Which HP calculator had "The New Accuracy" first?

06212020, 01:35 PM
(This post was last modified: 06212020 01:36 PM by Joe Horn.)
Post: #1




Which HP calculator had "The New Accuracy" first?
HP91 or HP22?
Background: Dennis Harm's article "The New Accuracy: Making 2^3=8" (HP Journal, October 1976, pages 1617) explains why the original HP calculators get 8.000000003 for 2^3, and how the HP91 (and later models) get exactly 8. This implies that the HP91 was the first HP calculator to have "the new accuracy". The HP91 was introduced in March 1976. However, the CCE33 emulator of the HP22 also gets exactly 8 for 2^3, and the HP22 was introduced in September 1975 (only one month after the HP25, which returns 8.000000003 for 2^3). Is the CCE33 emulator of the HP22 faulty (I don't see how that's possible, since it uses the original HP microcode), or was the HP22 the first calculator with "the new accuracy"? Request: If you own a real, physical HP22 that is working, please calculate 2^3 on it, then press Shift 9, and tell us what is displayed. Thanks! <0ɸ0> Joe 

06212020, 02:44 PM
(This post was last modified: 06212020 02:45 PM by AndiGer.)
Post: #2




RE: Which HP calculator had "The New Accuracy" first?
Checked in my physical HP22  displays 8.000000000
S/N 1708S BTW: Was a wonderful opportunity to look for that machine in my pile :) 

06212020, 05:48 PM
(This post was last modified: 06212020 06:42 PM by aurelio.)
Post: #3




RE: Which HP calculator had "The New Accuracy" first?
Hi Joe, Hi Andy, I read the Dennis Harm's article and the post.
The 35 (three versions) and all the classic calculators return 8.000000002 for 2^3 and not 8.000000003, as written, where am I wrong? the same result on the woodstocks up to the 25 

06212020, 06:49 PM
(This post was last modified: 06212020 06:50 PM by DaveBr.)
Post: #4




RE: Which HP calculator had "The New Accuracy" first?
My HP22 s/n 1602A1****
2^3 = 8.000000000 Dave RPN rules! 

06212020, 07:07 PM
(This post was last modified: 06212020 07:42 PM by JF Garnier.)
Post: #5




RE: Which HP calculator had "The New Accuracy" first?
The bible "A Guide to HP handheld calculators and Computers" also mentions the HP91 as the first to have the more accurate algorithms.
Could it be possible that the HP22 was updated at some point? Anybody with a HP22 made in 1975? JF [Edit: The HP22 was the first to get the improvement according to this source :) ] 

06212020, 08:01 PM
Post: #6




RE: Which HP calculator had "The New Accuracy" first?
(06212020 07:07 PM)JF Garnier Wrote: Anybody with a HP22 made in 1975? Close! My HP22 is S/N 1601A... and displays 8.000000000 I think Joe was just testing us.... Bob Prosperi 

06212020, 08:37 PM
Post: #7




RE: Which HP calculator had "The New Accuracy" first?  
06222020, 01:07 AM
Post: #8




RE: Which HP calculator had "The New Accuracy" first?
(06212020 05:48 PM)aurelio Wrote: Hi Joe, Hi Andy, I read the Dennis Harm's article and the post. Oops! You're quite right. Let's call it a typo (even though it was more accurately a braino). (06212020 07:07 PM)JF Garnier Wrote: [Edit: The HP22 was the first to get the improvement according to this source :) ] OH NO! We covered all this just 3 years ago, but I don't remember having done so AT ALL. The conclusion is undeniable: I'm now officially OLD... two months before my 65th birthday. But I *DO* remember that I enjoy playing with HP calculators, so at least I still have that. (06212020 08:37 PM)aurelio Wrote:(06212020 08:01 PM)rprosperi Wrote: I think Joe was just testing us....I think so, Bob No, all the replies above say that their HP22 returns exactly 8, which disagrees with the commonly told story that the first HP with the new accuracy was the HP91. That common misconception should be corrected. But now please excuse me, I need a nap. <0ɸ0> Joe 

06222020, 01:25 AM
Post: #9




RE: Which HP calculator had "The New Accuracy" first?
It's possible that the code really was originally developed for the HP91 (the first TopCat), and then it was also used for the HP22 (both use Woodstock technology), which was likely much quicker to market.
The 91 was the first machine in a totally new line with many innovations such as case, layout and keyboard design, thermal printer, adding ENG notation, etc. while the HP22 was just another Woodstock which had been out for many months already, so not unreasonable that they wrote it for the 91, copied it in the 22 and the 22 simply were produced 6 months earlier. Just speculation, but it does explain the observed facts and stories. Bob Prosperi 

06222020, 07:41 AM
Post: #10




RE: Which HP calculator had "The New Accuracy" first?
In the article of the HP Journal introducing the HP21/22/25 (reproduced here) we can read this:
"To improve the final results given by the HP22, improvements were made to the standard HP21 family arithmetic subroutines. The y^x algorithm was extended to handle negative numbers to integer powersfor example (2)^2 or (2)^2and a subroutine was developed to calculate the expression (1 +y)^x, which occurs frequently in financial equations. " JF 

06222020, 07:52 AM
Post: #11




RE: Which HP calculator had "The New Accuracy" first?
Hi all,
my HP22 (S/N 1512S...) return 8,0000000. Cheers. Ignazio ______________________________________ RPN...What else! 

