Introduction and RPN calculator advice

[NicolaB]

Hello, i've been reading this forum for many years. I'd like to introduce me: my grandpa who worked as a "emergency solver" in the naval field introduced me to RPN with a 32S and at university I got myself a 35S and a 50g; i sold the 35S quickly because there wasn't enough memory to keep all my programs there. On the other hand, my 50g did FEM, statistics, CFD, quad precision stuff and everything imaginable, it's literally a handheld pc. Despite my limited RPL knowledge I wrote a tiny conversion utility that ended up on hpcalc.org, "in2mm".
I did rocket research and in our lab there was this beaten-up bulletproof casio(was it even scientific?) which let's be honest ended up doing 90% of the keypresses, but in the remaining 10% the 50g has proved invaluable. Matlab is crashing? 50g. No FEM or CFD at hand? 50g. Improvised eq? 50g.

Fast forward a few years, and at work I find myself losing time doing calculations on the phone or the pc. I've tried RPN emulators both on the phone and the pc, but nothing is like the physical keyboard on a true RPN machine. I've tried the Casio fx-82 solar II which is very compact and packed with functions but it misses keystrokes and it's not RPN. My 50g has already been abused and it's bulky to carry around, I'd like something compact and RPN.

Therefore I think I'll have to choose between a 15C, 32SII, DM15L, DM32..what would you suggest?

[Hans S.]

(08-11-2023 11:45 AM)NicolaB Wrote:  what would you suggest?

another HP 50 g. It isn't that bulky, isn't it?

Hans

[John Keith]

I have to agree, nothing matches the power and usability of the 50g. There is an HP-48 emulator under development for the DM32. It will not have all of the capabilities of the 50g but it is more compact and has physical keys.

If you can live without RPL, the DM42 is also worthy of consideration. It runs Free42 which is very fast and has 34-digit precision.

[rprosperi]

First, welcome to the Forum, glad you decided to come in and play.

It's hard to give you advice unless you tell us what you will use this machine for going forward; you mentioned a diverse set of things done in the past, but maybe they do and maybe do not still apply... The best machine for balancing a checkbook is hardly good for Bessel Functions, and the reverse is probably just as true.

The 50g is exceeded only by the Prime in raw power, but it doesn't do (real) RPN and to call it quirky and annoying doesn't even come close to capturing it's persona.

HP's new 15c CE (Collector's Edition) should be strongly considered if you like the Voyager form factror, but of the others you mentioned the DM32 is probably the best choice; easy to pick up jsut crank numbers, easy to program, USB port allows easy backup and program exchange.

Lastly, as John mentioned the DM42 is probably the most powerful choice if small and light is important.

[Steve Simpkin]

For a detailed table showing the differences between the HP-15C, DM15L, DM42 and DM32 (among other RPN models), see the following HP Plus RPN Calculator Comparison Table website.

There is a seperate table on the same site that shows the differences between the HP-48SX/S, HP-48GX/G/G+, HP 50G and other RPL/RPN graphing models.

[LinusSch]

(08-11-2023 11:45 AM)NicolaB Wrote:  my 50g did FEM, statistics, CFD, quad precision stuff and everything imaginable, it's literally a handheld pc.

(08-11-2023 11:45 AM)NicolaB Wrote:  I did rocket research and in our lab there was this beaten-up bulletproof casio(was it even scientific?) which let's be honest ended up doing 90% of the keypresses, but in the remaining 10% the 50g has proved invaluable. Matlab is crashing? 50g. No FEM or CFD at hand? 50g. Improvised eq? 50g.

For those remaining 10%, I think the 50g is extremely difficult to replace. If this is what you need, try to find one or two more, maybe look into whether newRPL or DB48x will be able to replace it for you in the future. That may take some porting effort, newRPL is not 100% compatible with HP RPL (they decided to fix +/add on lists, I don't know yet if there's more differences than that but from the discussion on DB48x I probably should be working on documenting that).

