content: Quote from: w2aew on March 05, 2017, 01:06:46 am

author: David Hess
author_rank: Super Contributor
timestamp: March 05, 2017, 04:06:53 am
content: Quote from: artag on March 05, 2017, 01:04:04 amHaha, I've done that!I used to rewire my keyboards to swap Caps Lock and Control so that the Control key is adjacent to the A key like God intended. These days I install a driver or edit the registry to do the same thing because modifications to membrane keyboards are difficult but I suspect my next keyboard will have mechanical switches.

author: TNorthover
author_rank: Contributor
timestamp: March 05, 2017, 05:21:40 am
content: Quote from: Benta on March 04, 2017, 10:12:48 pmNot intentionally at all (I just have a weakness for discussing the foundations of maths). My primary calculator is actually an HP-48G. I think a reasonably competent human can use both schemes without diffficulty.Where I think HP really excels is actually the programming language. Before I used Casio graphing calculators, and they use some kind of proprietary bastardised basic dialect. I've played with TI before too without being too impressed. Being able to write programs in terms of something remarkably close to lambda calculus is great!

author: TNorthover
author_rank: Contributor
timestamp: March 05, 2017, 05:44:03 am
content: Quote from: orolo on March 04, 2017, 10:32:47 pmNow that last part I definitely agree with.Personally, I don't think RPN is the right way to go (which isn't to say it's a bad way to enter computations into a computer or calculator at all!). Its strict linearization doesn't really reflect how people actually manipulate concepts, which I think is more of a pattern-matching substitution kind of operation.An interesting data-point is one of the more modern mathematical notations:Feynman diagrams. These are pictures that are used to represent concrete terms in some approximation for quantum mechanics. Syntactically they're not trees, or even acyclic graphs. They're possibly loopy graphs with bells and whistles; but if you give one to a bunch of physicists and ask them to write down an equivalent formula they'll basically agree.So I'm in favour of searching for richer notations rather than trying to linearize everything (except at the human/computer interface where it's essential, and I'm undecided on the best approach).

author: djacobow
author_rank: Super Contributor
timestamp: March 05, 2017, 08:58:53 am
content: I'm still a big RPN fan. I use a 48GX, 32S II, and a couple others.Another neat thing about RPN is how easy it is to implement. I have done so in Perl and in Node.js and use them all the time. Part of the fun of doing it was writing RPN programs to test the calculator, expand taylor series, perform numeric integration, etc. Learning to deal with the stack to hold not just your operands but working variables, counters, etc, can get trippy, especially if your program calls programs that call programs, etc.One simple program that I use every single day is this one:<< inv swap inv + inv >> 'REQ' STOThen I can just do: 2200 3300 REQ and I'll get 1320 -- the equivalent parallel resistance.My calculators (the real ones and the software ones) do complex numbers naturally, too, so I can use the same function with complex impedances and it's all hunky dory.Attached is a picture of the node version running as a chatbot connected to Google talk. This is nice because I can access the calculator from any of my devices, and they all share the same stack because it is hosted on the server.

author: Rick Law
author_rank: Super Contributor
timestamp: March 05, 2017, 08:38:18 pm
content: Quote from: jakeisprobably on March 04, 2017, 09:53:04 pmIt is a bit more than "because it's effective" and "street cred" is computation/programming more than it is EE.Some calculator can resolve an expression and then do the arithmetic. Whereas RPN is a method of doing the arithmetic steps expressed in the expression. Furthermore, RPN is a methodology that is similar to how the CPU used to work. So if youdon't knowhow to evaluate an expression using RPN, youwould not be ableto write assembler code to do the evaluation.An expression contains multiple steps: Answer=A-B*(C+D) is an expression.To add C and D is an arithmetic step to solving the expression expressed above.CPU has changed much. Even simple MCU's can work on numbers in directly in memory (skipping the need to first load them into registers), but it still can't do expressions. It needs a higher level language such as C/C++ to translate the expression into arithmetic steps. In assembly, the programmer is the one doing translation of an expression into arithmetic steps. In many cases, we still need to do some assembler language stuff to make our MCU program do certain things. Your being able to translate an algebraic expression into RPN reassures everyone that you can do arithmetic with your MCU when needed.

