WP 34S vs. DM42 decimal128 differences?

[Dieter]

(03-20-2018 09:15 AM)rkf Wrote:  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: -6.2465E-29
for DM42: -6.2466E-29

But why the differerence of 1 ULP?? For the other example (1.0000001^27), there isn't any difference between the two models, BTW.

Both calculators use 34-digit precision, but this does not mean that they return the same results. The trig functions may be implemented differently, and there is no claim (at least for the 34s) that all 34 digits are correct. The 34s also has different round modes that can be set, which will affect the result as well.

Dieter