(08-11-2023 11:45 AM)NicolaB Wrote:  My 50g has already been abused and it's bulky to carry around, I'd like something compact and RPN.

Therefore I think I'll have to choose between a 15C, 32SII, DM15L, DM32..what would you suggest?

But from this it looks like you're wanting a more portable machine for the first 90% and maybe a bit more of scientific functions and programs so that maybe maybe you get to 95%. For that use case, I myself will choose the DM32 to complement my 50g's so that they may lead a more cuddled life and stay with me for very many years.

These are my reasons for the DM32:
- Being used to RPL I've found it very very helpful to me to see the entire stack at all times, I easily lose numbers from the top if I don't see it because I'm not used to thinking about that.
- The more advanced RPN calculators, 41/42/43, get frustrating for me to use because they probably can do everything I need to do but I don't know how and I wish for my trusty 50g.
- The multiple states, the larger display, the USB interface and the readable mnemonics makes the DM32 by far the most friendly calculator for RPN programming - unless you include the ones that I excluded in my previous point.

How the DM32 avoids frustrating me like the more advanced ones isn't due to just one thing, but the most important part is that it just has way fewer functions. It is small enough that I will actually take the time to work through the 32sii manual and learn the thing - it also helps that I do have a paper copy of that manual in good nick in my native Swedish. And if I forget stuff, the inbuilt help seems to be shaping up to be a quite complete and helpful resource!

For most tasks, for the 90%, using the 32sii/DM32 is just a matter of reading the faceplate (which I much prefer to reading through menus, doubly so since the menus make me think of the 50g and long for that familiarity). As Bob Prosperi likes to point out, this calculator is one of if not the best in HP history to just pick up and use immediately. It appears to be very much the intention here that you should rarely if ever need the manual. To me this is ideal as a secondary calculator, a calculator that you did not go through your education with and therefore do not know inside out.

YMMV, but this is my conclusion in what from I can tell is a quite similar situation.

[Steve Simpkin]

(08-11-2023 11:45 AM)NicolaB Wrote:  ...
Therefore I think I'll have to choose between a 15C, 32SII, DM15L, DM32..what would you suggest?

You may want to visit the HP Calculator Literature site and take a look at the manuals for each of these models to get a better idea of their features.

I will add that while the DM32 is probably easier to initially use because of its limited number of menus, the DM42 has some advantages that you may want to consider. Aside from being more powerful with a larger feature set, the DM42 has multi-character program and variable names, more powerful alphanumeric capabilities, HP-41C program compatibility, simple graphics and sound. It also has a few features that are somewhat similar to those on the HP 50g you are familiar with including, variables and programs accessible by name in soft menus, custom menus and the option to switch to an unlimited stack.
(Photo of DM42)

There are also some additional links for each of the models you are considering on the following HP Plus RPN Calculator Photo Gallery page.

[jgharris]

I agree with Steve. I had a 33s in college and a 50G. In the semester before my last year the EE department decided to not allow any graphing calculators in class for quizzes or exams. Also for any engineers to get licensed the FE/PE require the usage of a scientific calculator so I put the 50g in my bag (for moral support) and used the 33s which worked well for my needs and had a functional rec->polar and polar->rec conversions and some small programming ability. After college working in the field as an engineer (my 33s died back in 2009?) I got the 35s which I used to take and pass the FE/PE.

Now my daily driver is the DM42. To me it's amazing. I can write programs on computer or on the calc and I can backup the entire calculator memory to my spare I keep in my backpack. I write a lot of time-saving programs for work (sometimes simpler than using Mathcad) and also a folder of financial solvers (the good old engineering economics equations such as Uniform Series Sinking Fund, etc.).

I love that Swiss Micros keeps coming out with useful calculators. I own a DM15L, (2) DM42s and I would if they would continue to make additional functional RPN calculators.