author: kultakala
author_rank: Regular Contributor
timestamp: March 05, 2017, 10:00:40 pm
content: I searched all drawers... could only find RPN34S is the one always on my desk

author: Rick Law
author_rank: Super Contributor
timestamp: March 05, 2017, 11:04:29 pm
content: Quote from: kultakala on March 05, 2017, 10:00:40 pmI know I have an HP35 + an HP45 somewhere. I can even picture the name sticker I put on the HP45 eons ago, but I can't find them.Then again, it was hard times during college/grad school. Given my age, it is possible I sold my HP's just to get by dry spells and forgot all about selling it.Always look on the bright side of life. When more severe senility strikes, I would have an infinite collection of great movies I have not seen before. And then shortly after (re)watching them, I would forgot and I can watch it again as "new" movies...

author: amspire
author_rank: Super Contributor
timestamp: March 05, 2017, 11:57:50 pm
content: Back about 1979, we had our own Automated Test bench and I had to make and program fixtures to test 600 ohms telephone-type transformers. The computers were HP 9852A desktop caculators - 64K of ram that had to be shared between the Basic program and running the GPIB card, the RS232 card, the printer, the tape drive and the OS. The end result was that a program was typically a few hundred lines maximum, and variables were A to Z.To handle all the different transformers, I had to write an interpreter that reads the test instructions from a file on the tape for the particular transformer and run it. The only possible way was to write a RPN interpreter because it is just so simple - is the next item in the file a number? If yes, put it on the stack. If it is a letter, it is a command that can pull numbers off the stack. That essentially is the whole interpreter and only takes about 15 minutes to write. In some cases, a command might put numbers back on the stack for the next command to use. No tokenising, no brackets.So a test might be:1 2 I3 4 O100 R1000 F50 V49 51 Mwhich means turn on relays 1 and 2 to connect a winding to the source, turn on relays 3 and 4 to connect the output to the dvm, set the dvm to the 100V AC range, set the source to 1KHz at 50V. Then measure (switch on the source and measure output voltage. If it is between 49V and 51V it passes. Using the RPN order made the programming very simple. The thing is it is also simple for the brain. We often add a huge amount of hidden complexity to things necessarily, particularly now when computing speed and memory is no longer an issue.If I need to use Trig, I often get the numbers first before I even think about which trig function I need. So I calculate the voltage and phase angle first, and once they are on the stack, I will only start to think about "do I need sin() or cos()"?

author: djacobow
author_rank: Super Contributor
timestamp: March 06, 2017, 12:05:59 am
content: Quote from: kultakala on March 05, 2017, 10:00:40 pmIs that 34S the WP34S? The one made from a hacked HP30b?I have one of those and it is awesome. The very idea of it is awesome.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 01:27:44 am
content: Mine has sat loved for a while so I decided a couple months ago to pull out and give it some love. USB to serial and an adapter since I couldn't find the old oneAnd I can transfer files again.

author: helius
author_rank: Super Contributor
timestamp: March 06, 2017, 01:41:53 am
content: There are user-contributed programs that replace the default stack view for the HP48: they are faster and better looking. Also math packages that make it a much more powerful tool.http://www.hpcalc.org

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 02:12:52 am
content: I've been downloading a lot from there lately. I've seen some of the stack replacements. I'm running into memory issues now, but can't find a ram card under $100 on ebay or amazon. I see all the specs for the cards were published, I may have to see if I can design one in kicad.

author: xrunner
author_rank: Super Contributor
timestamp: March 06, 2017, 02:37:35 am
content: I was browsing Ebay and just for the fun of it searched for the HP 42S (which I still have). They are going for over $200! But I'm not selling mine.

author: jakeisprobably
author_rank: Regular Contributor
timestamp: March 06, 2017, 06:15:55 am
content: Quote from: xrunner on March 06, 2017, 02:37:35 am...thus the real reason for starting this thread... I saw how much people were selling RPN calculators for on eBay and figured I was missing something here.... Too many YT cool kids are playing with them. I wanted to know why. This thread is awesome. Thanks

author: kultakala
author_rank: Regular Contributor
timestamp: March 06, 2017, 07:40:44 am
content: Quote from: djacobow on March 06, 2017, 12:05:59 amYes, it is the WP34S!I bought it complete... and it is really good.

