Folks,
Has anyone run the Calculator Forensics formula on the HP15C LE?
Just being curious, mine is still awaiting shipment in some distant warehouse...
Joel Setton
HP15C LE calculator forensics?


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09102011, 11:43 AM
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09102011, 12:21 PM
It has to be the same as the original 15c, it's just an emulator running the 15c ROM image. ▼
09102011, 12:51 PM
Yes, the numerical results are always identical between the 15C and 15CLE. Even the sequence of random numbers generated after reset with the RAN# command is identical. ▼
09102011, 03:01 PM
BTW, even the 12C Platinum can be programmed to replicate the original 15C forensic results. From article #654: 1) asin(acos(atan(tan(cos(sin(9)))))):
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I will run the program in message #19 of this thread. The result should be 534,912,768.0That's a solution to Karl Schneider's interesting challenge, that is, 5/34 + 9/12 + 7/68 = 1No one should try this on his/her new HP15C LE as it will take about 7 hours to run. I hope the batteries last that long :) (Valentin Albillo presented later a faster 15C program, about 850 times as fast).
09102011, 02:20 PM
I would be interested in the results of the calculator torture tests:Torture
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09102011, 05:33 PM
I don't quite agree with the results for the HP15C.
round #1: accuracy of tan(355/226)
Quote: But there's no way to enter 355/226 into this calculator. The best you can do is to calculate that number which is 1.570796460. That's why we have to compare the result of tan(1.570796460).
round #2: cube root of 27After setting complex mode (SF 8) I get the correct answer: 1.5000 + 2.5981i instead of Error 0.
round #3: definite integration3.5: integrate(sqrt(abs(x1)), 0, 2)
The HP15C has an issue with this integral. However
Thanks for pointing out this torture test. ▼
09102011, 06:57 PM
Since we had this discussion on how the new 15C compares to the 35s, here are the results for the latter:
Dieter
Edited: 10 Sept 2011, 7:03 p.m. ▼
09102011, 09:04 PM
Quote: Some are known. How much faith do you have that all are? :)
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09112011, 09:12 AM
Well, after four years of use now I am quite sure that all relevant bugs are known. As opposed to the brand new 15C which the community will still have to scrutinize. ;) Dieter
09112011, 01:50 AM
Quote: How long is a moment? Because I stopped the integration on my HP35s after a minute or so. I've tried both ways: using a program and an equation. Does anybody have an idea what's going wrong here? To me this function doesn't apear to be wild. Ok, there's a singularity of the first derivative at x = 1. But why isn't it a problem when it is used as lower limit?
This is another function most HP calculators seem to have a problem with: f(x) = Sqrt[x (2  x)]. It describes a circle with radius r = 1 and center at (1, 0) or (1, 0). Integrating this function from 0 to 2 is not a problem. But when the interval [1, 1] is used it takes much longer or seems to never end. While I knew that Rombergintegration has a problem with these kind of singularities I wasn't aware that this happens only when they are located inside the interval.
Thomas Edited: 11 Sept 2011, 4:22 a.m. ▼
09112011, 07:44 AM
The 35s took 40  45 seconds for the integral in FIX 4 mode. The function had been entered as an equation. Since this elegant feature is available: use it. ;) Edit: I also tried the function you mentioned over [1; 1] on the 35s. For a first look at the result I set FIX 2 and the result was returned immediately as 1,52 (last digit is off). FIX 3 returns 1,570 (correct within 1 ULP) after 16 seconds. Finally, FIX 4 requires two minutes, but comes back with the correct result 1,5708 as well. :) Dieter
Edited: 11 Sept 2011, 8:52 a.m.
09112011, 03:47 AM
Quote:
Quote: Just never try this in combination: 27 i 0 [ENTER] 3 [XROOT] => INVALID DATA Duh!
09102011, 07:37 PM
Quote: You are right. It would not be fair to compare the calculators results with the exact result of tan(355/226).
correct 16digit answer, tan(1.570796460) = 7507219.878366671 Gerson.
Edited: 10 Sept 2011, 7:48 p.m. ▼
09112011, 04:14 AM
I kind of hope you weren't using the 34S as the 16 digit benchmark for this. In this case, the 34S is correct but please nobody assume it is everywhere, I've done no theoretic error analysis and the number of values actually validated is tiny. That all said, definitely let me know when it isn't correct within +/ 1 in the last digit :)
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09112011, 07:48 AM
Pauli, if 39 digits of internal precision were not able to provide a correct 16 digit result you would have done something seriously wrong. ;) Dieter ▼
09112011, 08:10 AM
And to be honest, I'm not at all sure I haven't done something seriously wrong somewhere. There is a *lot* of numeric code in the 34S and some of it is bound to be slightly incorrect (or worse).
09112011, 12:38 PM
Quote:.
I used WolframAlpha's result truncated at the second zero: 7.5072198783666710922545119574391592156309211475564175... × 10^6 This, of course, would sure match the wp34s's result :) Gerson.
09112011, 08:01 AM
Quote:As already mentioned in a previous message, this tangent evaluation is extremely prone to errors. Since the argument may always be off by plus or minus 5 E10, the tangent may vary by ~28000 (!) or a relative error of 3,7 E3. Yes, the tangent of 1,57079646000000000000000000000.... has the mentioned value, but in real life we are dealing with irrational numbers (i.e. #digits is infinite), so we cannot expect correct results for tan(x_close_to_pi/2) at all. Dieter 