[Marco Polo]

Why not consider Plus42 on smartphone?
It takes the best from RPN (HP42), RPL (HP48) and Algebraic (HP27s solver).
The app is very well maintained and very usable both on PC and on smartphone (Android, in my case)

Considering my experience, the physical calculator is having less an less keystrokes as the smartphone is always with me.
I have a 35s on my desk, a 50g in my bag and Plus42 and Emu48 (50g) on smartphone and pc

[jgharris]

Oh yes I do have the free42 app on both my work & personal iPhone. I like the touch of the physical calculator and will reach for it if I'm at my desk. I used to carry it in my shirt pocket (at meetings/field) as the DM42 is less than 1/2" longer than my DM15L.

[NicolaB]

I've sent an answer but i don't see it published.

The 50g is above what i consider too bulky to quickly slide in the pocket, car, and so on. I have more than one RPN calc on both the phone and the notebook, but i keep them just to substitute the integrated algebraic calc when i don't have a physical calculator at hand. I've tried to go "software" but i have to agree with most HP users that a proper physical keyboard makes you work better and faster.
The very useful comparison table left me a bit puzzled because i was taking for granted that with all that cpu power and storage the DM32 and DM42 would only differ in the keyboard layout and the standard menus, being both capable of doing even coffee. Strangely enough it looks like the DM42 has matrixes, while the DM32 has fractions, equation list and unit conversions. Can you explain me why?

[Steve Simpkin]

(08-22-2023 06:46 PM)NicolaB Wrote:  I've sent an answer but i don't see it published.

The 50g is above what i consider too bulky to quickly slide in the pocket, car, and so on. I have more than one RPN calc on both the phone and the notebook, but i keep them just to substitute the integrated algebraic calc when i don't have a physical calculator at hand. I've tried to go "software" but i have to agree with most HP users that a proper physical keyboard makes you work better and faster.
The very useful comparison table left me a bit puzzled because i was taking for granted that with all that cpu power and storage the DM32 and DM42 would only differ in the keyboard layout and the standard menus, being both capable of doing even coffee. Strangely enough it looks like the DM42 has matrixes, while the DM32 has fractions, equation list and unit conversions. Can you explain me why?

My understanding is the the HP-42S originally started out as a replacement/evolution of the HP-41 series. At some point expandability and I/O were dropped and the product design pivoted to be a replacement for the HP-15C. This would explain why the HP-42S (and DM42) programming paradigm is, for the most part, backwards compatible with programs written for the HP-41 series but also includes most of the complex number, matrix, solver and numeric integration functions from the HP-15C.

The HP-32SII, on which the DM32 is based on function-wise, evolved more from the mid-range scientific HP calculator line (such as the HP-11C) with enhancements. While it does not have matrix support, it does have some support for complex numbers, numeric integration and a solver. The algebraic equation list and solver may have evolved from the HP-27S.

The following HP calculator evolution tree, while not perfect, may help illustrate this lineage.
Diagram of Hewlett-Packard Calculator Evolution

[Nigel (UK)]

(08-22-2023 06:46 PM)NicolaB Wrote:  ...
The very useful comparison table left me a bit puzzled because i was taking for granted that with all that cpu power and storage the DM32 and DM42 would only differ in the keyboard layout and the standard menus, being both capable of doing even coffee. Strangely enough it looks like the DM42 has matrixes, while the DM32 has fractions, equation list and unit conversions. Can you explain me why?

Despite having lots of CPU power, to a first approximation these two calculators are intended to reproduce the functionality of the HP originals. The DM42 has gone beyond the HP42S because of the extra features that have been added to Free42 in recent years, and of course both benefit from larger screens and the ability to save and load programs from the built-in flash drive.

Note that the DM42 does not in fact have very much RAM - less than 100k available to the calculator after the operating system has taken its share - and perhaps because of this Plus42 has not been implemented on it, either by SwissMicros or by a third party. The DM32 has a more modern processor with significantly more RAM available; if SwissMicros does make Plus42 available on the new hardware it would surely sell like hot cakes! Pure speculation, but something to hope for.