author: CJay
author_rank: Super Contributor
timestamp: March 06, 2017, 09:50:53 am
content: Quote from: rstofer on March 03, 2017, 08:22:54 pmAbsolutely that ^^^^^^^^^^Use the tools that get the job done properly in the way that works best for you, I wish people would stress it more often instead of evangelising their favoured choice, after all it's exactly what they're doing.By all means learn RPN but don't feel bad if it doesn't work for you and don't hesitate to try and find a way that's better for you.

author: Vtile
author_rank: Super Contributor
timestamp: March 06, 2017, 10:48:10 am
content: It worked to me, I got through most of my education with end of the nineties TI graphing calc (closer to 80 than 90 as a model number). Then when I reseated myself to school I decided to go with CAS and everything, got RPN machine. I actually feel likenot to had one before as it just fits to my head and makes the boring mindnullifying math a interesting once again.People love it or hate it. There is only one way to find out which group of people you belong.PS. HP35s have trig inaccuracy bug, so if you need high precision trigs you need to get a community written trig package for it (google is your friend).

author: MrAl
author_rank: Super Contributor
timestamp: March 06, 2017, 06:50:10 pm
content: Hi,I see that in most of this thread that RPN is being taken as some sort of physical calculator with buttons and the like, but RPN is not just a kind of calculator, it's a way of evaluating expressions and this means it has wider application than in just an RPN calculator.For example, most Infix calculators probably use RPN internally, because that's the best way to evaluate expressions, for a machine. In human terms, Infix is more widely used but once entered into a device the chances are that sooner or later it will be converted into an RBN string because that is easier for a machine to understand. There's much less logic to doing an expression with RPN than with Infix where you could have 100 parentheses waiting around for that last one to be able to finish the calculation.I've used both low end HP's and high end HP's and low end TI's and high end TI's and i can tell you that for a calculator the least important thing is whether or not it does RPN or not. The most important thing is what kind of apps you can use with it. If you work in a certain field and you cant get an app for something you need to calculate, you want want that calculator. This means that ultimately the best 'calculator' choice is not a calculator at all but a laptop. If you just want to bang around with it then it doesnt matter as much, but for your main work you'll get what you need.Back in the old days when i first discovered the TI high end calc's i loved them, and they did all kinds of stuff. Then i met the advanced HP that did Fourier and Laplace Transforms, then i went back to the TI when it came with even more advanced functions. They are all on the sidelines now, now that i have software for the PC that i wrote myself and also some that i downloaded, and none of those advanced calculators, even all taken together, can even come close to what i have on the computer these days.

author: David Hess
author_rank: Super Contributor
timestamp: March 06, 2017, 07:37:18 pm
content: Quote from: MrAl on March 06, 2017, 06:50:10 pmI use Mathematica but in parallel with my RPN HP50g. A computer and even PDA lacks the convenience of a dedicated calculator when I am designing on paper. The calculator is portable, I don't have to worry about the batteries dying, and it has a superior user interface unless something much more complex is being done and not even then sometimes. Oddly enough it is often faster as well although the 48 MHz ARM based HP50g is slower than the 4 MHz 4-bit HP48g that it replaced.It looks to me like HP is leaving the calculator business so I suspect RPN as used as a calculator interface will finally succumb.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 07:47:13 pm
content: Quote from: jakeisprobably on March 06, 2017, 06:15:55 amMost anything retro si in now. Do a search for Commodore or Amiga or even Atari and you'll see the same high prices.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 07:52:31 pm
content: Quote from: MrAl on March 06, 2017, 06:50:10 pmWhen we all used calculators you couldn't fit a computer in your pocket. One of my early projects was making a data acquisition board for my 48sx. I gave up on that project after a while when you were able to buy DMM's, DSO's etc that could communicate with a PC/laptop.When I learned that forth was postfix I started looking into it, before I wasn't interested as I though it just another language.Now a days I don't use my hp as much as I would like but the feel of the keyboard is still there. Its like asking someone why they have a manual transmission.In reality its probably not relevant much anymore, I still prefer to design my wooddorking or schematics on paper, never got used to cad either.

author: rstofer
author_rank: Super Contributor
timestamp: March 06, 2017, 07:54:53 pm
content: Quote from: MrAl on March 06, 2017, 06:50:10 pmFor the last month, I have been playing with wxMaxima on a PC and it is terrific! No calculator will ever compare to this CAS (Computer Algebra System) with a 27" screen. About this, I am an evangelist! I believe!Not all that many people actually need a CAS in their everyday lives. Those who work in tech probably do but they are probably already using such a thing. Everybody in a college STEM program needs something. I just use the calculators for grunt number crunching.Maple and Octave are also highly regarded as CAS programs. Maple tends to cost money and, although I have downloaded Octave, I haven't started using it. I'm still learning about wxMaxima. Matlab needs to be on the list as well. Mathworks has libraries for everything!

