## DM41L versus DM15?

Forum for discussion of the DM10, DM11, DM12, DM15, DM16 and DM41 units
keithdalby
Posts: 564
Joined: Mon Apr 24, 2017 8:38 pm

### DM41L versus DM15?

I own a DM-15 and a DM-42. I also own an HP-12c and like the size and form factor and would like a scientific calculator the same shape/size, but I'm finding it difficult to justify another purchase.

The DM-15 can handle hyperbolic trig, factorials, permutations and combinations. Can the DM-41L?

If the DM-41L has all the functions that the DM-15 has, then is the only additional feature the alpha? The DM-42 has all the features I want, but the wrong form factor. The DM-41L is the right form factor, but I'm curious what it really adds to the DM-15L.

My dilemma: if the DM-41L only really adds alpha to the DM-15L (and the clock, which I don't use much... or maybe I would if I had it), then can I really justify over £120ish for another calculator that adds little more functionality than the DM-15 I already have?

Mmmm, the more I think about it, the more I want to purchase the DM-41L anyway... please help me justify it!!!
grsbanks
Posts: 1122
Joined: Tue Apr 25, 2017 11:23 am
Location: Preston, Lancs, UK
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### Re: DM41L versus DM15?

There are a few features that the DM15 has and the DM41 does not. An integrator, solver, matrix calculus and complex numbers. I don't think the DM41 does hyperbolic trig either.

What the DM41 does get you is the ability to name programs in the same way you do the DM42. Alpha input is another thing, and a completely user-assignable keyboard. You get 319 registers worth of memory to store programs in main memory and since the V25 update you get 362 registers of extended memory instead of "only" 124.

Look for a manual for the HP-41CX on line, that's what you're getting in a landscape format, plus one extra HP-82181A X-Mem module built in as of firmware V25.

Please note that the DM41 is significantly slower than the DM15 for similar operations. So, if you do need any of the features present in the DM15 and not in the DM41 then use the DM15. A program to replace the feature will not run anywhere near as fast. On the HPMuseum.org forum, someone suggested a form of benchmark using transcendental functions. I ran the benchmarks with my HP-15C, HP-41C, HP-42S, DM15L, DM41L and DM42 among others and got these results:

Code: Select all

Calc       100 iter   1000 iter   10^4 iter   10^5 iter
-------------------------------------------------------
HP-15C     313s
HP-41C     155s        1418s
DM41L      42.26s      407.14s
HP-42S     31s         291s
DM15L      14s         135s
DM42 (bat) 0.67s       6.66s       65.71s     654s
DM42 (USB) 0.28s       2.67s       26.33s     261.81s
HP Prime   0.036s      0.29s       2.78s      27.3s
There are only 10 kinds of people in the world: those who understand binary and those who do not.
Boub65
Posts: 176
Joined: Tue Sep 12, 2017 4:34 pm
Location: Rabat, Morocco

### Re: DM41L versus DM15?

You can do a "HP41 vs HP15" web search. The subject has been hammered!

For me DM15L is a ONE (1) program calculator vs DM41L a MULTIPLE programs calculator (multiple program spaces, global labeling, etc...). The rest is "details"
Last edited by Boub65 on Sun Jan 21, 2018 12:39 pm, edited 1 time in total.
Sincèrement, Sincerely, 73,
Boubker

2xDM15L, DM41L, DM42 SN#00855 (+one lost during shipping), DM41X #00707
TI-89 titanium, CASIO fx-cg50 (to play with micropython)

There are three kinds of people in the world: those who know math and those who don't.
Walter
Posts: 2074
Joined: Tue May 02, 2017 11:13 am
Location: Close to FRA, Germany

### Re: DM41L versus DM15?

Boub65 wrote:
Sun Jan 21, 2018 12:21 pm
For me DM15L is a ONE (1) program calculator vs DM41L a MULTIPLE programs calculator (multiple program spaces, global labeling, etc...).

EDIT: That's strange - the old quote changed due to the author correcting his old post. Never seen such stuff before. Close to falsifying records ...
Last edited by Walter on Sun Jan 21, 2018 1:23 pm, edited 1 time in total.
DM42 SN: 00041 β
WP 43S running on this device

HP-35, HP-45, ..., HP-35S; WP 34S & WP 31S for obvious reasons; DM16L
Boub65
Posts: 176
Joined: Tue Sep 12, 2017 4:34 pm
Location: Rabat, Morocco

### Re: DM41L versus DM15?

@walter thanks, corrected.
Sincèrement, Sincerely, 73,
Boubker

2xDM15L, DM41L, DM42 SN#00855 (+one lost during shipping), DM41X #00707
TI-89 titanium, CASIO fx-cg50 (to play with micropython)

There are three kinds of people in the world: those who know math and those who don't.
grsbanks
Posts: 1122
Joined: Tue Apr 25, 2017 11:23 am
Location: Preston, Lancs, UK
Contact:

### Re: DM41L versus DM15?

There are plenty of things that you will be able to do with a 41 but not with a 15. For example, right now I'm writing a program that will allow me to keep track of time that I spend on multiple projects. It uses the time module, of course, and it stores start/stop details of individual projects in data files in X-Mem. There are proper, human-readable prompts thanks to the 41's alpha abilities and input is collected by reading the keyboard with GETKEY. None of that is possible with a DM15...

If you're a bit of a nerd as your recent Facebook post would suggest, then you'll have plenty of fun with the DM41L. Just remember to make liberal use of 'ASN', which assigns functions to keys in USER mode.
There are only 10 kinds of people in the world: those who understand binary and those who do not.
keithdalby
Posts: 564
Joined: Mon Apr 24, 2017 8:38 pm

### Re: DM41L versus DM15?

grsbanks wrote:
Sun Jan 21, 2018 12:49 pm
If you're a bit of a nerd as your recent Facebook post would suggest, then you'll have plenty of fun with the DM41L.
Not sure that I really carry the credentials to be called a nerd in the context of this forum, but in other forums (fora?)... well, it's all relative.

We are in the process of house-buying right now, but my accountant (AKA Mrs Dalby) has hinted that if there's money left over, I might be possibly maybe allowed to buy another calculator. Maybe.
keithdalby
Posts: 564
Joined: Mon Apr 24, 2017 8:38 pm

### Re: DM41L versus DM15?

I know I can just look this up, but it's faster for me to just ask this to people who know: can the DM-41L do linear regression? Gradients and intercepts from /Sigma +?
grsbanks
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### Re: DM41L versus DM15?

keithdalby wrote:
Sun Jan 21, 2018 2:13 pm
I know I can just look this up, but it's faster for me to just ask this to people who know: can the DM-41L do linear regression? Gradients and intercepts from /Sigma +?
Interesting. It doesn't look like it does.

It'll give you the mean and (sample) standard deviation of your dataset but it's up to you to work out the slope and intercept for linear regression by the looks of it.
There are only 10 kinds of people in the world: those who understand binary and those who do not.
keithdalby
Posts: 564
Joined: Mon Apr 24, 2017 8:38 pm

### Re: DM41L versus DM15?

Sorry, yep, looking up the manual and found that it doesn't give you LR stuff, but it gives you enough stats to write a quick program to calculate them, which is fine.

In my head, I'm planning the ultimate pocket high school physics lab tool

(Edited to add: which, incidentally, I have with the DM42... except, you know.... P/L)