One nice thing about the DM42 is the range of "alternative" calculators that have been written for the hardware - amongst others, the WP34S, the C47, and (perhaps of most interest to you) the DB48X, which attempts to replicate an RPL calculator of the 48 series. The C47 and DB48X are both works in progress and require a keyboard overlay.

Nigel (UK)

[NicolaB]

I understand the evolution tree, when the chips available were really minimal. And i understand the different physical keyboard layouts to adapt to users who are accustomed to a particular model. That's fine. What i really don't understand is why you can't put a sub- or sub-sub- menu somewhere to provide what couldn't fit in the chip in 1980. For example, an upgradeable equation/constants/units library; matrix operations, and so on in every calculator.

[LinusSch]

(08-24-2023 12:18 PM)NicolaB Wrote:  What i really don't understand is why you can't put a sub- or sub-sub- menu somewhere to provide what couldn't fit in the chip in 1980. For example, an upgradeable equation/constants/units library; matrix operations, and so on in every calculator.

You can, but can you do it well? Such additions easily lead to inconsistent, confusing and/or cumbersome UI. Getting it right turns out to be a lot of work.

The level of completeness found in a 50g comes from a large and long development effort. It is easier these days, there is more knowledge to draw from and more code to use. But there is no longer a large team in a large corporation doing these developments, there is just small teams and enthusiasts doing it in their spare time.

These relatively limited development teams may prioritize quality, polish, ease of use and ease of support over completeness. The last point is extremely important to SwissMicros especially: products that result in a lot of support work can kill small companies and this happens too often.

The great thing about programmable hardware is that enthusiasts can create software to fit their own needs and priorities. Some may decide to throw in everything with less regard for ease and consistency, and crucially no regard for support, instead of the more cautious approach a small company needs to take. Look into C47 and DB48x. Wait for the next gathering of the enthusiasts and see what gets presented there. Maybe find an open project and dive in yourself, if you want what doesn't quite exist.

What you really want may simply be Plus42 on DMCP, in that case it seems you're not the only one, but whether that will ever happen no one knows yet.

I want to run the 50g ROM on new, pocketable, hardware with good calculator keys. Will I ever invest the time to make it possible? Maybe, but it is a bit unlikely. Will someone else do it? Maybe. Will you do it? Maybe you will.

Have fun and please share what solutions you end up with :)

[johnb]

(08-11-2023 11:45 AM)NicolaB Wrote:  Therefore I think I'll have to choose between a 15C, 32SII, DM15L, DM32..what would you suggest?

All the above comments are REALLY good and you should consider everyone's input carefully.

The only thing I have to add is to question: how sensitive you are to the actual size of the machine in your pocket?

For sheer smallness (in the x,y plane), nothing beats the Voyager series. Unless you are also sensitive to its thickness, in which case the 32sII is a little thinner (but a centimeter and a half "taller").

I don't have one to compare, but according to the SwissMicros website, the DM32 and DM42 look to have similar dimensions to a 32sII. Does anyone know if the face is slanted like a 32sII, or if it is straight (i.e. entirely parallel to the back)? For a really picky person, it could make it feel bigger in the pocket.

[spiff72]

(10-11-2023 09:10 PM)johnb Wrote:  

(08-11-2023 11:45 AM)NicolaB Wrote:  Therefore I think I'll have to choose between a 15C, 32SII, DM15L, DM32..what would you suggest?

All the above comments are REALLY good and you should consider everyone's input carefully.

The only thing I have to add is to question: how sensitive you are to the actual size of the machine in your pocket?

For sheer smallness (in the x,y plane), nothing beats the Voyager series. Unless you are also sensitive to its thickness, in which case the 32sII is a little thinner (but a centimeter and a half "taller").

I don't have one to compare, but according to the SwissMicros website, the DM32 and DM42 look to have similar dimensions to a 32sII. Does anyone know if the face is slanted like a 32sII, or if it is straight (i.e. entirely parallel to the back)? For a really picky person, it could make it feel bigger in the pocket.