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 07:57:03 pm
content: Quote from: rstofer on March 06, 2017, 07:54:53 pmI grabbed the slackbuilds for this the other day, I just need to find a good tutorial on getting started

author: rstofer
author_rank: Super Contributor
timestamp: March 06, 2017, 08:25:11 pm
content: Quote from: eugenenine on March 06, 2017, 07:57:03 pmIf you are asking about wxMaxima, there are two great books that have terrific examples specifically related to wxMaxima for Calculus. It's simple enough to just take the ideas and put them to use in other areas.https://wxmaximafor.wordpress.com/The User Manual is online but it doesn't seem terribly approachable. It is great as a reference, not so much as a tutorial.I have attached the code for a "Ball Thrown In Air" physics problem. The gravitational constant shows clearly that the experiment wasn't done on Earth. The two graphs are included. If you want, just retype the code and see how it works out. I get most of my education by copying.It is worth noting that the entire problem is contained in lines 2..6. Everything else is just gilding a lily.Line 2 defines the gravitational constantLine 3 defines the initial velocityLine 4 describes the standard equation for motion: H(t)=V0t+1/2at2Line 5 takes the derivative of the function in Line 4 to get v(t), the velocity as a function of time. Note that wxMaxima does the derivative, I didn't have to provide it.Line 6 finds the time when the ball impacts the ground by looking for the second root (away from 0) for the H(t) equation. In other words, where H(t) = 0 with t <> 0.That's it!

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: March 06, 2017, 09:57:53 pm
content: OT: I love how these threads always have a tendency to end up deep in nerd territoryPlease go on!

author: bitseeker
author_rank: Super Contributor
timestamp: March 06, 2017, 10:35:25 pm
content: Quote from: eugenenine on March 04, 2017, 12:59:23 amHoly smokes, that might've been where I bought my 28S back in the day. Been using RPN ever since, even for simple calculations. As someone else posted, Free42 works a treat. Or if you want the HP look, Droid48.I haven't used my 28S in ages. Perhaps I'll hunt down some N-size NiMH rechargeable batteries (it uses three cells).

author: Vtile
author_rank: Super Contributor
timestamp: March 06, 2017, 10:43:12 pm
content: Quote from: eugenenine on March 06, 2017, 07:47:13 pmVintage Casios run for $1 a piece.

author: bitseeker
author_rank: Super Contributor
timestamp: March 06, 2017, 10:46:04 pm
content: Quote from: xrunner on March 06, 2017, 02:37:35 amI'm not selling my HP calculator either. That would be anti-TEA and my other HP gear wouldn't be too happy about it.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 10:52:31 pm
content: Quote from: rstofer on March 06, 2017, 08:25:11 pmYes, wxMaximaBut now I need to re-learn calc and / or physics, the old hdd is getting quite fragmented.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 06, 2017, 10:59:59 pm
content: Quote from: bitseeker on March 06, 2017, 10:35:25 pmI don't know how big of a chain they were. I bought mine in Columbus Ohio, it was on Hamilton Road.

author: bitseeker
author_rank: Super Contributor
timestamp: March 07, 2017, 01:04:57 am
content: Service Merchandise seemed to be everywhere. I remember many fun times watching for my purchase to rumble down the conveyor.NiMH N-type (aka LR-1) batteries seem to be hard to find in the US. So far, I'm only locating sources in the UK.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 07, 2017, 01:11:00 am
content: N size NIMH? Amazon, battery junction, etc all have them.

author: bitseeker
author_rank: Super Contributor
timestamp: March 07, 2017, 04:14:22 am
content: Not that I could find. Everyone has N/LR1 in Alkaline, but not NiMH. Got links?

