(Crosspost from MoHPC HP Forums):
Today I stumbled about a footnote in Walter's WP 34S Owner's manual, where at Page 319 the result of the Calculator Forensics Test is mentioned. To my big surprise, the DP difference between the test result, and 9, is
for WP 34S: 6.2465E29
for DM42: 6.2466E29
But why the differerence of 1 ULP?? For the other example (1.0000001^(2^27)), there isn't any difference between the two models, BTW.
WP 34S vs. DM42 decimal128 differences?
WP 34S vs. DM42 decimal128 differences?
Last edited by rkf on Fri Mar 23, 2018 8:43 am, edited 1 time in total.
DM42 S/N 00761
Re: WP 34S vs. DM42 decimal128 differences?
If I've understood said test correctly then its results point to different processors and firmware used in different physical calculators. So a slight difference in the results between WP 34S and DM42 wouldn't bother me since both parameters are definitively different.
EDIT: The WP 34S Emulator returns the same as the calculator does: so the WP 34S result is a matter of SW/FW only.
EDIT: The WP 34S Emulator returns the same as the calculator does: so the WP 34S result is a matter of SW/FW only.
DM42 SN: 00041  Follower of Platon.
HP35, HP45, ..., HP50, WP 34S, WP 31S, DM16L
HP35, HP45, ..., HP50, WP 34S, WP 31S, DM16L
Re: WP 34S vs. DM42 decimal128 differences?
comparison of the intermediate results between Free42 and WP34S:
Where the two are different, the result of the WP34S is correct to all digits.
Cheers, Werner
Code: Select all
DEG Free42 WP34S
9
SIN 1.56434465040230869010105319467166801 1.56434465040230869010105319467166901
COS 9.99996272742885024117516205011350201 =
TAN 1.74549998554886607913941409283484702 =
ATAN 9.99996272742885024117516205011350301 =
ACOS 1.56434465040230869010105319466090101 =
ASIN 8.999999999999999999999999999937534 00 8.999999999999999999999999999937535 00
Cheers, Werner
42S #3249S01123
DM42 #00345
DM42 #00345
Re: WP 34S vs. DM42 decimal128 differences?
Kudos to Pauli!
DM42 SN: 00041  Follower of Platon.
HP35, HP45, ..., HP50, WP 34S, WP 31S, DM16L
HP35, HP45, ..., HP50, WP 34S, WP 31S, DM16L

 Posts: 463
 Joined: Wed May 03, 2017 5:46 pm
 Location: Malone, NY USA
Re: WP 34S vs. DM42 decimal128 differences?
By correct, do you mean the last digit itself is correct or that the answer is correct when rounded to that many places?whuyse wrote: ↑Wed Mar 21, 2018 7:55 amcomparison of the intermediate results between Free42 and WP34S:
Where the two are different, the result of the WP34S is correct to all digits.Code: Select all
DEG Free42 WP34S 9 SIN 1.56434465040230869010105319467166801 1.56434465040230869010105319467166901 COS 9.99996272742885024117516205011350201 = TAN 1.74549998554886607913941409283484702 = ATAN 9.99996272742885024117516205011350301 = ACOS 1.56434465040230869010105319466090101 = ASIN 8.999999999999999999999999999937534 00 8.999999999999999999999999999937535 00
Cheers, Werner
Example:
2/3 to 6 places:
.666666 All digits correctly truncated.
.666667 Correctly rounded to 6 places.
Both are "correct" for the way they're calculated.
In SIN and ASIN above, it looks like the 34S rounds while Free42 truncates. If we could see one more digit of the true answer, we'd know.
Tom L
Ducator meus nihil agit sine lagunculae leynidae accedunt
DM42 SN: 00025 (Beta)
SN: 00221 (Shipping)
Ducator meus nihil agit sine lagunculae leynidae accedunt
DM42 SN: 00025 (Beta)
SN: 00221 (Shipping)
Re: WP 34S vs. DM42 decimal128 differences?
I mean 'correctly rounded'.
9 SINDEG ends in ..668923 so the correctly rounded result is ..669
ASINDEG(1.56434465040230869010105319466090101) ends in ..535301, so ..535 is the correct answer, and it's not a matter of rounding vs. truncating.
Free42 is occasionally an ULP wrong because it doesn't have the 39digit intermediate format the WP34S has. Well, that's my guess.
Cheers, Werner
9 SINDEG ends in ..668923 so the correctly rounded result is ..669
ASINDEG(1.56434465040230869010105319466090101) ends in ..535301, so ..535 is the correct answer, and it's not a matter of rounding vs. truncating.
Free42 is occasionally an ULP wrong because it doesn't have the 39digit intermediate format the WP34S has. Well, that's my guess.
Cheers, Werner
42S #3249S01123
DM42 #00345
DM42 #00345