Here's a photo of the DM42 from the side (it is tapered):
https://imgur.com/gallery/HsC0jpB

[johnb]

(10-12-2023 02:32 AM)spiff72 Wrote:  Here's a photo of the DM42 from the side (it is tapered):
https://imgur.com/gallery/HsC0jpB

So, virtually the same dimensions for a DM42 or DM32 and the original 32sII. Which is great!

* * *

Then, there's the issue of cost.

You haven't said where you're located, so I'll just give price estimates in USD and you can convert if needed.

A used 32sII in good condition is likely your least expensive option: it will run you roughly $50-150 on eBay. Average $95.50, s=27.25 for a sample set of 12. (New-in-box is ridiculous at $450.)

A brand new HP-15c CE will cost you about $130 plus the cost of shipping, depending on where you buy it. (I recommend https://thecalculatorstore.com, as it is owned by a fellow member and he provides excellent customer service.)

A DM15L will cost you nearly the same, so it's a matter of whether you prefer the SwissMicros metal hull (titanium?) or the authentic (and very clicky!) HP buttons.

Prices for used HP-15c (originals) are all over the map. A quick search of eBay showed me prices between $80 and $300, depending on condition and accessories (and greed). A quick sampling of the 12 cheapest (functioning) ones gives an average of $152 with s=39.95.

A new DM42 will cost you $253 plus shipping.

And a DM32 (new hardware, new from-scratch development) is the most expensive of the lot, at $275.



[I have a 15c/CE, 32sII, 15c, 11c, 35s, and 48g, so if I were buying something and didn't care about price, I'd get a DM42 so I could try flashing it with different personalities and pick my favorite... which I'm guessing might turn out to be the C47.]

[Rafa]

Hi everyone,

my lovely gf heard me a couple of time raving about the build quality, feel, and design aesthetic of hp calculators (i own the humble hp 20s) and got me an hp 35s as a birthday present.
I've read little about it but enough to know that it is somehow discounted from the conversation when people talk about hp calculators, but this is another subject.
It is my first RPN calculator and i got at first intrigued by the beautiful fluidity then recognised the benefits of intermediate answers and the fact that i'm actively participating in the calculation and thinking about it as i'm keying it in a sort of back and forth between me and the calculator which is doing the hard bit. The ability to be on top of the calculation as it being carried out step by step appeals to me as it results in more confidence in the final answer.
the switch from algebraic is a bit jarring however but i really like to learn RPN. Can you guys recommend me learning materials on how to learn and master RPN. books or articles in particular would be more helpful for me as i find youtube videos not thorough enough or short and meant to explain in a specific professional application rather than general use.

thanks in advance.

[Steve Simpkin]

(04-04-2024 02:16 PM)Rafa Wrote:  Hi everyone,

my lovely gf heard me a couple of time raving about the build quality, feel, and design aesthetic of hp calculators (i own the humble hp 20s) and got me an hp 35s as a birthday present.
I've read little about it but enough to know that it is somehow discounted from the conversation when people talk about hp calculators, but this is another subject.
It is my first RPN calculator and i got at first intrigued by the beautiful fluidity then recognised the benefits of intermediate answers and the fact that i'm actively participating in the calculation and thinking about it as i'm keying it in a sort of back and forth between me and the calculator which is doing the hard bit. The ability to be on top of the calculation as it being carried out step by step appeals to me as it results in more confidence in the final answer.
the switch from algebraic is a bit jarring however but i really like to learn RPN. Can you guys recommend me learning materials on how to learn and master RPN. books or articles in particular would be more helpful for me as i find youtube videos not thorough enough or short and meant to explain in a specific professional application rather than general use.

thanks in advance.

Here is a great collection of the individual HP Training Aids for the HP 35s, combined together in a 290-page PDF file.

http://sliderule.mraiow.com/w/images/0/0...g_Aids.pdf