author: aargee
author_rank: Frequent Contributor
timestamp: March 07, 2017, 11:19:17 am
content: I'd like N size rechargeables as well, the last ones I ever saw were Radio Shack branded Enercell NiCD cells.Still use my HP-11 and HP41 regularly. Really kicked that I passed up on a bargain 'class set' (30 or so calculators as a class set, used in high school) of HP 11 calculators many years back.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 07, 2017, 11:53:47 am
content: Quote from: bitseeker on March 07, 2017, 04:14:22 amI see the first amazon link goes to one that is out of stocksecond link washttps://www.batterybob.com/products/5580-n-size-rechargeable-2-pack-n-360nm/looks to be in stock though I don't know who battery bob isInterstate has retail stores in some places now.http://www.interstatebatteries.com/Products/RT/PID-ASC1055%28Other+Products%29.aspxThe 'also fits' page gives a good laugh if you read about the middle of the list, I didn't know motorola made those types of products

author: MrAl
author_rank: Super Contributor
timestamp: March 07, 2017, 01:57:02 pm
content: Quote from: David Hess on March 06, 2017, 07:37:18 pmHi,Yes the algebraic type software does make life easier.I think i used the HP49 something.Wow HP leaving the calculators? That's nuts. That's how the world changes i guess, and some changes are not good.

author: MrAl
author_rank: Super Contributor
timestamp: March 07, 2017, 02:01:06 pm
content: Quote from: eugenenine on March 06, 2017, 07:52:31 pmHi,Yeah i used calculators when my only computer was a TRS80 ha ha.I dont think i picked up a calculator for a year now. The last calculator i used was actually on the PC computer, a virtual one. I used to use the Windows default calc a lot, but then wrote a program to do all sorts of stuff and then a very simple calculator for just banging some numbers out, which i use mostly now.Most of the other stuff i do now requires an algebraic system anyway so i have to use that now, and i only have that for the PC right now.

author: MrAl
author_rank: Super Contributor
timestamp: March 07, 2017, 02:08:00 pm
content: Quote from: rstofer on March 06, 2017, 07:54:53 pmHi,I second that. I used Maxima too now and then and it allows me to create formulas that would take hours without it or something like that. Before that i used my own software written to perform symbolic algebra, and i still have to use that sometimes because there are problems and limitations to Maxima.I agree that no calculator i have ever seen can come close to what is available for the PC. I have an advanced TI that does differential equations and has CAS, but it still doesnt come close and also TI made a big mistake when they went to "lower case only" variables. That's the dumbest thing i ever saw. My previous TI had upper and lower case which is almost mandatory. Resistors with variable names like "r1", "r2", just dont cut it for me, they should be "R1" and "R2", etc. If a calculator wont let me do that then i wont use it very much. Last time i used that one was just to replace the batteries :-)

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 07, 2017, 02:29:25 pm
content: Quote from: aargee on March 07, 2017, 11:19:17 amI really had to bite my tongue in radio shack as their salesdroid was explaining why their $5 per cell 1200mAH AA NIMH were better than anyone elses. I was buying $2 per cell Sanyo's at the time (pre-eneloop).

author: free_electron
author_rank: Super Contributor
timestamp: March 07, 2017, 04:03:08 pm
content: Quote from: rstofer on March 03, 2017, 08:22:54 pmproblem with rpn is that you have to remember where you are in the 'stack'. and you need to respect the order of operations.me ? gimme brackets. type it in exactly as it is written. no wiggle room.

author: bitseeker
author_rank: Super Contributor
timestamp: March 07, 2017, 11:56:34 pm
content: Quote from: eugenenine on March 07, 2017, 11:53:47 amInteresting. Amazon's search didn't even give me an out of stock one. The first several pages of results were pushing Alkalines at me despite trying "NiMH" and "rechargeable" in the search query.QuoteMe either. But I did find that one via regular web search. It was the only US source I could locate and quite pricey at that.QuoteThanks for the links. I hadn't seen Interstate in my web search. Reasonable price and sold in single units. The 28S uses 3 cells instead of the usual 2 or 4.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 08, 2017, 12:08:51 am
content: Not sure what city your near but we have multiple interstate battery stores around so you can actually drive to them and buy some. Handy when you need UPS batteries, they are heavy to ship.I just did a plain old google search, were you trying to use something useless like bing?

author: firehopper
author_rank: Frequent Contributor
timestamp: March 08, 2017, 01:23:40 am
content: Quote from: eugenenine on March 04, 2017, 12:59:23 amoh god I remember service merchandice.. so many years ago..

