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HP 28S REF and RREF
04-09-2020, 12:56 AM (This post was last modified: 04-09-2020 12:57 AM by edryer.)
Post: #1
HP 28S REF and RREF
So after a while with my old Sharp EL 9900 (an old tank of a graphing calculator from 2000, my main workhorse picked up for less than $10) decided to start using the HP 28S again.

Very surprised there is no way on the HP to perform Matrix (Reduced) Row Echelon Form... i.e. no REF or RREF functions, was it not envisaged as useful for professionals? RREF would be a one step linear system solver!

Almost all later graphing calculators from most manufacturers had this functionality (as I assume does the HP 48SX and beyond).

To me a curious omission, as the HP 28S otherwise has great matrix/vector functionality (not as good as the 48's/50's with eigen stuff but still pretty good).

HP-28S (1988 US model), DM41X (2020)
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04-09-2020, 07:01 AM (This post was last modified: 04-09-2020 07:02 AM by J-F Garnier.)
Post: #2
RE: HP 28S REF and RREF
(04-09-2020 12:56 AM)edryer Wrote:  Very surprised there is no way on the HP to perform Matrix (Reduced) Row Echelon Form... i.e. no REF or RREF functions, was it not envisaged as useful for professionals? RREF would be a one step linear system solver!

Almost all later graphing calculators from most manufacturers had this functionality (as I assume does the HP 48SX and beyond).

To me a curious omission, as the HP 28S otherwise has great matrix/vector functionality (not as good as the 48's/50's with eigen stuff but still pretty good).

The 28S was released in 1988, and the RREF command (and many other) was introduced only in the 48GX in 1993.
Also the HP-28S has 128kB of ROM, whereas the 48GX has 512 kB.
Not surprising that the 48G series is much more powerful.
Still I like the 28S a lot (except the battery door of course).

J-F
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04-13-2020, 11:19 PM (This post was last modified: 04-13-2020 11:19 PM by edryer.)
Post: #3
RE: HP 28S REF and RREF
thanks for this reply.

still, the 28S is my absolute favourite HP, with a sublime keyboard and feature range, never used the limited graphing capabilities though, for the most part it is great for my Linear Algebra course.
I wasn't aware of the 128 K in the 28S, nor that the 48G/GX had 512 K.

Did the 48S/SX have REF/RREF functions, and also 512 K ROM?
I always assumed the S/SX and G/GX had very similar functionaity...

HP-28S (1988 US model), DM41X (2020)
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04-13-2020, 11:55 PM (This post was last modified: 04-14-2020 02:14 AM by Steve Simpkin.)
Post: #4
RE: HP 28S REF and RREF
(04-13-2020 11:19 PM)edryer Wrote:  ...
Did the 48S/SX have REF/RREF functions, and also 512 K ROM?

I always assumed the S/SX and G/GX had very similar functionality...

As mentioned by J-F Garnier, the RREF command, and many others, were introduced in the 48GX in 1993. This command did not exist in the HP48SX/S models introduced in 1990.

The HP-48SX/S had 256K of ROM.
http://www.brouhaha.com/~eric/hpcalc/memory_size.html

What's new in the HP48 G/GX?
By Joe Horn:
https://www.hpcalc.org/hp48/docs/faq/48f...tml#ss10.1

More information on the development of the HP-48G series is available in the Aug 1994 issue of HP Journal.
https://www.hpl.hp.com/hpjournal/pdfs/Is...994-08.pdf

Edit: Fixed several errors and added HP-48GX/G info from Joe Horn.
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