06222020, 09:51 AM
Post: #12




RE: Which HP calculator had "The New Accuracy" first?
I'm just a little worried by a test case that involves small integers like this. Another example given by Kahan as an accuracy test is this:
729^33.5 / 3^201 1 It would be interesting to me to see this calculation done on an HP22, or HP91, or both, or any other in Joe's timeline of accuracy. Here are my results: HP15C LE: zero HP25: 9.99E08 (same as HP35 with V4 ROM) 

06222020, 11:34 AM
Post: #13




RE: Which HP calculator had "The New Accuracy" first?
(06222020 09:51 AM)EdS2 Wrote: I'm just a little worried by a test case that involves small integers like this. Another example given by Kahan as an accuracy test is this: Using the emulator, only 32e, 37e, 38e/c give 0 as result. cheers Tony 

06222020, 12:04 PM
(This post was last modified: 06222020 12:05 PM by aurelio.)
Post: #14




RE: Which HP calculator had "The New Accuracy" first?
(06222020 01:07 AM)Joe Horn Wrote: OH NO! We covered all this just 3 years ago, but I don't remember having done so AT ALL. The conclusion is undeniable: I'm now officially OLD... two months before my 65th birthday.Don't worry Joe, +1 even if I'm just a bit younger... it happens, this forum is the "wikipedia" of the calculators and you, like most of the other pioneer members, are the "relators" of the encyclopedia, thankyou for that (06222020 01:07 AM)Joe Horn Wrote:I was just jocking Joe. of course, don't take it for true(06212020 08:37 PM)aurelio Wrote: I think so, BobNo, all the replies above say that their HP22 returns exactly 8, which disagrees with the commonly told story that the first HP with the new accuracy was the HP91. That common misconception should be corrected. But now please excuse me, I need a nap. 

06222020, 01:53 PM
Post: #15




RE: Which HP calculator had "The New Accuracy" first?
(06222020 12:04 PM)aurelio Wrote:Yes, me too, and I'm not 60 yet.(06222020 01:07 AM)Joe Horn Wrote: OH NO! We covered all this just 3 years ago, but I don't remember having done so AT ALL. The conclusion is undeniable: I'm now officially OLD... two months before my 65th birthday.Don't worry Joe, +1 even if I'm just a bit younger... I just tried the 29C in emulation and was surprised to see a different answer  was there another change in HP's arithmetic? Here are my results: HP25: 9.99E08 (same as emulated HP35 with V4 ROM) HP67: 1E09 (microcode emulation) HP 29C: 1E09 (microcode emulation) HP 35s: zero HP 30b: zero HP15C LE: zero (I think the LE uses the same algorithms as the original 15C) 

06222020, 03:05 PM
(This post was last modified: 06222020 04:10 PM by AndiGer.)
Post: #16




RE: Which HP calculator had "The New Accuracy" first?
Real HP22 gives the same result as Tony's CCE33: 1.0000000 E09 (for 729^33.5 / 3^201  1)


06222020, 04:07 PM
Post: #17




RE: Which HP calculator had "The New Accuracy" first?
(06222020 01:53 PM)EdS2 Wrote: HP15C LE: zero Quite possibly. A DM15L (using the HP15C ROM) makes 2^3 precisely 8. There are only 10 types of people in this world. Those who understand binary and those who don't. 

06222020, 04:52 PM
Post: #18




RE: Which HP calculator had "The New Accuracy" first?
Hmm, I see that if we subtract the two powers instead of dividing them, we learn a little more:
HP35 (v4 ROM) 7.96E88 HP25C 7.96E88 HP29C 5E86 HP15C (LE) 2E86 HP 30b 2E84 HP 35s 2E84 Also, it occurred to me that if we're seeking families of machines which use the same algorithms and machinery, we should expect the calculator forensics test to produce a related grouping  perhaps a slightly coarser one. (Instead of measuring log and exp, we're measuring trig, so it might not be coarser, just different.) From the results page: 9.004076901 HP35v3 9.004076644 HP45, HP46, HP65 9.004076898 HP55 9.004076649 HP21, HP25, HP25C 9.000417403 HP27 HP19C HP29C HP41C HP41CV HP67 HP91 HP97, HP97S HP10C, HP11C, HP15C (Voyager) HP31E, HP32E, HP33E, HP34C (Spice) 

06222020, 04:59 PM
Post: #19




RE: Which HP calculator had "The New Accuracy" first?
(06222020 09:51 AM)EdS2 Wrote: I'm just a little worried by a test case that involves small integers like this. Another example given by Kahan as an accuracy test is this: Hi, I've tested on my HP10bII+, too pi * e  e * pi > gives 0 [ in Algebric mode with Л x e^1  e^1 x Л = ] 729^33.5 / 3^201 1 > gives 0 [ with 729^33.5 ÷ ( 3^201 )  1 = ] But, LN 729 x 33.5 ÷ ( LN 3 x 201 )  1 = gives 5E12 (and curiously 1,00000000 in DISP . mode before applying  1 = ) 

06222020, 07:11 PM
Post: #20




RE: Which HP calculator had "The New Accuracy" first?  
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