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 08, 2017, 01:50:35 am
content: It was 1992.I sat down years ago and scanned boxes of paper, so I still have the original store receipt. I scanned my 48sx manual and uploaded to the museum and they are on the CD set they sell.

author: bitseeker
author_rank: Super Contributor
timestamp: March 08, 2017, 01:58:51 am
content: Quote from: eugenenine on March 08, 2017, 12:08:51 amOh, heavens no! It must've thought I was in the UK or something. Getting results like yours now.Looking forward to using a real RPN calculator again. I wonder if the memory still has my engineering programs from university days.

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 08, 2017, 02:01:12 am
content: Quote from: bitseeker on March 08, 2017, 01:58:51 amYou have to search for those metric size batteries over there

author: cncjerry
author_rank: Unknown
timestamp: March 11, 2017, 04:44:53 am
content: Swissmicros make a full size 15c version as well as the smaller types that are credit card sized. They also have a 42L coming out that is basically the hacked 42 with the intel decimal library. It will be the most accurate calculator on the market. I am on the beta list to test it.I am an RPN type up until the prime came out. That calculator is awesome but you really need to run it in algebraic mode to get the nice print.I own just about all the desireable HP calculators as well as the TI59 types with the card readers. Just love sucking a card into one in the middle of a meeting. I don't have the HP RPN with printer on one of the earlier posts, going to start looking for one again. Bar your doors.I pulled my HP59 out after one of the previous posts as I forgot how easy they are to program. I love the 35 re-do as well in the same picture. I keep a 41cx by my bed in case I wake at night and have to count sheep. I have the 15C limited as well as an original, bummed about the limited's bugs but Swissmicros fixed them in their version. I have a spotless 16C, a 65 and 67. The 65 and 67 just aren't holding up though, they take a lot of love to keep the card readers running.I've been collecting calculators for 40yrs as well as slide rules. Have a bunch of them, and even circular ones that hang on keychains and are full function. I'm sure Eric is reading this post. He gave me quite a few slide rules and calculators as well.

author: bitseeker
author_rank: Super Contributor
timestamp: March 12, 2017, 12:33:23 am
content: Jerry, sounds like a calculator thread in the making (if you haven't already). Sounds like you've got a great collection. Also interested to hear about your Swissmicros experience when you get it.

author: Unknown
author_rank: Unknown
timestamp: March 15, 2017, 07:01:23 am
content: Quote from: claytonedgeuk on March 04, 2017, 08:47:32 pmSo I received my SwissMicros DM15L late last week, and have been using it for a bit. I also bought an HP 12C 30th Anniversary Edition (financial calculator) new off Amazon, which is now made for HP by Kinpo in China.Both have been amazingly handy so far. I forgot what I have been missing out on by using Windows Calculator. It took a fair bit of reading in multi-hundred page thick manuals to get up to speed, but once you remember what all the functions are and what registers they use, it becomes fairly natural to get around.Having both the SwissMicros and the HP/Kinpo is an interesting comparison. I usually suspicious of off-shored manufacturing, but the HP/Kinpo 12C is actually pretty good. The 12C case is almost entirely plastic (excepting the LCD bezel), although I think they always were, but it still feels high quality. The beveled keys have a nice click to them, although it isn't what I would call stiff. It feels light, runs quickly, and has aminimum of bugs, especially compared tosome of the other Kinpo calculators.Conversely the SwissMicros calculator uses all flat keys, no bevel. I like the beveled keys of the HP better as far as the shape and appearance, but there is no deficit in quality in the SwissMicros version and it is quite usable. The key clicks on the SwissMicros are very positive; a bit stiffer than the 12C, but not in a bad way. Just different. The case is also mostly metal (a matte titanium), versus the HP's plastic. Between the keys and the case, the overall feeling is that the SwissMicros is much more rugged. It even feels heavier, although the difference is not that great (132g vs 122g as measured just now). The SwissMicros has a dot matrix LCD screen which I find a little less readable than the HP's segmented LCD, but with regular lighting it isn't a problem. The processor and emulation are very quick.One major benefit that I am seeing for the SwissMicros over the HPs is that they provide a USB connection for easy firmware upgrades, and that the firmware seems to be completely bug free. If you are into programming it, they have also massively expanded the available memory. Apparently there is a new firmware for my 12C to fix the few remaining bugs, but it is not available for download from HP (it seems you need to know somebody) and you need some sort of rare pogo-pin JTAG cable to reprogram it. Not a very great customer experience given that the bugs were fixed almost 8 years ago but the fix never made it into production. Although, it seems like HP wants to forget about their calculator division entirely these days.Overall I think SwissMicros did a pretty good job, and I will also buy their DM16L.

author: claytonedgeuk
author_rank: Contributor
timestamp: March 15, 2017, 07:12:27 am
content: Quote from: Elf on March 15, 2017, 07:01:23 amBrilliant! Thanks Elf....Good to know the swissmicros are as good as they look.I also have the 12c and it's what started me on this silly obsession.Sent from my SM-G900F using Tapatalk

author: MBY
author_rank: Regular Contributor
timestamp: March 27, 2019, 07:56:53 pm
content: Yes, I would say that RPN is very much still relevant today. It's a shame that it is not more mainstream than it is. Once you have learned RPN, you never want to go back to algebraic mode, especially not modern variants that somehow succeed in being stupider than older variants.Its a difference between "easy to use" and "easy to learn". Often, these two gets confused and since algebraic mode are self-explanatory and easy to learn, people tend to stay with algebraich mode. But algebraic mode is NOT easy to use compared to RPN. You will save keystrokes (and thats important on a small interface such as a calculator), time and confusion as you develop a feel for correct entries, subtotals and validation of the results. Things like reciprocals and "out of order entry" of numbers gets much more straight forward with RPN and done correctly you never ever need to use parenthesis¹.Nothing beats having a physical calculator, so don't bother with apps or desktop programs. There is a few ways to get hold of an RPN calculator. Vintage HPs and swiss micros are certainly quality, but the prices can be a setback and if calculator nerdiness is not you thing and you only want a calculator like everyone else to use on an occasional basis you can go for cheap. Searching eBay for RPN calculators and order by price yields many former Soviet calculators, mainly MK-61 and MK-52. They are both very decent calculators but the keyboard kind of sucks. You get used to it and learn how to handle it well, but at the beginning, expect unintentional missed and double-presses on the keyboard. So, if you are unfamiliar with both RPN and a el cheapo keyboard it can maybe be a problem to know whats wrong when unexpected results are given.The newer HP-35s are perhaps the cheapest way to obtain a new western RPN calculator, but it have a few quirks that can drive you mad. Such as the "feature" (read "bug") that a number in floating point mode not always fits the screen and you have to scroll sideways. That's just sloppy design and inexcusable. You almost have to operate the damn thing in fixed point mode with a reduced number of decimals.The HP-32Sii may be the best all-round RPN calculator, but sadly it typically costs at least $100. But if you happen to run by an working HP-32S at a lesser price, don't hesitate, buy it!Learning RPN takes 10-15 minutes of hard work to commit it to your spinal cord². Then, you are free. Forever free.You won't lose your ability to use algebraic mode, but you won't prefer it and you will grunt and swear at the stupidity of it.1) My English defies me here. What is parenthesis in plural? Parenthesises? Parenthesisies? Parenthesisessess? Any combo of 's or s'?2) Or cerebellum I would guess.

author: Gyro
author_rank: Super Contributor
timestamp: March 27, 2019, 08:11:47 pm
content: QuoteWell that was a bit of an old thread resurrection.With regard to the "physical calculator", that rather depends on what you regard as 'physical' these days with smartphones etc. Personally I use Neocal on an old but perfectly serviceable Palm TX, perfectly physical to me.Anyway, the point I want to make is that these devices can normally allow you to view the entire RPN stack, not just the X register. This is invaluable in both ease of learning and reducing errors in operation. There are very few 'physical' RPN calculators (especially the 'classics') that display more than one line.

author: rstofer
author_rank: Super Contributor
timestamp: March 27, 2019, 08:12:19 pm
content: Vo=Vin(1-e-t/RC)This is a nice formula for sorting out calculators. It's not like we don't use it from time to time.

author: bitseeker
author_rank: Super Contributor
timestamp: March 27, 2019, 08:28:52 pm
content: Quote from: MBY on March 27, 2019, 07:56:53 pmYeah, it's a weird one. The ending is modified, rather than appending a suffix, in order to create the plural inflection. Change the 'is' to an 'es'.Singular: parenthesisPlural: parentheses

author: newbrain
author_rank: Super Contributor
timestamp: March 27, 2019, 10:35:20 pm
content: Quote from: bitseeker on March 27, 2019, 08:28:52 pmIt comes from (late) Latin, 3rd declension.The Nominative case ends (often) in -is for the singular and -es for the plural.Many other names in the technical field come from Latin (and Greek, either directly or, once again, through Latin), e.g.: analysis, pl. analyses.IT (In Topic): I just got an HP 35s. Yes, I know it has bugs. Yes, I know it's not really exactly as the old HPs. Still, I feel at home using it.

author: 0culus
author_rank: Super Contributor
timestamp: March 27, 2019, 10:42:58 pm
content: Quote from: Gyro on March 27, 2019, 08:11:47 pmI think it's obvious from context that he means an actual calculator, not an app running on something else.I recently acquired an HP-15C to go with my HP-16C, and I love it. It's not the fastest calculator out there, but it's damn powerful. And user satisfaction? Through the roof.

author: Gyro
author_rank: Super Contributor
timestamp: March 27, 2019, 10:53:08 pm
content: Quote from: 0culus on March 27, 2019, 10:42:58 pmYes, I know it is obvious.The thread is about whether RPN is still relevant though, and the point I was (clearly) making was about physical limitations of their displays and the benefits of having the whole stack visible.Surely we're talking about the advantages of RPN, not (now relatively rare) calculator model 'fandom' (I had a 16C from new but don't miss it compared to what I use now).

author: rstofer
author_rank: Super Contributor
timestamp: March 27, 2019, 11:03:06 pm
content: Quote from: Gyro on March 27, 2019, 10:53:08 pmThe HP 48GX displays 4 levels of stack but I can use the Green Stack button and scroll all the way to the bottom.

author: bson
author_rank: Unknown
timestamp: March 28, 2019, 12:44:20 am
content: My first RPN calculator was an HP-41CV, and one of its truly great features was HP-IL, the Interface Loop, where a bunch of HP-IL devices could be chained into a loop - a tape recorder and one or more HP-IB bridges in particular. This meant the HP-41 was handy for collecting data. So while the hp50g, hp prime, etc can work on large datasets it's really a pain to get measurement data into the calculator to begin with. And if you have data on a computer already why add the complication of transferring it to a calculator. So calculators mainly get used for what is trivial calculations. This is due to them being marketed not for lab use but classrooms where the teacher provides datasets. Something like the HP Prime would be far more useful if it had wifi or ethernet and an LXI-11 implementation with an instrument abstraction and maybe built-in support for some common instruments.

author: MBY
author_rank: Regular Contributor
timestamp: March 28, 2019, 07:23:48 pm
content: Quote from: Gyro on March 27, 2019, 08:11:47 pmOr, full stack view only hamper the effort to learn RPN proper. I don't know the answer, but I would guess that this kind of checking is a bad thing. Like counting parentheses (thank you bitseeker) on a multi-line algebraic calculator. You should probably commit the "RPN routine" to muscle memory and not invoke conscious thought to "confirm" everything. It's like the difference between looking at the keyboard as you write, or develop a more low level feel of what key you stroke and why. I would think that you develop a more deep, unconscious, understanding of RPN (and the same thing goes for algebraic mode as well I would think, but RPN is more suitable for hindbrain operation to off-load the frontal cortex).A physical calculator is obviously acalculator, not a general purpose thingy (smartphone, desktop, tablet, etc), with a proper keyboard whose layout you can commit to muscle memory and such. This applies to algebraic calculators as well, of course. I think this is an important point in the discussion and not only is RPN still relevant, but physical calculators are likewise still relevant.(Btw, "numpad calculators" connected to a computer via USB or PS/2 port are a thing, but for some reason I have never seen a decent one. Scientific, RPN, programmable, etc. No need for leaving the current program/window on a computer, just do the calculation and press a key to insert it exactly where it is needed. *That* would be progress.)

author: rsjsouza
author_rank: Super Contributor
timestamp: March 29, 2019, 01:21:07 am
content: Quote from: newbrain on March 27, 2019, 10:35:20 pmThe HP35S is a great calculator. I got one to leave at the office, where I am not afraid that someone may be tempted to take my HP48GX home. I like that it does 36-bit arithmetic for base conversions, which I use a lot.Quote from: rstofer on March 27, 2019, 11:03:06 pmI love that on the HP48. It is quite easy to get gobs of data and perform multiple operations on them.